EXJ_599 jeep xj service manual

7/29/2019 EXJ_599 jeep xj service manual

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BRAKES

CONTENTS

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ANTILOCK BRAKES . . . . . . . . . . . . . . . . . . . . . 30 BASE BRAKE SYSTEM . . . . . . . . . . . . . . . . . . . . 1

BASE BRAKE SYSTEM

INDEX

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GENERAL INFORMATIONBRAKE SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . 2SERVICE WARNINGS & CAUTIONS . . . . . . . . . 2

DESCRIPTION AND OPERATIONBRAKE HOSES AND LINES . . . . . . . . . . . . . . . . 5

BRAKE PEDAL . . . . . . . . . . . . . . . . . . . . . . . . . . 2COMBINATION VALVE . . . . . . . . . . . . . . . . . . . . 3FRONT DISC BRAKES . . . . . . . . . . . . . . . . . . . . 3MASTER CYLINDER . . . . . . . . . . . . . . . . . . . . . 3

PARKING BRAKE . . . . . . . . . . . . . . . . . . . . . . . . 4POWER BRAKE BOOSTER . . . . . . . . . . . . . . . . 2REAR DRUM BRAKE . . . . . . . . . . . . . . . . . . . . . 3RED BRAKE WARNING LAMP . . . . . . . . . . . . . . 2

STOP LAMP SWITCH . . . . . . . . . . . . . . . . . . . . 2DIAGNOSIS AND TESTING

BASE BRAKE SYSTEM . . . . . . . . . . . . . . . . . . . 5BRAKE DRUM . . . . . . . . . . . . . . . . . . . . . . . . . 10BRAKE FLUID CONTAMINATION . . . . . . . . . . . 11

BRAKE LINE AND HOSES . . . . . . . . . . . . . . . . 10COMBINATION VALVE . . . . . . . . . . . . . . . . . . . . 9DISC BRAKE ROTOR . . . . . . . . . . . . . . . . . . . . 9MASTER CYLINDER/POWER BOOSTER . . . . . . 8

RED BRAKE WARNING LAMP . . . . . . . . . . . . . . 8STOP LAMP SWITCH . . . . . . . . . . . . . . . . . . . . 8

SERVICE PROCEDURES

BRAKE BLEEDING . . . . . . . . . . . . . . . . . . . . . . 11BRAKE DRUM MACHINING . . . . . . . . . . . . . . . 12BRAKE FLUID LEVEL . . . . . . . . . . . . . . . . . . . . 11BRAKE LINE . . . . . . . . . . . . . . . . . . . . . . . . . . 12DISC ROTOR MACHINING . . . . . . . . . . . . . . . . 12

MASTER CYLINDER BLEEDING . . . . . . . . . . . 11

REMOVAL AND INSTALLATIONBRAKE PEDAL . . . . . . . . . . . . . . . . . . . . . . . . . 14BRAKE SUPPORT PLATE . . . . . . . . . . . . . . . . 20COMBINATION VALVE . . . . . . . . . . . . . . . . . . . 14DISC BRAKE CALIPER . . . . . . . . . . . . . . . . . . 16

DISC BRAKE ROTOR . . . . . . . . . . . . . . . . . . . 18DISC BRAKE SHOES . . . . . . . . . . . . . . . . . . . . 17DRUM BRAKE SHOES . . . . . . . . . . . . . . . . . . . 19MASTER CYLINDER . . . . . . . . . . . . . . . . . . . . 15

PARKING BRAKE LEVER . . . . . . . . . . . . . . . . . 21POWER BRAKE BOOSTER . . . . . . . . . . . . . . . 15REAR PARKING BRAKE CABLES . . . . . . . . . . 21STOP LAMP SWITCH . . . . . . . . . . . . . . . . . . . . 13

WHEEL CYLINDER . . . . . . . . . . . . . . . . . . . . . 20DISASSEMBLY AND ASSEMBLY

DISC BRAKE CALIPER . . . . . . . . . . . . . . . . . . 23MASTER CYLINDER RESERVOIR . . . . . . . . . . 22WHEEL CYLINDER . . . . . . . . . . . . . . . . . . . . . 24

CLEANING AND INSPECTIONCALIPER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25REAR DRUM BRAKE . . . . . . . . . . . . . . . . . . . . 25WHEEL CYLINDER . . . . . . . . . . . . . . . . . . . . . 26

ADJUSTMENTSPARKING BRAKE CABLE TENSIONER . . . . . . 28REAR DRUM BRAKE . . . . . . . . . . . . . . . . . . . . 26

STOP LAMP SWITCH . . . . . . . . . . . . . . . . . . . . 26SPECIFICATIONSBRAKE COMPONENTS . . . . . . . . . . . . . . . . . . 29BRAKE FLUID . . . . . . . . . . . . . . . . . . . . . . . . . 28TORQUE CHART . . . . . . . . . . . . . . . . . . . . . . . 29

SPECIAL TOOLSBASE BRAKES . . . . . . . . . . . . . . . . . . . . . . . . 29

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GENERAL INFORMATION

BRAKE SYSTEM

P o w e r a s s i s t f r o n t d i s c a n d r e a r d r u m b r a k e s a r e

st a n d a r d e q u ip m e n t . D isc br a k e co m p o n e n t s co n sist

o f s in g le p ist o n ca l ip e r s a n d ve n t i la t e d r o t o r s. Re a r

d r um b ra k es a r e d ua l s h oe u n it s w i t h ca s t b ra k edrums.

Th e p a r k in g br a k e m e ch a n ism is le ver a n d ca ble

op er a t e d . Th e ca b l es a r e a t t a ch ed t o l ev er s on t h e

r ea r d r um b ra k e s econ d a r y s h oes . Th e p a rk in g

br a k e s a r e o p e r a t e d by a h a n d le ve r .

A d u a l d ia p h r a g m va cu u m p o w e r br a k e bo o st e r is

used for a ll a pplicat ions. All models h ave a tw o-piece

master cylinder with plastic reservoir .

All models are equipped with a combination valve.

Th e va lve con t a in s a p r essu r e d if fe r en t ia l va lve a n d

sw it ch a n d a f ixe d r a t e r e a r p r op or t ion in g va lve .

F a ct o r y br a k e l in in g o n a l l m o d e ls co n sist s o f a n

o r g a n ic ba se m a t e r ia l co m bin e d w it h m e t a l l ic p a r t i-cles. The lining does not contain asbestos.

SERVICE WARNINGS & CAUTIONS

WARNING: FACTORY INSTALLED BRAKE LININGSDO NOT CONTAIN ASBESTOS FIBERS. DUST AND

DIRT ACCUMULATING ON BRAKE PARTS DURINGNORMAL USE MAY CONTAIN ASBESTOS FIBERSFROM AFTER MARKET BRAKE LININGS. BREATH-ING EXCESSIVE CONCENTRATIONS OF ASBESTOS

FIBERS CAN CAUSE SERIOUS BODILY HARM.EXERCISE CARE WHEN SERVICING BRAKE

PARTS. DO NOT CLEAN BRAKE PARTS WITH COM-PRESSED AIR OR BY DRY BRUSHING. USE A VAC-

UUM CLEANER SPECIFICALLY DESIGNED FORTHE REMOVAL OF ASBESTOS FIBERS FROMBRAKE COMPONENTS. IF A SUITABLE VACUUMCLEANER IS NOT AVAILABLE, CLEANING SHOULD

BE DONE WITH A WATER DAMPENED CLOTH. DONOT SAND, OR GRIND BRAKE LINING UNLESSEQUIPMENT USED IS DESIGNED TO CONTAIN THEDUST RESIDUE. DISPOSE OF ALL RESIDUE CON-TAINING ASBESTOS FIBERS IN SEALED BAGS OR

CONTAINERS TO MINIMIZE EXPOSURE TO YOUR-SELF AND OTHERS. FOLLOW PRACTICES PRE-SCRIBED BY THE OCCUPATIONAL SAFETY ANDHEALTH ADMINISTRATION AND THE ENVIRONMEN-

TAL PROTECTION AGENCY FOR THE HANDLING,PROCESSING, AND DISPOSITION OF DUST ORDEBRIS THAT MAY CONTAIN ASBESTOS FIBERS.

CAUTION: Never use gasoline, kerosene, alcohol,

motor oil, transmission fluid, or any fluid containingmineral oil to clean the system components. Thesefluids damage rubber cups and seals. Use onlyfresh brake fluid or Mopar brake cleaner to clean or

flush brake system components. These are the onlycleaning materials recommended. If system contam-ination is suspected, check the fluid for dirt, discol-oration, or separation into distinct layers. Drain andflush the system with new brake fluid if contamina-

tion is suspected.

CAUTION: Use Mopar brake fluid, or an equivalentquality fluid meeting SAE/DOT standards J1703 andDOT 3. Brake fluid must be clean and free of con-

taminants. Use fresh fluid from sealed containersonly to ensure proper antilock component opera-tion.

CAUTION: Use Mopar multi-mileage or high temper-

ature grease to lubricate caliper slide surfaces,drum brake pivot pins, and shoe contact points onthe backing plates. Use multi-mileage grease or GE

661 or Dow 111 silicone grease on caliper bushingsand slide pins to ensure proper operation.

DESCRIPTION AND OPERATION

BRAKE PEDAL

A su spe n d ed -t y p e br a k e p ed a l is u sed , t h e p ed a l

p iv ot s on a s h a ft m ou n ted i n t h e p ed a l s upp or t

b r a ck et . Th e b r a ck et i s a t t a ch ed t o t h e d a s h p a n el

and steering support bracket. The unit is serviced as

an assembly, except for the pedal pad.

STOP LAMP SWITCH

The plunger t ype stop lamp sw itch is mounted on a

b r a ck et a t t a ch ed t o t h e b r a k e p e da l s u pp or t . Th e

sw it ch ca n be a d ju st e d w h e n n e cessa r y.

RED BRAKE WARNING LAMP

A r e d w a r n in g la m p is u se d f o r t h e se r vice br a k e

portion of the hydraulic system. The lamp is located

in the instrument cluster.

Th e r e d w a r n in g l igh t a le r t s t h e d r ive r i f a p r es-

s u r e d i f fer en t i a l e xi st s b et w e en t h e f r on t a n d r ea r

h y d r a u li c s y s t e m s. Th e l ig h t a l s o a l er t s t h e d r iv er

w h e n t h e p a r k in g br a k e s a r e a p p lie d .

POWER BRAKE BOOSTER

The booster assembly consists of a housing divided

in t o se p a r a t e ch a m be r s by t w o in t e r n a l d ia p h r a g m s.

T h e o u t e r e d g e o f e a ch d ia p h r a g m is a t t a ch e d t o t h e

boost e r h ou sin g. Th e d ia p h r a g m s a r e con n e ct e d t o

the booster primary push rod.

Tw o p u sh r od s a r e u sed in t h e boost e r. Th e p r i-

m a r y p us h r od con n ect s t h e b oos t er t o t h e b r a k e

pedal. The secondary push rod connects the booster

to the master cylinder to stroke the cylinder pistons.

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The a tmospheric inlet valve is opened an d closed

by t h e p r im a r y p u sh r o d . B o o st e r va cu u m su p p ly is

t h r o ug h a h ose a t t a ch e d t o a n in t a k e m a n if old f i t t in g

a t on e e n d a n d t o t h e b oos t er ch eck v a lv e a t t h e

other. The vacuum check valve in the booster housing

is a one-way device that prevents vacuum leak back.

P ow e r a ssist is g en e r a t e d by u t i l iz in g t h e p r essu r ed iff er e n t ia l bet w e e n n or m a l a t m osp h er ic p r essu r e

and a vacuum. The vacuum needed for booster oper-

a t io n is t a k e n d ir e ct ly f r o m t h e e n g in e in t a k e m a n i-

f ol d . Th e e nt r y p oi n t f or a t m o sp her i c p re ss u r e i s

t h r ou gh a f il t er a n d i nl et v a lv e a t t h e r ea r of t h e

housing (Fig. 1).

Th e ch a m b er a r e a s f or w a r d of t h e b oos t er d ia -

ph r a gm s a r e exp os ed t o v a cu um f rom t h e i nt a k e

m a n if o ld . T h e ch a m be r a r e a s t o t h e r e a r o f t h e d ia -

p h r a g m s, a r e e xp osed t o n or m a l a t m osp h er ic p r e s-

sure of 101.3 kilopa scals (14.7 pounds/squa re in.).

B r a k e p ed a l a p p lica t io n ca u se s t h e p r im a r y p u sh

rod to open the atmospheric inlet valve. This exposest h e a r e a beh in d t h e d ia p h r a g m s t o a t m osp h er ic p re s-

sure. The r esult ing pressure differentia l provides the

extra apply pressure for power assist .

MASTER CYLINDER

Th e m a st e r cy lin d er h a s a r e m ova ble n y lon r e ser -

v oi r. Th e cy li n der b od y i s m a d e of a l u m in u m a n d

con t a in s a p r im a r y a n d secon d a r y p ist o n a ssem bly.

Th e cy lin d e r bod y in clu d in g t h e p ist o n a sse m blies

are not serviceable. If diagnosis indicates an internal

p r oblem w it h t h e cy lin d er bod y, i t m u st be r e p la ce d

a s a n a sse m bly . T h e r e se r vo ir a n d g r o m m e t s a r e t h e

only replaceable parts on the master cylinder.

COMBIN ATION VALVE

The combina tion va lve conta ins a pressure differ-

e n t ia l va lve a n d sw it ch a n d a r e a r br a k e p r o p o r t io n -

i n g v a l v e. Th e v a l v e i s n ot r ep a ir a b l e. I t m u s t b e

replaced if diagnosis indicates this is necessary.

The pressure differential switch is connected to t he

brake warning light . The switch is actuated by move-

m e n t of t h e sw it ch va lve. Th e sw it ch m on it or s f luid

p r essu r e in t h e se pa r a t e f r on t /r e a r br a k e h y d r a u lic

circuits.

A d ecr ea s e or l os s of f lu id p res su r e i n ei t her

h y d r a u lic cir cu it w ill ca u se t h e sw it ch va lve t o sh u t -

t le t o t h e low p r essu r e sid e. Movem e n t of t h e va lve

pushes the switch plunger upwa rd. This a ction closes

the switch internal contacts completing the electrical

circuit to the red warning light . The switch valve will

r em a i n i n a n a ct u a t ed pos it i on u nt i l r epa i r s a r e

m a d e .

Th e r ea r p rop or t i on i ng v a l ve i s u s ed t o b a l a n ce

f r on t -r ea r b r a k e a c t ion . Th e v a l ve a l l ow s n or m a l

f luid f low d u r in g m od e r a t e e ff or t br a k e st op s. Th e

va lve on ly con t r o ls (m e t er s) f lu id f low d u r in g h ig h

effort brake stops.

FRONT DISC BRAKES

The calipers are a single piston type. The calipers

ar e free to slide lat erally, t his a llows continuous com-

pensation for lining wear.Wh en t h e b r a k es a r e a p pl ie d f lu id p re ss u r e i s

exerted against the caliper piston. The fluid pressure

is e x e r t e d e q u a lly a n d in a l l d ir e ct io n s. T h is m e a n s

p res su r e exer t ed a g a i ns t t h e ca l iper pi st on a n d

within the caliper bore will be equal (Fig. 2).

Fluid pressure applied to the piston is transmitted

d ir ect ly t o t h e in boa r d br a k e sh oe . Th is f or ce s t h e

s h oe l in in g a g a i ns t t h e i nn er s ur fa c e o f t h e d is c

br a k e r o t or. At t h e sa m e t im e , f lu id p r essu r e w it h in

t h e p ist o n bo r e f or ce s t h e ca l ip er t o sl id e in w a r d on

t h e m o u n t in g bo lt s . T h is a ct io n br in g s t h e o u t bo a r d

br a k e sh o e l in in g in t o con t a ct w it h t h e o u t e r su r f a ce

of the disc brake rotor.I n su m m a r y , f lu id p r e ssu r e a ct in g sim u lt a n e o u sly

on both piston and caliper, produces a strong clamp-

ing action. When sufficient force is applied, fr ict ion

w il l s t o p t h e r o t o r s f r o m t u r n in g a n d br in g t h e ve h i-

cle t o a st o p.

Ap p lica t io n a n d r e le a se o f t h e br a k e p e d a l g e n e r -

a t e s o n ly a ve r y sl ig h t m o ve m e n t o f t h e ca l ip e r a n d

piston. U pon r elease of the pedal, t he caliper a nd pis-

ton return to a rest posit ion. The brake shoes do not

r et r a c t a n a p pr eci a b le d is t a n ce f r om t h e r ot or. I n

fact , cleara nce is usua lly a t , or close to zero. The rea -

s on s f or t h i s a r e t o k e ep r oa d d eb r is f r om g et t i n g

be t w e e n t h e r o t o r a n d l in in g a n d in w ip in g t h e r o t o rsurface clear each revolution.

The caliper piston seal controls the amount of pis-

ton extension needed t o compensate for normal lining

w e a r .

During brake application, the seal is deflected out-

ward by fluid pressure and piston movement (Fig. 3).

Wh e n t h e br a k e s (a n d f luid p r essu r e) a r e r e le a sed ,

t h e se a l r e la x e s a n d r e t r a ct s t h e p ist o n .

Th e a m o u n t of p ist on r e t r a ct ion is d e t er m in ed by

b ra k e l in in g w e a r. G e n er a l ly t h e a m ou n t i s ju st

e n o u g h t o m a in t a in co n t a ct be t w e e n t h e p ist o n a n d

inboard brake shoe.

REAR D RUM BRAKE

Th e b r a k e s y s t em s u s e a l ea d i n g s h oe (p ri m a r y )

a n d t r a i l in g s h oe (s econ d a r y ) (F i g. 4). Wh en t h e

br a k e p e d a l is d e p r e sse d h y d r a u lic p r e ssu r e p u sh e s

t h e r e a r br a k e w h e e l cy l in d e r p ist o n s o u t w a r d . T h e

w h e e l cy lin d er p u sh r od s t h e n p u sh t h e br a k e sh o es

ou t w a r d a g a i ns t t h e b ra k e d r um . Wh en t h e b ra k e

p ed a l i s r el ea s ed r et u rn s pr in gs a t t a c hed t o t h e

b r a k e s h o es p ul l t h e s h oe s b a ck t o t h er e or i gi n a l

position.

XJ BRAKES 5 - 3

DESCRIPTION AND OPERATION (Continued)


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PARKING BRAKE

Pa r k in g br a k e a d ju st m e n t is co n t r o lle d by a ca ble

t e ns i on er m ech a n i s m. Th e ca b l e t e n si on er, on ce

a d ju st ed a t t h e f a ct or y, s h ou ld n ot n eed f ur t h er

adjustment under normal circumstances. Adjustment

m a y b e r e q u ir ed i f a n ew t e n si on er, or ca b l es a r e

insta lled, or disconnected.

PARKING BRAKE OPERATION

A h a n d o p e r a t e d le ve r in t h e p a sse n g e r co m p a r t -

ment is the main application device. The front cable

i s con n ect e d b et w e en t h e h a n d l ev er a n d t h e t e n -

sioner. The tensioner rod is at tached to the equalizer

which is the connecting point for the rea r cables (Fig.

5).

Th e r ea r ca b l es a r e con n ect e d t o t h e a c t u a t i ng

lever on e a ch secon d a r y br a k e sh oe . Th e lever s a r e

a t t a ch e d t o t h e br a k e sh oe s by a p in e it h e r p r essed

into, or welded to the lever. A clip is used to secure

the pin in the brake shoe. The pin allows each lever

to pivot independently of the brake shoe.

To a p pl y t h e p a r ki n g b r a k es , t h e h a n d l ev er i s

p u lle d u p w a r d . T h is p u lls t h e r e a r br a k e sh o e a ct u -

a t in g leve rs f or w a r d , by m e a n s t e n sion e r a n d ca ble s.

As t h e a ct u a t in g le ver is p u lle d f or w a r d , t h e p a r k in gbrake strut (which is connected to both shoes), exerts

a l in e a r f or ce a g a in st t h e p r im a r y br a k e sh o e. Th is

action presses the primary shoe into contact with the

d ru m . O nce t h e p ri ma r y s h oe con t a ct s t h e d r um ,

force is exerted th rough the st rut . This force is t ran s-

f er r e d t h r o u gh t h e st r u t t o t h e se con d a r y br a k e sh o e

ca u sin g i t t o p ivo t in t o t h e d r u m a s w e ll .

A g e a r t y p e r a t ch e t in g m e ch a n ism is u se d t o h o ld

t h e l ev er i n a n a p pl ied pos it i on . P a r ki ng b ra k e

r el ea s e i s a c com p li sh ed b y t h e h a n d l ev er r el ea s e

button.

Fig. 1 Power Brake BoosterTypical

VACUUMCHECK VALVE FRONT DIA-PHRAGM REAR DIA-PHRAGM HOUSING SEAL AIR FILTERPRIMARY PUSHROD (TO BRAKEPEDAL)ATMOSPHERICINLET VALVEASSEMBLYBOOSTERMOUNTINGSTUDS (4)SECONDARY PUSHR OD (TO M AS TERCYLINDER)MASTER CYLINDERMOUNTING STUD (2) SPRING

5 - 4 BRAKES XJ



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A pa r k in g br a k e sw it ch is m ou n t e d o n t h e p a r k in g

b ra k e l ev er a n d i s a c t ua t e d b y m ov em en t of t h e

lever . Th e sw it ch , w h ich is in cir cu it w it h t h e r e d

w a r n i n g l i gh t i n t h e d a s h , w i l l i ll um i n a t e t h e w a r n -

in g l ig h t w h e n e ve r t h e p a r k in g br a k e s a r e a p p lie d .

BRAKE HOSES AND LINES

F lex ible r u bbe r h o se is u sed a t bot h f r on t br a k e sa n d a t t h e r ea r a x l e j un ct i on b lock . D ou b le w a l l ed

steel tubing is used to connect the master cylinder to

t h e m a jor h y d r a u lic br a k in g com p on e n t s a n d t h e n t o

the flexible rubber h oses.

DIAGNOSIS AND TESTING

BASE BRAKE SYSTEM

Base brake components consist of the brake shoes,

calipers, wheel cylinders, brake drums, rotors, brake

lin e s, m a st e r cy lin d er, boost e r, a n d p a r k in g br a k e

components.

B r a k e d ia g n o sis in vo lve s d e t e r m in in g i f t h e p r o b-

lem is r e la t e d t o a m e ch a n ica l , h y d r a u lic, o r va cu u m

operated component.

The first diagnosis step is the preliminary check.

PRELIMINARY BRAKE CHECK

(1) C h e ck co n d it io n o f t ir e s a n d w h e e ls. D a m a g e d

w h e el s a n d w o rn , d a m a g e d, or u n d er i nf la t e d t i r es

ca n ca u se p u ll , sh u d d e r, vibr a t io n , a n d a con d it ion

sim ila r t o g r a b.

(2) I f com p la in t w a s ba se d o n n o ise w h e n br a k in g,

check suspension components. J ounce front an d rear

o f ve h icle a n d l ist e n f o r n o ise t h a t m ig h t be ca u se d

by loose , w or n or d a m a g ed su spe n sion or st e er in g

components.

(3) I n sp e ct br a k e f lu id level a n d con d it ion . N ot e

t h a t t h e f r on t d i sc b r a k e r e s er v oi r f lu i d l ev el w i l l

d e cr e a se in p r op or t ion t o n or m a l l inin g w e a r . Alsonote that brake fluid tends to darken over time.This is normal and should not be mistaken forcontamination.

(a) If f luid level is abnormally low, look for evi-

d e n ce of lea k s a t ca l ip er s, w h e e l cy lin d er s, br a k e

lines, and master cylinder.

(b ) I f f lu id a p pea r s con t a m i n a t e d, d r a i n ou t a

s a m p le. S y s t em w i ll h a v e t o b e f lu s h ed i f f l u id i s

s epa r a t e d i nt o l a y er s , or con t a i ns a s ub st a n ce

o t h e r t h a n br a k e f lu id . T h e sy st e m se a ls a n d cu p s

w i l l a l so h a v e t o b e r e pl a ced a f t e r f lu s h in g . U s e

cle a n br a k e f lu id t o f lu sh t h e sy st e m .

(4) C h eck p a r ki n g b r a k e op er a t i on . Ve ri fy f r eem o ve m e n t a n d f u ll r e le a se o f ca ble s a n d p e d a l . Also

n ot e i f v eh icl e w a s b ei ng op er a t ed w i t h pa r k in g

brake partially applied.

(5) Check brake pedal operation. Verify that pedal

d oe s n o t b in d a n d h a s a d e q ua t e f r ee p la y. I f p ed a l

la cks f r ee p la y , ch e ck p ed a l a n d p ow e r boost e r f or

bein g loose or f or bin d con d it ion . D o n ot r oa d t e st

until condition is corrected.

(6) I f com p on e n t s ch eck ed a p p ea r O K , r oa d t e st

the vehicle.

ROAD TESTING

(1) I f com p la in t in volved low br a k e p ed a l , p u m pp e d a l a n d n o t e i f i t co m e s ba ck u p t o n o r m a l h e ig h t .

(2) Check brake pedal response with transmission

in N e u t r a l a n d e n g in e r u n n in g . Pe d a l sh o u ld r e m a in

firm under constant foot pressure.

(3) D u r in g r o a d t e st , m a k e n o r m a l a n d f ir m br a k e

st o p s in 25- 40 m p h r a n g e . N o t e f a u lt y br a k e o p e r a -

tion such as low pedal, hard pedal, fade, pedal pulsa-

tion, pull, grab, drag, noise, etc.

Fig. 2 Brake Caliper Operation

CALIPER PISTONPISTONBORESEALINBOARDSHOEOUTBOARDSHOE

Fig. 3 Lining Wear Compensation By Piston Seal

PISTON CYLINDER BOREPISTON SEALB RA KE PR ES -SURE OFF CALIPERHOUSING DUST BOOT PISTONSEALBRAKEPRESSUREON

XJ BRAKES 5 - 5



6/38

PEDAL FALLS AWAY

A b ra k e ped a l t h a t f a ll s a w a y u n der s t ea d y f oot

pressure is generally the result of a system leak. The

le a k p o in t co u ld be a t a br a k e l in e , f i t t in g , h o se , o r

caliper/wheel cylinder. Interna l leakage in the ma stercy li n de r ca u s ed b y w o rn or d a m a g e d p is t on cu ps ,

m a y a lso be t h e p r o ble m ca u se .

I f l ea k a g e i s s ev er e, f lu id w i ll b e ev id en t a t or

a r ou n d t h e l ea k i n g com p on en t . H ow e ve r, i n t er n a l

lea k a g e in t h e m a st e r cyl in de r m a y n ot be p h y sica l ly

evident.

LOW PEDAL

If a low pedal is experienced, pump the pedal sev-

e r a l t im e s. I f t h e p e d a l co m e s ba ck u p w o r n l in in g s,

r o t o r s, d r u m s, o r r e a r br a k e s o u t o f a d ju st m e n t a r e

the most likely causes.

SPONGY PEDAL

A sp o n g y p e d a l is m o st o f t e n ca u se d by a ir in t h e

sy st e m . H o w e ve r , t h in br a k e d r u m s o r su bst a n d a r d

br a k e l in es a n d h ose s ca n a lso ca u se a sp on g y p e d a l .

The proper course of action is to bleed the system, or

r e pla ce t h in d r u m s a n d su spe ct q u a li t y br a k e l in es

a n d h ose s.

HARD PEDAL OR HIGH PEDAL EFFORT

A h a r d p e d a l o r h i g h p e d a l e f f o r t m a y b e d u e t o

l in in g t h a t is w a t e r so a k e d , co n t a m in a t e d , g la z e d , o r

badly worn. The power booster or check valve could

also be faulty.

PEDAL PULSATION

Pe d a l p u lsa t io n is ca u se d by co m p o n e n t s t h a t a r e

loose, or beyond tolerance limits.

Th e pr im a r y ca u s e of pu ls a t ion a r e d is c b ra k e

rotors w ith excessive latera l runout or t hickness var i-

a t io n , or ou t of r o u n d br a k e d r u m s. O t h e r ca u se s a r e

lo o se w h e e l be a r in g s o r ca l ip e r s a n d w o r n , d a m a g e d

tires.

NOTE: Some pedal pulsation may be felt duringABS activation.

BRAKE DRAG

B r a k e d r a g o c c u r s w h e n t h e l i n i n g i s i n c o n s t a n t

contact with the rotor or drum. Drag can occur at one

wheel, all wheels, fronts only, or rears only.

Fig. 4 Brake Components

RIGHT REAR BRAKEASSEMBLYADJUSTER LEVERADJUSTERCABLEHOLDDOWN SPRINGAND RETAINERS ADJUSTERLEVERSPRING TRAILING SHOE CYLINDER-TO-SUPPORT SEALHOLDDOWNPINSACCESSPLUGSSUPPORT PLATECABLE HOLE PLUGPARK BRAKE STRUTAND SPRINGADJUSTER SCREWASSEMBLYHOLDDOWNSP RI NG AN DRETAINERSLEADING SHOECABLEGUIDESHOE RETURNSPRINGS SHOE GUIDEPLATE PIN SHOESPRINGPARK BRAKELEVER

Fig. 5 Parking Brake Components

REAR CABLES EQUALIZER FRONT CABLETENSIONER ROD

5 - 6 BRAKES XJ

DIAGNOSIS AND TESTING (Continued)


7/38

Dra g is a product of incomplete bra ke shoe release.

D r a g ca n be m in o r o r se ve r e e n o u g h t o o ve r h e a t t h e

linin g s, r ot o r s a n d d r u m s.

Min o r d r a g w il l u su a lly ca u se sl ig h t su r f a ce ch a r -

r in g o f t h e l in in g . I t ca n a lso g e n e r a t e h a r d sp o t s in

r ot o r s a n d d r u m s f r om t h e over h e a t -cool d ow n p r o-

ce ss . I n m os t ca s e s, t h e r ot or s , d r u ms , w h e el s a n dt ir e s a r e q u it e w a r m t o t h e t o u ch a f t e r t h e ve h icle is

stopped.

S e ve re d r a g ca n ch a r t h e b r a k e l in i ng a l l t h e w a y

t h r ou gh . I t ca n a l so d is t or t a n d s cor e r ot or s a n d

drums to the point of replacement. The wheels, t ires

a n d b ra k e com pon en t s w i ll b e ex tr em el y h ot . I n

s ev er e ca s e s, t h e l in i ng m a y g en er a t e s m ok e a s i t

chars from overheating.

C o m m o n ca u se s o f br a k e d r a g a r e :

S e iz ed or i m pr op er l y a d ju s t ed p a r ki n g b r a k e

cables.

Loose/worn wh eel bea ring.

Seized caliper or wheel cylinder piston. Caliper binding on corroded bushings or rusted

slide surfa ces.

Loose caliper mounting.

D r u m b r a k e s h oe s b in d in g on w o rn /d a m a g e d

support plates.

Misassembled components.

I f b r a k e d r a g occu r s a t a l l w h e el s, t h e p rob le m

m a y be r e la t e d t o a block ed m a st e r cy l in d e r r e t u r n

port, or faulty power booster (binds-does not release).

BRAKE FADE

B r a k e f a d e i s u su a ll y a pr od uct of ov er h ea t i n g

ca u sed by br a k e d r a g . H o w e ve r, br a k e o ver h e a t in ga n d r e s u l t i n g f a d e c a n a l s o b e c a u s e d b y r i d i n g t h e

brake pedal, m aking repeated high deceleration stops

i n a s h or t t i m e s pa n , or con s t a n t b r a k in g on s t ee p

m ou n t a in r oa d s. Re f er t o t h e B r a k e D r a g in f or m a t ion

in this section for causes.

BRAKE PULL

Front brake pull condition could result from:

Contaminated lining in one caliper

Seized caliper piston

Binding caliper

Loose caliper

Rust y a da pter/caliper slide surfa ces

Improper brake shoes

D a m a g e d r o t o r

A w or n , d a m a g e d w h e el b ea r i n g or s u sp en s ion

com pon en t a r e f ur t h er ca u s es of p ul l. A d a m a g ed

f r on t t i r e (b r ui se d, p ly s ep a r a t i on ) ca n a l s o ca u s e

pull.

A common an d frequently misdia gnosed pull condi-

t ion is w h e r e d ir ect ion of p u ll ch a n g e s a f t e r a f ew

st o ps. Th e ca u se is a com bin a t ion of br a k e d r a g f ol-

lo w e d by f a d e a t o n e o f t h e br a k e u n it s .

As t h e d r a g g in g br a k e ove rh e a t s , e ff icien cy is so

r e du ce d t h a t f a d e occu r s. S in ce t h e op posit e br a k e

unit is st ill functioning normally, its braking effect is

m a g n if ie d . Th is ca u se s p u ll t o sw it ch d ir ect ion in

favor of the normally functioning brake unit .

An a d d it ion a l p oin t w h e n d ia g n o sin g a cha n g e in

pull condition concerns brake cool down. Remembert h a t p u ll w il l r e t u r n t o t h e o r ig in a l d ir e ct io n , i f t h e

d r a g g in g br a k e u n it is a l lo w e d t o co o l d o w n (a n d is

not seriously damaged).

REAR BRAKE GRAB OR PULL

Re a r g r a b o r p u ll is u su a lly ca u se d by im p r o p e r ly

a d ju s t ed or s ei zed p a r ki n g b r a k e ca b l es , con t a m i -

n a t ed l in in g , b en t or b in d in g s h oes a n d s uppor t

plates, or improperly assembled components. This is

pa r t icu la r ly t r ue w h en on ly on e r ea r w h eel i s

i nv ol ved . H ow e ver, w h en b ot h r ea r w h eel s a r e

affected, the master cylinder, proportioning valve, or

RWAL valve could be a t fault .

BRAKES DO NOT HOLD AFTER DRIVING THROUGH DEEP

WATER PUDDLES

This condition is generally caused by water soaked

l i n i n g . I f t h e l i n i n g i s o n l y w e t , i t c a n b e d r i e d b y

d r iv in g w i t h t h e b r a k es v er y l ig h t ly a p pl ie d f or a

mile or t wo. However, if th e lining is both soaked a nd

dirt conta minat ed, cleaning an d/or replacement will

be necessary.

BRAKE SQUEAK/SQUEAL

B r a k e sq u e a k o r sq u e a l m a y be d u e t o l in in g s t h a t

a r e w e t o r co n t a m in a t e d w it h br a k e f lu id , g r e a se , o roi l. G l a z e d l i n in g s a n d r ot or s w i t h h a r d s pot s ca n

a lso co n t r ibu t e t o sq u e a k . D ir t a n d f o r e ig n m a t e r ia l

e m be dd e d in t h e br a k e l in in g w il l a lso ca u se sq u e a k /

squeal.

A very loud squeak or squeal is frequently a sign of

s ev er el y w o rn b r a k e l in i ng . I f t h e l in i ng h a s w o rn

t h r o u g h t o t h e br a k e sh o e s in sp o t s, m e t a l- t o - m e t a l

conta ct occurs. If the condition is allowed t o continue,

rotors and drums can become so scored that replace-

ment is necessary.

BRAKE CHATTER

B r a k e c h a t t e r i s u s u a l l y c a u s e d b y l o o s e o r w o r ncomponents, or gla zed/burnt lining. Rotors w ith ha rd

spots can also contribute to chat ter. Additiona l causes

of chatter are out-of-tolerance rotors, brake lining not

secur e ly a t t a ch ed t o t h e sh oe s, loose w h e el bea r in g s

a n d co n t a m in a t e d br a k e l in in g .

THUMP/CLUNK NOISE

Thumping or clunk noises during braking are fre-

quently not ca u se d by br a k e com p on e n t s. I n m a n yca se s, su ch n oises a r e ca u sed by loose o r d a m a g ed

steering, suspension, or engine components. However,

XJ BRAKES 5 - 7



8/38

ca lip e r s t h a t bin d o n t h e sl id e su r f a ce s ca n g e n e r a t e

a t h um p or clu nk n oi se. I n a d dit ion , w or n ou t ,

im pr op er ly a d ju st ed , or im pr op er ly a sse m ble d r e a r

brake shoes can also produce a thump noise.

BRAKE LININ G CONTAM INATION

B r a k e l in in g co n t a m in a t io n is m o st ly a p r o d u ct o fleaking calipers or wheel cylinders, worn seals, driv-

i n g t h r ou g h d eep w a t e r p u d dl es , o r l in i ng t h a t h a s

becom e cove re d w it h g r ea se a n d g r i t d u r in g r e p a ir.

Contaminated lining should be replaced to avoid fur-

ther brake problems.

WHEEL AND TIRE PROBLEMS

S o m e con d it ion s a t t r ibut e d t o br a k e com p on e n t s

m a y a ct u a lly be ca u se d by a w h e e l o r t ir e p r o ble m .

A da m a g ed w h e e l ca n ca u se sh u d d e r, vibr a t io n a n d

p u ll . A w or n or d a m a g ed t ir e ca n a lso ca u se p u ll.

S e ve r e ly w o r n t ir e s w it h ve r y l i t t le t r e a d le f t ca n

p r od u ce a g r a b-like con d it ion a s t h e t ir e lo ses a n drecovers traction. Flat-spotted t ires can cause vibra-

t ion a n d g en e r a t e sh u d d e r d u r in g br a k e o pe r a t ion . A

t i r e w i t h i n t er n a l d a m a g e s u ch a s a s ev er e b r u is e,

cu t , o r p ly se p a r a t io n ca n ca u se p u ll a n d vibr a t io n .

STOP LAMP SWITCH

S t o p la m p sw it ch o p e r a t io n ca n be t e st e d w it h a n

ohmmeter. The ohmmeter is used to check continuity

be t w e e n t h e p in t e r m in a ls a t d i f f e r e n t p lu n g e r p o si-

tions (Fig. 6).

NOTE: The switch wire harness must be discon-

nected before testing switch continuity.

SWITCH CIRCUIT IDENTIFICATION

Terminals 1 a nd 2 a re for bra ke sensor circuit .

Te r m in a ls 5 a n d 6 a r e f o r t h e st o p la m p cir cu it .

Terminals 3 a nd 4 a re for t he speed control cir-

cuit.

SWITCH CONTINUITY TEST

(1) C h e ck co n t in u it y be t w e e n t e r m in a l p in s 5 a n d

6 as follows:

(a) Pull plunger all the way out to fully extended

position.(b ) At t a ch t es t l ea d s t o p in s 5 a n d 6 a n d n ot e

ohmmeter reading.

(c) I f con t i n ui t y e xi st s , p roce ed t o n ex t t e st .

Replace switch if meter indicates lack of continuity

(shorted or open).

(2) C h e ck co n t in u it y be t w e e n t e r m in a l p in s 1 a n d

2 a n d p i n s 3 a n d 4 a s f ol low s :

(a ) P u sh sw it ch plun ger inw a rd t o fully

retracted posit ion.

(b ) At t a ch t es t l ea d s t o p in s 1 a n d 2 a n d n ot e

ohmmeter reading.

(c) I f con t i nu it y e xi st s , s w i t ch i s O K . R ep la c e

switch if meter indicates lack of continuity (switch

is open).

RED BRAKE WARNING LAMP

Th e r e d br a k e w a r n in g l ig h t w il l i l lum in a t e u n d er

the following conditions:

2-3 se con d s a t s t a r t -u p a s p a r t of n o r m a l bu lb

check.

When parking brakes are applied.

L ow b r a k e p ed a l ca u s ed b y l ea k i n f r on t /r ea r

brake hydraulic circuit .

I f t h e r e d l ig h t r e m a in s on a f t e r st a r t -u p , f ir st ver -

i f y t h a t t h e p a r k in g br a k e s a r e f u l ly r e le a se d . T h e n

ch eck p ed a l a ct ion a n d f luid leve l. A r e d l ig h t p lu slow p ed a l in d ica t e s t h e p r essu r e d if f er e n t ia l sw it ch

a n d va lve h a ve be e n a ct u a t e d d u e t o a sy st e m le a k .

O n m o d el s w i t h AB S b r a k es , t h e a m b er w a r n i n g

lig h t o n ly i l lu m in a t e s w h e n a n AB S m a lf u n ct io n h a s

occurred. The ABS light opera tes independently of

t h e r e d w a r n in g l ig h t .

For a ddit ion informa tion refer to G roup 8W.

MASTER CYLINDER/POWER BOOSTER

(1) S t a r t e n gin e a n d ch e ck boost e r va cu u m h ose

connections. A hissing noise indicates vacuum leak.

Correct any vacuum leak before proceeding.

(2) S t op e n g in e a n d sh ift t r a n sm ission in t o N e u -t r a l .

(3) Pu m p br a k e p e d a l u n t i l a l l va cu u m r e se r ve in

booster is depleted.

(4) P r es s a n d h ol d b r a k e p ed a l u n d er l ig h t f oot

p r essu r e. Th e p ed a l sh ou ld h old f irm , i f t h e p ed a l

f a l ls a w a y m a s t e r cy l in d er i s f a u l t y (i n t er n a l l ea k -

age).

(5) S t a r t e ng in e a n d n ot e p ed a l a c t ion i t s h ou ld

fall away slightly under light foot pressure then hold

firm. If no pedal action is discernible, power booster,

Fig. 6 Stop Lamp Switch Terminal Identification

TERMINAL PINSP LU NGE R T ES TPOSITIONS

5 - 8 BRAKES XJ



9/38

vacuum supply, or vacuum check valve is faulty. Pro-

ceed t o th e P OWER B OOSTER VACU UM TES T.

(6) If t h e P O WE R B O OS TE R VAC U U M TE S T

p a sses, r e bu ild boost e r va cu u m r e se r ve a s f ol low s:

Re le a se br a k e p e d a l . I n cr e a se e n g in e sp e e d t o 1500

r p m , close t h e t h r o t t le a n d im m ed ia t e ly st o p t u r n of f

ignit ion to stop engine.(7) Wa it a m in im u m of 90 secon d s a n d t r y br a k e

action a gain. B ooster should provide two or more vac-

u u m a ssist e d p e d a l a p p lica t io n s. I f va cu u m a ssist is

not provided, booster is faulty.

POWER BOOSTER VACUUM TEST

(1) Connect vacuum gauge to booster check valve

with short length of hose and T-fit t ing (Fig. 7).

(2) Start and run engine at curb idle speed for one

minute.

(3) Observe the vacuum supply. If vacuum supply

is not adequate, repair vacuum supply.

(4) C la m p h ose sh u t bet w e e n va cu u m so u r ce a n dcheck valve.

(5) Stop engine and observe vacuum gauge.

(6) I f v a cu u m d r op s m or e t h a n on e i n ch H G (33

m illiba r s) w it h in 15 se con d s, boost e r d ia p h r a g m or

check valve is faulty.

POWER BOOSTER CHECK VALVE TEST

(1) Disconnect vacuum hose from check valve.

(2) R em ov e ch eck v a lv e a n d v a lv e s ea l f rom

booster.

(3) U se a h a n d o p e r a t e d va cu u m p u m p f o r t e st .

(4) Ap pl y 15-20 i n ch es v a cu u m a t l a r g e e nd of

check valve (Fig. 8).

(5) Vacuum should hold steady. If gauge on pump

i nd ica t e s v a cu um l os s, ch eck v a lv e i s f a ul t y a n d

should be replaced.

COM BINATION VALVE

PRESSURE DIFFERENTIAL SWITCH

(1) H a ve h e lp e r si t in d r ive r s se a t t o a p p ly br a k e

p e d a l a n d o bse r ve r e d br a k e w a r n in g l ig h t .

(2) Raise vehicle on hoist .

(3) C o n ne ct blee d h ose t o a r e a r w h e e l cy l in d e r

a n d im m er se h o se e n d in con t a in er p a r t ia l ly f il led

w it h br a k e f lu id .

(4) Ha ve helper press an d hold bra ke pedal to floor

a n d o bse r ve w a r n in g l ig h t .

(a ) I f w a r n in g l ig h t i l lum in a t e s, sw it ch is o pe r a t -ing correctly.

(b) If light fails to illuminate, check circuit fuse,

bu lb, a n d w ir in g . Th e p a r k in g br a k e sw it ch ca n be

u sed t o a id in id e n t if y in g w h e t h er or n ot t h e br a k e

light bulb and fuse is functional. Repair or replace

p a r t s a s n ece ss a r y a n d t e st d if fe re nt i a l p res s ur e

sw it ch o p er a t io n a g a in .

(5) I f w a r n in g l ig h t s t il l d oes n ot i ll um in a t e,

switch is faulty. Replace combination valve assembly,

b lee d b r a k e s y s t em a n d v er i fy p rop er s w i t ch a n d

valve operation.

REAR PROPORTIONING VALVETh e va lve con t r o ls f luid f low . I f f luid e n t er s t h e

v a l v e a n d d oe s n ot e xi t t h e v a l ve t h e com b in a t i on

valve must be replaced.

DISC BRAKE ROTOR

The rotor bra king surfa ces should not be refinished

unless necessary.

L ig h t su r f a ce r u st a n d sca le ca n be r e m oved w it h a

l a t h e e q ui pp ed w i t h d u a l s a n d i ng d i scs . Th e r ot or

surfaces can be restored by machining in a disc brake

la t h e i f su r f a ce sco r in g a n d w e a r a r e l ig h t .

Fig. 7 Typical Booster Vacuum Test Connections

TEE FITTINGSHORT CONNECTINGHOSE CHECK VALVECHECK VALVEHOSECLAMPTOOL INTAKE MANI-FOLDVACUUM GAUGE

Fig. 8 Vacuum Check Valve And Seal

BOOSTER CHECK VALVE APPLY TEST VACUUM HEREVALVE SEAL

XJ BRAKES 5 - 9



10/38

Replace the rotor under the following conditions:

severely scored

tapered

h a r d sp o t s

cracked

below minimum thickness

ROTOR MINIMUM THICKNESS

Mea su r e r o t or t h ick n ess a t t h e ce n t er of t h e br a k e

shoe contact surface. Replace the rotor if worn below

m in im um t h ick n ess, or i f m a ch in in g w o u ld r e d uce

thickness below the allowable minimum.

Rot o r m in im u m t h ick n ess is u su a lly sp ecif ied on

the rotor hub. The specification is either stamped or

ca st in t o t h e h u b su r f a ce .

ROTOR RUNOUT

C h eck r ot or l a t er a l r u nou t w i t h d ia l i nd ica t or

C-3339 (Fig. 9). Excessive lat eral runout will cause

br a k e p e d a l p u lsa t io n a n d r a p id , u n e ve n w e a r o f t h eb ra k e s h oes . P o si t ion t h e d ia l i nd ica t or p lu n ger

approximately 25.4 mm (1 in.) inward from the rotor

edge.

NOTE: Be sure wheel bearing has zero end playbefore checking rotor runout.

M a x im u m a l l ow a b l e r ot or r u n ou t i s 0. 102 m m

(0.004 in.).

ROTOR THICKNESS VARIATION

Variations in rotor thickness will cause pedal pul-

sation, noise and shudder.

Me a su r e r o t o r t h ick n e ss a t 6 t o 12 p o in t s a r o u n d

the rotor face (Fig. 10).

Posit ion the micrometer approximately 25.4 mm (1

in.) from the rotor outer circumference for each mea-

surement.

Thickness should not vary by more tha n 0.013 mm(0.0005 in.) from point-to-point on the rotor. Machine

or replace the rotor if necessary.

BRAKE DR UM

Th e m a x im u m a l low a b l e d ia m et er of t h e d r um

b ra k in g s ur fa c e i s s t a m ped or ca s t i nt o t h e d ru m

o u t e r e d g e . G e n e r a l ly , a d r u m ca n be m a ch in e d t o a

m a x im u m of 1.52 m m (0.060 in .) o ve r siz e. Alw a y s

r ep la c e t h e d r u m i f m a c h in i ng w o ul d ca u s e d r um

d i a m et e r t o e xce ed t h e s iz e l im i t i n di ca t e d on t h ed r u m .

BRAKE DRUM RUNOUT

Me a su r e d r u m d ia m e t e r a n d r u n o u t w it h a n a ccu -

r a t e g a u g e. Th e m o st a ccu r a t e m e t h od of m e a su r e-

m e nt i n vol ve s m o un t i ng t h e d r u m i n a b r a k e l a t h e

a n d ch eck in g v a r i a t i on a n d r u n ou t w i t h a d i a l i n d i-

cator.

Va r i a t i on s i n d r u m d i a m et e r s h ou ld n ot e xce ed

0.076 mm (0.003 in.). Drum runout should not exceed

0.20 mm (0.008 in.) out of round. Machine the drum

if r u n ou t or va r ia t io n e xcee d t h e se va lu es. Re pla ce

the drum if machining causes the drum to exceed themaximum allowable diameter.

BRAKE LINE AND HOSES

F le x ible r u bbe r h o se is u se d a t bo t h f r o n t br a k e s

and at the rear axle junction block. Inspect the hoses

w h en ev er t h e b ra k e s ys t em i s s er vi ced , a t ev er y

e n g in e o i l ch a n g e , o r w h e n e ve r t h e ve h icle is in f o r

service.

Inspect the hoses for surface cracking, scuffing, or

w o r n sp ot s. Re pla ce a n y br a k e h o se im m e d ia t e ly i f

Fig. 9 Checking Rotor Runout And ThicknessVariation

DIAL INDICATOR

Fig. 10 Measuring Rotor Thickness

MICROMETERTAKE MINIMUM OF 6MEASUREMENTSAROUND ROTORROTOR

5 - 1 0 BRAKES XJ



11/38

the fabric casing of the hose is exposed due to cracks

or abrasions.

Also check brake hose installat ion. Faulty installa-

t ion ca n r e su lt in k in k ed , t w ist e d h ose s, or con t a ct

w i t h t h e w h e el s a n d t i r es or ot h er ch a s s is com po-

n e n t s. All of t h e se con d it ion s ca n lea d t o scu f fin g ,

cra ck in g a n d e ven t u a l f a i lu r e.The steel brake lines should be inspected periodi-

cally for evidence of corrosion, twists, kinks, leaks, or

other damage. Heavily corroded lines will eventually

r u st t h r o u g h ca u sin g le a k s. I n a n y ca se , co r r o d e d o r

damaged brake lines should be replaced.

Factory replacement brake lines and hoses are rec-

ommended t o ensure qua lity, correct length a nd supe-

r io r f a t ig u e l i f e . C a r e sh o u ld be t a k e n t o m a k e su r e

t h a t b r a k e l i n e a n d h o s e m a t i n g s u r f a c e s a r e c l e a n

a n d f r e e f r o m n ick s a n d bu r r s. Also r e m e m be r t h a t

r ig h t a n d lef t br a k e h o ses a r e n ot in t e rch a n g ea ble .

Use new copper seal washers at all caliper connec-

t ion s. B e su r e br a k e l in e con n e ct ion s a r e p r op er lym a d e (n ot cross t h r e a d e d ) a n d t ig h t e n ed t o r e com -

mended torque.

BRAKE FLUID CONTAMINATION

I n d ica t io n s of f luid con t a m in a t ion a r e sw o llen or

deteriorated rubber parts.

S w ol len r ub ber pa r t s i nd ica t e t h e pr es en ce of

petroleum in the brake fluid.

To t e st f or con t a m in a t ion , p u t a sm a ll a m o u n t of

d r a in e d br a k e f lu id in cle a r g la ss ja r . I f f lu id se p a -

r a t e s in t o la y e r s, t h e r e is m in e r a l o i l o r o t h e r f lu id

con t a m in a t ion of t h e br a k e f lu id .

I f b ra k e f lu id i s con t a m in a t ed , d r a in a n d t h or -oughly flush system. Replace master cylinder, propor-

t i on i ng v a l ve , ca l i pe r s ea l s , w h e el cy l in d er s ea l s ,

An t il ock B r a k es h y dr a u li c u n it a n d a l l h y dr a u li c

fluid hoses.

SERVICE PROCEDURES

BRAKE FLUID LEVEL

Always clean the master cylinder reservoir and cap

before adding fluid. This w ill prevent dirt from fall-

i ng i n t h e r es er voi r a n d con t a m in a t in g t h e b ra k e

fluid.T h e r e se r vo ir h a s a AD D a n d a F U L L m a r k o n t h e

sid e (F ig . 11) fi l l t o t h e F U L L m a r k .

MASTER CYLINDER BLEEDING

A new ma ster cylinder should be bled before insta l-

lat ion on t he vehicle. Required bleeding tools include

ble e d t u be s a n d a w o o d d o w e l t o st r o k e t h e p ist o n s.

B le ed t u bes ca n be f a br ica t e d f r om br a k e l in e.

BLEEDING PROCEDURE

(1) Mount master cylinder in vise.

(2) At t a c h b le ed t u b es t o cy li n der ou t l et p or t s .

Th e n p osit ion e a ch t u be e n d in t h e r e se r voir f luid

compartment (Fig. 12).(3) Fill reservoir with fresh brake fluid.

(4) Press cylinder pistons inward with wood dowel.

Then release pistons and allow them to return under

spring pressure. Continue bleeding operations until

a ir bu bbles a r e n o lon g er visible in t h e f luid r e se r-

voir.

BRAKE BLEEDING

U s e M op a r b r a k e f lu id , or a n eq u iv a l en t q u a l it y

f lu id m ee t in g S AE J 1703-F a n d D O T 3 s t a n d a r d s

only. Use fresh, clean fluid from a sealed container at

a l l t im e s.

D o n ot pu m p t h e b r a k e ped a l a t a n y t i me w h il e

blee d in g . Air in t h e sy st e m w il l be com p r essed in t o

s m a l l b u bb le s t h a t a r e d is t r ib u t ed t h r ou g hou t t h e

hydraulic system. This will make addit ional bleeding

operations necessary.

Do not allow the master cylinder to run out of f luid

during bleed operations. An empty cylinder will allow

Fig. 11 Master Cylinder Fluid Level

FLUIDLEVELMARKS RESERVOIR

Fig. 12 Master Cylinder Bleeding

BLEEDINGTUBES RESERVOIR

XJ BRAKES 5 - 1 1



12/38

a d d it ion a l a ir t o be d r a w n in t o t h e sy st e m . C h e ck t h e

cy li nd er f lu id l ev el f req u en t ly a n d a d d f lu id a s

needed.

Bleed only one brake component at a t ime. Recom-

mended bleed sequence is:

master cylinder

combination valve r ig h t r e a r w h e e l

lef t r e a r w h e e l

right front wheel

left front wheel

MANUAL BLEEDING

(1) Remove reservoir filler caps an d fill reservoir

with Mopar, or equivalent quality DOT 3 brake fluid.

(2) If calipers, or wheel cylinders were overhauled,

op en a l l ca l i pe r a n d w h e el cy l in d er b lee d s cr ew s .

Th e n close e a ch blee d scr ew a s f luid st a r t s t o d r ip

from it . Top off ma ster cylinder reservoir once more

before proceeding.(3) At t a ch on e e n d of blee d h ose t o blee d scr e w

a n d in ser t op posit e e n d in g la ss con t a in e r p a r t ia l ly

filled with brake fluid (Fig. 13). Be sure end of bleed

hose is immersed in fluid.

(4) Op en u p b le ed er, t h en h a v e a h el pe r p re ss

d o w n t h e br a k e p e d a l . O n ce t h e p e d a l is d o w n clo se

t h e b le ed er. R ep ea t b lee di n g u n t il f lu id s t r ea m i s

cl ea r a n d f r ee of b ub bl es . Th en m ov e t o t h e n ex t

wheel.

PRESSURE BLEEDING

I f p r essu r e blee d in g e q u ip m en t w il l be u sed , t h e

f r on t br a k e m e t e r in g va lve w il l h a ve t o be h e ld o pe n

t o ble e d t h e f r o n t br a k e s. T h e va lve st e m is lo ca t e d

i n t h e f or w a r d e nd of t h e com b in a t i on v a l ve . Th e

st e m m u st e it h e r be p r e sse d in w a r d , o r h e ld o u t w a r d

slightly. a spring clip tool or helper is needed t o hold

the valve stem in posit ion.

F o llow t h e m a n u f a ct u r e r s in st r u ct ion s ca r e f u lly

w h e n u sin g p r e ssu r e e q u ipm e n t . D o n o t e xcee d t h e

tank manufacturers pressure recommendations. Gen-erally, a ta nk pressure of 15-20 psi is sufficient for

bleeding.

F il l t h e ble e d e r t a n k w it h r e co m m e n d e d f lu id a n d

purge air from the tank lines before bleeding.

Do not pressure bleed without a proper master cyl-

in d e r a d a p t e r . T h e w r o n g a d a p t e r ca n le a d t o le a k -

a g e , o r d r a w in g a ir ba ck in t o t h e sy st e m .

DISC ROTOR MACHINING

Rot o r br a k in g su r f a ces ca n be sa n d e d or m a ch in ed

in a d isc br a k e la t h e .

Th e l a t h e m u s t m a c h in e b ot h s id es of t h e r ot or

s i mu lt a n e ou s ly w i t h d u a l (t w o ) c ut t e r h ea d s (F i g.14). E quipment capa ble of ma chining only one side a t

a t ime will produce a tapered rotor.

Th e la t h e sh ou ld a lso be e q u ipp ed w it h a g r in d er

a t t a ch m e n t o r d u a l sa n d in g d iscs f o r f in a l clea n u p or

light refinishing (Fig. 15).

I f t h e r ot o r su r f a ces on ly n e ed m in or cle a n u p o f

r u s t , s ca l e, or m i n or s cor i ng , u s e a b r a s i ve d is cs t o

clean up the rotor surfaces. However, when a rotor is

sco r e d o r w o r n , m a ch in in g w it h cu t t in g t o o ls w il l be

required.

CAUTION: Do not machine the rotor if it will cause

the rotor to fall below minimum allowable thick-ness.

BRAKE DRUM M ACHINING

Th e br a k e d r u m s ca n be m a ch in ed o n a d r u m la t h e

wh en necessary. Init ial m achining cuts sh ould be lim-

ited to 0.12 - 0.20 mm (0.005 - 0.008 in.) at a t ime as

h ea v i er f ee d r a t e s ca n p rod u ce t a p er a n d s u r fa c e

v a r i a t i on . F i n a l f in i sh cu t s of 0. 025 t o 0. 038 m m

(0.001 to 0.0015 in.) are recommended and will gen-

erally provide the best surface finish.

B e su r e t h e d r u m is se cu r e ly m o u n t e d in t h e la t h e

before machining operations. A damper strap shoulda lw a y s be u se d a r o u n d t h e d r u m t o r e d u ce vibr a t io n

a n d a vo id ch a t t e r m a r k s.

Th e m a x im u m a l low a b l e d ia m et er of t h e d r um

b ra k in g s ur fa c e i s s t a m ped or ca s t i nt o t h e d ru m

ou t er e dg e. Al w a y s r ep la c e t h e d r u m i f m a c h in i ng

w o u ld ca u se d r u m d ia m e t e r t o e x ce e d t h e siz e l im it

in d ica t e d o n t h e d r u m .

BRAKE LI NE

Mopar preformed m etal brake line is recommended

a n d p r ef er r e d f or a l l r e pa ir s . H o w e ve r, d ou ble -w a ll

Fig. 13 Bleed Hose Setup

BLEED HOSEFLUID CON-TAINER PAR-TIALLY FILLEDWITH FLUID

5 - 1 2 BRAKES XJ

SERVICE PROCEDURES (Continued)


13/38

steel line can be used for emergency repair when fac-

t o r y r e pla cem e n t p a r t s a r e n ot r e a d ily a va i la ble .

S peci a l, h ea v y d ut y t u be b en d in g a n d f la r i ng

e q u ip m e n t is r e q u ir e d t o p r e p a r e d o u ble w a ll br a k e

line. Special bending tools are needed to avoid kink-

in g o r t w ist in g m e t a l br a k e l in e . I n a d d it io n , sp e cia l

flaring tools are needed to provide the inverted-type,

double flare required on metal brake lines.

FLARING PROCEDURE

(1) Cut off da ma ged tube w ith Tubing Cutt er.

(2) R ea m cu t ed g es of t u b in g t o e ns u r e p rop er

flare.

(3) Install replacement tube nut on section of tube

to be repaired.

(4) I n se r t t u be in f la r in g t o ol . C e n t e r t u be in a r e abetween vertical posts.

(5) P la ce g a u g e f or m over t h e e n d of t h e t u be .

(6) P u s h t u b in g t h r ou g h f la r i n g t ool ja w s u n t il

t u be co n t a ct s r e ce sse d n o t ch in g a u g e t h a t m a t ch e s

tube diameter.

(7) S q u eez e f la r i n g t ool ja w s t o l ock t u b in g i n

place.

(8) I n se r t p lu g o n g a u g e in t h e t u be . T h e n sw in g

compression disc over gauge and center tapered flar-

ing screw in recess of compression disc (Fig. 16).

(9) Tighten t ool ha ndle until plug gauge is seat ed

on ja w s of f la r in g t o ol . Th is w ill s t a r t t h e in ver t e d

flare.(10) Re mov e t h e p lu g g a u g e a n d com p le t e t h e

inverted flare.

(11) Rem o ve t h e f la r in g t o ols a n d ver ify t h a t t h e

inverted flare is correct .

REMOVAL AND INSTALLATION

STOP LAMP SWITCH

REMOVAL

(1) Remove steering column cover and lower tr im

panel for switch access (if necessary).

(2) P r es s b r a k e p e da l d ow n w a r d t o f ul ly a p pl ie d

position.

Fig. 14 Rotor Refinishing

BRAKINGDISC DAMPERCUTTINGTOOLS

Fig. 15 Rotor Grinder

BRAKING DISCGRINDER

Fig. 16 Inverted Flare Tools

XJ BRAKES 5 - 1 3

SERVICE PROCEDURES (Continued)


14/38

(3) Rot a t e sw it ch a p p r ox im a t e ly 30 in cou n t e r-

clockwise direction to unlock sw itch retainer. Then

p u ll sw it ch r e a r w a r d a n d o u t o f br a ck e t .

(4) D i scon n ect s w i t ch w i r e h a r n es s a n d r em ov e

switch from vehicle (Fig. 17).

INSTALLATION

(1) P u l l s w it ch pl un g er a l l t h e w a y ou t t o f ul ly

extended position.

(2) C on n e ct h a r n e ss w ir e s t o sw it ch .

(3) Press and hold brake pedal in applied posit ion.

(4) I n st a l l sw it ch a s f ol low s: Alig n t a b on sw it ch

w it h n o t ch in sw it ch br a ck e t . T h e n in se r t sw it ch in

br a cke t a n d t u r n i t clockw ise a bou t 30 t o lock i t in

place.

(5) Release brake pedal. Then pull pedal fully rear-w a r d . P e d a l w i l l s e t p lu n g er t o cor r ect p os it i on a s

p ed a l p u sh e s p lu n g er in t o sw it ch bod y. S w it ch w il l

m a k e r a t ch e t in g so u n d a s i t se l f a d ju st s .

BRAKE PEDAL

REMOVAL

(1) Re m ove k n ee block er u n d er t h e st e er in g col-

u m n .

(2) Remove r etainer clip securing booster push rod

to pedal (Fig. 18).

(3) Remove stop lamp switch.

(4) Remove nuts securing the booster to the pedalsu pp or t br a cke t a n d n u t s t o t h e colu m n br a ck et .

(5) R em ov e ped a l a n d s uppor t b ra ck et a s a n

assembly from the vehicle.

INSTALLATION

(1) I n st a l l p e d a l a n d su p p o r t br a ck e t a s a n a sse m -

bly into the vehicle.

(2) I n st a l l n u t s se cu r in g t h e bo o st e r t o t h e p e d a l

su pp or t br a cke t a n d n u t s t o t h e colu m n br a ck et .

(3) Tighten nuts to 39 Nm (29 ft . lbs.).

(4) In s ta l l b oos t er pu sh r od on p ed a l pi n a n d

install new retainer clip.

(5) Install knee blocker.

COM BINATION VALVE

NOTE: The combination valve is not repairable. Thevalve is serviced as an assembly only.

REMOVAL

(1) Remove a ir clean er cover a nd hose for a ccess to

valve.

(2) Unsnap connector lock tabs and disconnect dif-

f er e n t ia l p r essu r e sw it ch w ir e a t com bin a t ion va lve

(Fig. 19). Do not pull switch wire to disconnect .

Fig. 17 Stop Lamp Switch

RETAINER TERMINALSSWITCHPLUNGER

Fig. 18 Booster Push Rod

BRAKEPEDAL BOOSTER RODBUSHING

Fig. 19 Differential Pressure Switch

SWITCH TERMI-N AL C OM BI NAT ION VALVEWIRE HARNESS CON-NECTOR

5 - 1 4 BRAKES XJ

REMOVAL AND INSTALLATION (Continued)


15/38

(3) D iscon n e ct br a k e l in es a t com bin a t ion va lve

(Fig. 20).

(4) Remove mounting nut and remove valve.

INSTALLATION

(1) I n s t a l l v a l ve a n d t i g ht e n m o u nt i n g n u t t o 1 7

Nm (155 in. lbs.).

(2) Connect brake lines to replacement valve. Start

l in e f i t t in g s by h a n d t o a vo id cr o ss t h r e a d in g .

(3) Tighten brake line fit t ings to 19 Nm (170 in.

lbs.).

(4) Connect wire to pressure differential switch.

(5) Bleed brakes.

MASTER CYLINDER

REMOVAL

(1) On R HD vehicles remove the coolant reserve/

overflow tank. Refer to Group 7 Cooling System.

(2) R em ov e b r a k e l in es a t m a s t e r cy l in d er a n d

combination valve (Fig. 20).

(3) D iscon n e ct d i ff er e n t ia l p r essu r e sw it ch w ir e

from the combination valve.

(4) Rem ove m ou n t in g n u t s f r om t h e com bin a t ion

valve bracket and remove the valve (Fig. 20).

(5) Re m o ve m o u n t in g n u t s f r o m t h e m a st e r cy l in -

der.

(6) Remove ma ster cylinder.(7) Remove cylinder cover and drain fluid.

(8) I f m a st e r cy l in d e r r e ser voir r e q u ir e s ser vice ,

refer to reservoir replacement procedure in this sec-

tion.

INSTALLATION

NOTE: Bleed master cylinder on bench before

installation.

(1) Remove protective sleeve from primary piston

sh a n k on n e w m a st e r cyl in de r.

(2) C lea n cy li nd er m ou nt i ng s ur fa ce of b ra k e

booster.

(3) I n s t a l l m a s t e r cy li n der on t o b r a k e b oos t er

studs.

(4) I n st a l l m o u n t in g n u t s a n d t ig h t e n t o 17.5 N m(155 in. lbs.).

(5) I n st a l l com bin a t ion va lve a n d in st a l l m o u n t in g

n u t s.

(6) C on n ect b r a k e l in es t o m a s t e r cy l in d er a n d

com b in a t i on v a l ve a n d t i gh t en t o 19 N m (170 i n .

lbs.).

(7) Connect differential pressure switch w ire to the

combinat ion valve.

(8) O n RH D veh icles in st a l l t h e coola n t r e ser ve/


(9) F il l a n d blee d br a k e sy st e m .

POWER BRAKE BOOSTER

REMOVAL

(1) On R HD vehicles remove the coolan t reserve/


(2) Disconnect brake lines at master cylinder.

(3) Disconnect wire a t combinat ion valve differen-

t ia l p r essu r e sw it ch .

(4) R em ov e n u t m ou n ti ng com bi na t i on v a lv e

bracket to booster studs and remove valve.

(5) R em ov e n u t s m ou n t in g m a s t er cy li nd er t o

booster studs and remove cylinder.

(6) D iscon n e ct va cu um h ose f r om boost e r ch eck

valve.(7) Re m o ve k n ee blocke r u n d er t h e st e er in g col-

u m n .

(8) R em ov e r et a i n i ng cl ip t h a t s ecu r es b oos t er

push rod to brake pedal (Fig. 21).

(9) R e m ov e n u t s a t t a ch i ng b oos t er t o p a s se ng er

compartment side of dash panel (Fig. 22).

Fig. 20 Combination Valve

COMBINATION VALVE MASTER CYLINDER

Fig. 21 Booster Push Rod

BRAKEPEDAL BOOSTER RODBUSHING

XJ BRAKES 5 - 1 5



16/38

(10) I n e n gin e com p a r t m e n t , s l id e boost e r st u d s

ou t of d a sh p a n e l, t i lt boost e r u p w a r d , a n d r e m ovebooster from engine compartment.

(11) Remove dash seal from booster.

INSTALLATION

(1) Install dash seal on booster.

(2) Align and posit ion booster on dash panel.

(3) I n p a s sen g er com p a r t m en t , i n st a l l b oos t er

m ou n t in g n u t s . Ti gh t en n u t s ju s t en ou g h t o h ol d

booster in place.

(4) S l id e boost e r p u sh r od on t o t h e br a k e p ed a l .

Th en s ecu r e p us h r od t o p ed a l p in w i t h r et a i n i ng

clip.

NOTE: Lubricate the pedal pin and bushing withMopar multi-mileage grease before installation.

(5) Tighten booster mounting nuts to 39 Nm (29

ft. lbs.).

(6) Install the knee blocker.

(7) I f or ig in a l m a st e r cyl in de r is bein g in st a l led ,

ch eck con d it ion of se a l a t r e a r of m a st e r cyl in de r.

Replace seal if cut , or torn.

(8) C l ea n cy li nd er m ou n t in g s ur fa c e of b ra k e

booster. Use shop towel wett ed wit h bra ke cleaner for

t h is p u r p o se . D ir t , g r e a se , o r sim ila r m a t e r ia ls w il l

p r even t p r op er cyl in d e r se a t in g a n d cou ld r e su lt invacuum leak.

(9) Alig n a n d in st a l l m a st e r cy l in d e r on boost e r

st u d s. I n st a l l m ou n t in g n u t s a n d t ig h t e n t o 17.5 N m

(155 in. lbs.).

(10) Connect vacuum hose to booster check valve.

(11) Connect and secure brake lines to combination

v a l ve a n d m a s t e r cy l in d er. S t a r t a l l b r a k e l in e f i t -

t in g s by h a n d t o a vo id cr o ss t h r e a d in g .

(12) I n st a l l com bin a t ion va lve on boost e r st u d s.

Tighten bracket m ounting nut s to 17.5 Nm (155 in.

lbs.).

(13) Connect wire to combination valve switch.

(14) O n RH D ve hicles in st a l l t h e coola n t r e ser ve/


(15) Fill and bleed brake system.

(16) Verify proper brake operation before moving

vehicle.

DISC BRAKE CALIPER

REMOVAL

(1) Raise and support vehicle.

(2) Remove front wheel and t ire assembly.

(3) D r a in sm a ll a m o u n t o f f lu id f r o m m a st e r cy lin -

der brake reservoir with suction gun.

(4) B o t t o m ca l ip er p ist on in bor e w it h C -cla m p .

P os i t ion cl a m p s cr ew on ou t b oa r d b r a k e s h oe a n d

cl a m p f r a m e on r ea r of ca l i pe r (F i g. 23). Do notallow clamp screw to bear directly on outboardshoe retainer spring. Use wood or metal spacer

between shoe and clamp screw.

(5) Re m ove br a k e h o se m o u n t in g bolt a n d d isca r d

washers (Fig. 24).

(6) Remove caliper mounting bolts (Fig. 25).

(7) Tilt t op of caliper outwa rd with pry t ool if n ec-

essary (Fig. 26) and remove caliper.

(8) Remove caliper from vehicle.

INSTALLATION(1) C l e a n b r a k e s h oe m ou n t in g l ed g es w i t h w i r e

br u sh a n d a p p ly l igh t coa t of Mop a r m u lt i-m ilea g e

grease to surfaces (Fig. 27).

(2) C on n ect b ra k e h os e t o ca l iper w i t h neww a sh e r o n bo t h sid e s o f h o se f i t t in g . D o n o t t ig h t e n

fit t ing bolt completely at this t ime.

(3) Install caliper by posit ion notches at lower end

of b r a k e s h oe s on b ot t om m ou n t in g l ed g e. Th en

r ot a t e ca l ipe r o ver r ot o r a n d se a t n ot ch es a t u p pe r

end of shoes on top mounting ledge (Fig. 28).

Fig. 22 Booster Mounting

BOOSTER

Fig. 23 Bottoming Caliper Piston With C-Clamp

CALIPERBOSSOUTBOARDBRAKESHOE C-CLAMP

5 - 1 6 BRAKES XJ



17/38

(4) C oa t ca l iper m ou nt i ng b ol t s w i t h s il icon e

g r ea se . Th e n in st a l l a n d t ig h t en bolt s t o 15 N m (11

ft. lbs.).

CAUTION: If new caliper bolts are being installed,or if the original reason for repair was a drag/pullcondition, check caliper bolt length before proceed-ing. Bolts must not have a shank length greater

than 67.6 mm (2.66 in.) (Fig. 29).

(5) Tighten brake hose fitting bolt to 31 Nm (23 ft.

lbs.).

CAUTION: Insure the brake hose is not twisted or

kinked and clear of all steering and suspensioncomponents.

(6) I n st a l l w h e e l a n d t ir e a ssem bly.

(7) Remove support and lower vehicle.

(8) P u m p b r a k e p ed a l u n t il ca l i pe r p is t on s a n d

br a k e sh o es a r e se a t e d .

(9) F il l m a st e r cy l in d e r a n d blee d br a k e sy st e m .

DISC BRAKE SHOES

REMOVAL

(1) Raise and support vehicle.

(2) Remove wheel and t ire assembly.

(3) Remove caliper.

(4) P r es s in g on e e nd of ou t b oa r d s h oe i n w a r d t o

d isen g a g e sh oe lu g . Th e n r o t a t e sh oe u p w a r d u n t i l

r e t a in er sp r in g cle a r s ca l ip er . P r e ss op posit e e n d of

shoe inward to disengage shoe lug and rotate shoe up

and out of caliper (Fig. 30).

(5) G r a sp e n d s o f in boa r d sh oe a n d t i l t sh o e o ut -

ward to release springs from caliper piston (Fig. 31)

and remove shoe from caliper.

Fig. 24 Brake Hose And Bolt

FITTINGWASHERSCALIPERS

Fig. 25 Caliper Mounting Bolts

CALIPERMOUNTERBOLT (2)CALIPER

Fig. 26 Caliper Removal

TILT CALIPEROUTBOARD TOREMOVE

Fig. 27 Caliper Lubrication Points

BUSHINGSCALIPER

MOUNTING

BOLTS

MOUNTINGLEDGES

XJ BRAKES 5 - 1 7



18/38

NOTE: If original brake shoes will be used, keepthem in sets left and right. They are not inter-changeable.

(6) S e cur e ca l ip er t o n e a r by su spe n sion p a r t w it h

wire. Do not allow brake hose to support caliperweight.

(7) Wipe caliper off with shop rags or towels.

CAUTION: Do not use compressed air, this can

unseat dust boot and force dirt into piston bore.

INSTALLATION

(1) I n st a l l in bo a r d sh o e in ca l ip e r a n d ve r if y sh o e

r e t a in in g is f u lly se a t e d in t o t h e p ist o n.

(2) S t a r t in g on e e n d of ou t boa r d sh oe in ca l ip er

a n d r o t a t in g sh o e d o w n w a r d in t o p la ce . V e r if y sh o e

lo ca t in g lu g s a n d sh o e sp r in g a r e se a t e d .

(3) Insta ll ca liper.

(4) I n st a l l w h e e l a n d t ir e a ssem bly.

(5) Remove support and lower vehicle.

(6) P u m p b r a k e p ed a l u n t il ca l i pe r p is t on s a n d

br a k e sh o es a r e se a t e d .

(7) Top off bra ke fluid level if necessa ry.

DISC BRAKE ROTOR

REMOVAL

(1) Remove wheel and t ire assemble.

(2) Remove caliper.

(3) Re m ove r e t a in er s secur in g r ot o r t o h u b st u d s

(Fig. 32).

(4) Remove rotor from hub.

(5) I f r ot o r sh ield r e q u ir e s se rvice , r e m ove f r on t

h u b a n d be a r in g a sse m bly .

Fig. 28 Caliper Installation

TOP LEDGE BRAKESHOE TAB ON LEDGEOUTER SURFACELEDGE SEATED INBRAKESHOE NOTCHBOT TOMLEDGE

Fig. 29 Mounting Bolt Dimensions

CORRECT SHANK LENGTH:6 7 mm ( 0.6 mm)2.637 in. ( 0.0236in.)22 mm (0.866 in.)THREADLENGTHCALIPER BOLT

Fig. 30 Outboard Brake Shoe Removal

OUTBOARDBRAKESHOE SHOE SPRING LOCATING LUGCALIPERLOCATINGLUG

Fig. 31 Inboard Brake Shoe Removal

CALIPERPI STO N SH OE S PR IN GS I NBOA RD B RAK E-SHOE

5 - 1 8 BRAKES XJ



19/38

INSTALLATION

(1) If new rotor is being inst alled, remove protec-

t i ve coa t i n g f r om r ot or s u r fa c es w i t h ca r b u r et orcleaner.

(2) Install rotor on hub.

(3) Install caliper.

(4) I n st a l l n e w sp r in g n u t s o n w h e e l st u d s.

(5) I n st a l l w h e el a n d t ir e a ssem bly.

DRUM BRAKE SHOES

REMOVAL

(1) Raise vehicle and remove rear wheels.

(2) R em ov e a n d d is ca r d s pr in g n u ts s ecu r in g

d r u m s t o w h e e l st u d s.

(3) Re m o ve br a k e d r u m s. I f d r u m s p r o ve d if f icu ltt o r e m ove, r e t r a ct br a k e sh oe s. Re m o ve a cce ss p lu g

a t t h e r e a r of b a ck in g p la t e a n d b a ck of f a d ju st er

screw with brake tool and screwdriver.

(4) Re m ove U -clip a n d w a sh e r se cu r in g a d ju st er

cable to parking brake lever (Fig. 33).

(5) Re m ove p r im a r y a n d se con d a r y r e t u r n sp r in g s

from anchor pin with brake spring pliers.

(6) Remove hold-down springs, retainers and pinsw it h st a n d a r d r e t a in in g sp r in g t o o l .

(7) I n st a l l s pr i ng cl a m ps on w h e el cy li n der s t o

hold pistons in place.

(8) R em ov e a d ju s t er l ev er, a d ju s t er s cr ew a n d

spring.

(9) Remove adjuster cable and cable guide.

(10) Remove brake shoes and parking brake strut .

(11) Disconnect cable from parking brake lever and

remove lever.

INSTALLATION

(1) Clean support plate with brake cleaner.

(2) I f n e w d r u m s a r e bein g in st a l le d , r e m ove p r o-t e ct ive coa t in g w it h ca r bu r et o r cle a n e r f ol low e d by

f in a l r in se w it h br a k e clea n e r.

(3) C le a n a n d lu br ica t e a n ch o r p in w it h l ig h t co a t

of Mopar multi-mileage grease.

(4) Ap ply Mop a r m u lt i-m ilea g e g r ea se t o br a k e

shoe contact surfaces of support plate (Fig. 34).

(5) Lu b ri ca t e a d ju s t er s cr ew t h r ea d s a n d p iv ot

w it h sp r a y lu be .

(6) Attach parking brake lever to secondary brake

shoe. Use new washer and U-clip to secure lever.

(7) Remove w heel cylinder clam ps.

(8) Attach parking brake cable to lever.

Fig. 33 Drum Brake ComponentsTypical

RIGHT REAR BRAKEASSEMBLYADJUSTER LEVERADJUSTERCABLEHOLDDOWN SPRINGAND RETAINERS ADJUSTERLEVERSPRING TRAILING SHOE CYLINDER-TO-SUPPORT SEALHOLDDOWNPINSACCESSPLUGSSUPPORT PLATECABLE HOLE PLUGPARK BRAKE STRUTAND SPRINGADJUSTER SCREWASSEMBLYHOLDDOWNS PR IN G A NDRETAINERSLEADING SHOECABLEGUIDESHOE RETURNSPRINGS SHOE GUIDEPLATE PIN SHOESPRINGPARK BRAKELEVER

Fig. 32 Rotor & Hub

ROTOR RETAINERBEARING NUTNUT LOCKCOTTER PINWASHER

XJ BRAKES 5 - 1 9



20/38

(9) I n s t a l l b r a k e s h oe s on s u pp or t p la t e . S e cu r e

sh o e s w it h n e w h o ld - d o w n sp r in g s, p in s a n d r e t a in -

ers.(10) I n st a l l p a r k in g br a k e st r u t a n d sp r in g .

(11) I n st a l l g ui de pl a t e a n d a d ju st er ca b le on

anchor pin.

(12) I n st a l l p r im a r y a n d se con d a r y r e t u r n sp r in g s.

(13) I n s t a l l a d ju s t er ca b l e g u id e on s econ d a r y

shoe.

(14) Lubricate and assemble adjuster screw.

(15) I n st a l l a d ju st e r scr ew , sp r in g a n d leve r a n d

connect to adjuster cable.

(16) Adjust shoes to drum.

(17) I nsta ll w heel/tire assemblies a nd lower vehi-

cle.

(18) Verify firm brake pedal before moving vehicle.

WHEEL CYLINDER

REMOVAL

(1) Remove wheel and t ire assembly.

(2) Remove brake drum.

(3) Disconnect wheel cylinder bra ke line.

(4) Rem ove br a k e sh oe r e t u r n sp r in g s a n d m ove

shoes out of engagement with cylinder push rods.

(5) Re m ove cylin de r a t t a ch in g bolt s a n d r e m ove

cylinder from support plate.

INSTALLATION

(1) Apply bead of silicone sealer ar ound cylinder

mounting surface of support plate.

(2) I n st a l l cy l in d e r m o u n t in g bo lt s a n d t ig h t e n t o

correct torque.

(3) Connect brake line to cylinder.

(4) I n st a l l br a k e sh o e r e t u r n sp r in g .

(5) I n st a l l br a k e d r u m .

(6) I n st a l l w h e el a n d t ir e a ssem bly.

(7) Bleed brake system.

BRAKE SUPPORT PLATE

REMOVAL

(1) R em ov e w h e el a n d t i r e a s s em b ly a n d b r a k e

d r u m .

(2) Remove bra ke shoe a ssembly.

(3) R em ov e p a r ki n g b r a k e ca b l e f r om p a r ki n gbrake lever.

(4) C om pr es s p a r ki n g b r a k e ca b l e r et a i n er t a b s

with a hose clamp (Fig. 35). Then push retainer and

cable through and out of support plate.

(5) Disconnect brake line at wheel cylinder.

(6) Remove wheel cylinder from support plate.

(7) Remove axle shaft , refer to Group 3 for proce-

dures.

(8) Re m ove bo lt s a t t a ch in g su pp or t p la t e t o a x le

and remove support plate.

INSTALLATION

(1) Ap pl y b ea d of s i li con e s ea l er a r ou n d a x l e

mounting surface of support plate.

(2) I n st a l l su pp or t p la t e on a x le f la n g e . Tig h t en

attaching bolts to 47-81 Nm (35-60 ft. lbs.).

(3) Apply bead of silicone sealer a round w heel cyl-

inder mounting surface and install wheel cylinder.

(4) Install brake line in wheel cylinder.(5) Install parking brake cable in support plate.

(6) I n st a l l a x le sh a f t , r e fe r t o G r ou p 3 f or p r oce -

dure.

(7) C o n n ect p a r k in g br a k e ca ble t o lever on se c-

ondary shoe and install brake shoes on support plate.

(8) Ad ju st br a k e sh o es t o d r u m w it h br a k e g a u g e .

(9) I n s t a l l b r a k e d r u m a n d w h e el a n d t i r e a s s em -

bly.

(10) Bleed brake system.

Fig. 34 Shoe Contact Surfaces

ANCHORPIN SUPPORTPLATESHOE CONTACTSURFACES

Fig. 35 Parking Brake Cable Removal

CABLEASSEMBLYCABLERETAINERAIRCRAFT TYPE HOSECLAMP

5 - 2 0 BRAKES XJ



21/38

REAR PARKING BRAKE CABLES

REMOVAL

(1) Ra ise ve h icle a n d loose n e q u a liz e r n u t s u n t i l

r e a r ca ble s a r e sla ck .

(2) Disengage cables from equalizer and compress

ca ble r e t a in e r s w it h a w o r m d r ive h o se cla m p .(3) Remove cables from the cable bracket (Fig. 36).

(4) Re m o ve r e a r w h e e l a n d br a k e d r u m s.

(5) Re m ove se con d a r y br a k e sh oe a n d d iscon n e ct

cable from lever on brake shoe.

(6) Compress cables retainer with worm drive hose

cl a m p (F i g. 37) a n d r em ov e ca b l es f r om b a ck in g

plates.

INSTALLATION

(1) I n s t a l l n ew ca b l es i n b a ck in g p la t e s . B e s u r e

ca ble r e t a in e r is se a t e d.

(2) At t a ch ca ble t o le ve r o n br a k e sh oe a n d in st a l l

brake shoe on backing plate.

(3) Ad ju st br a k e sh o es t o d r u m w it h br a k e g a u g e .

(4) I n st a l l br a k e d r u m s a n d w h e e ls.(5) I n st a l l ca ble s in t o t h e ca ble br a ck et a n d in su r e

r e t a in e r s a r e se a t e d in t h e br a ck e t .

(6) E n g a g e t h e ca b l e e n d s i n t o t h e e q ua l i zer a n d

in st a l l e q u a liz e r n u t .

(7) Adjust parking brakes.

PARKING BRAKE LEVER

The center console must be removed to service the

parking brake lever. Refer to Group 23 Interior Com-

ponents for service procedures.

REMOVAL

(1) Release parking brakes.(2) Raise vehicle.

(3) Remove adjusting nut from t ensioner rod at the

equalizer (Fig. 38).

(4) Lower vehicle.

(5) Disengage front cable from the cable lever.

(6) Compress cable retainer with worm drive hose

cla m p a n d r e m o ve t h e ca ble f r o m t h e p a r k in g br a k e

lever base.(7) D is con n ect p a r ki n g b r a k e l a m p s w i t ch w i r e

(Fig. 39).

(8) Re m ove p a r k in g br a k e lever a sse m bly m ou n t -

ing bolts (Fig. 39).

(9) Remove lever assembly.

(10) Remove parking brake lamp switch.

INSTALLATION

(1) I n st a l l p a r k in g br a k e la m p sw it ch .

(2) Posit ion lever assembly on floorpan and install

lever mounting bolts.

Fig. 36 Parking Brake Cables


Fig. 37 Cable Retainer

CABLERETAINER REARCABLEWORM DRIVEHOSE CLAMP

Fig. 38 Parking Brake Equalizer


XJ BRAKES 5 - 2 1



22/38

(3) I n s e r t f r on t ca b l e t h r ou g h t h e p a r ki n g b r a k e

l ev er b a s e. I n s u re t h e ca b l e r e t a i n er i s s ea t e d i n t o

t h e ba se .

(4) At t a ch t h e f r on t ca ble t o t h e ca ble lever (F ig .

39).

(5) C on n e ct p a r k in g br a k e la m p sw it ch w ir e.

(6) Raise vehicle.

(7) I n st a l l a d ju st in g n u t t o t h e t e n sio n e r r o d a n d

a d ju st p a r k in g br a k es.

(8) Lower vehicle.

(9) Verify correct parking brake operation.

DISASSEMBLY AND ASSEMBLY

MASTER CYLINDER RESERVOIR

REMOVAL

(1) R em ov e r es er v oi r ca p a n d e mp t y f lu id i n t o

drain container.

(2) R e m ov e p in s t h a t r et a i n r es er v oi r t o m a s t e r

cylinder. Use hammer and pin punch to remove pins

(Fig. 40).

(3) Clamp cylinder body in vise with brass protec-

t ive ja w s.

(4) Loosen r eservoir from grommets with pry tool

(Fig. 41).

(5) Remove reservoir by rocking it to one side and

pulling free of grommets (Fig. 42).

(6) Remove old grommets from cylinder body (Fig.

43).

INSTALLATION

CAUTION: Do not use any type of tool to installthe grommets. Tools may cut, or tear the grommets

creating a leak problem after installation. Install thegrommets using finger pressure only.

(1) Lubricate new grommets with clean brake fluid

and Install new grommets in cylinder body (Fig. 44).

U se f in g e r p r e ssu r e t o in st a l l a n d se a t g r o m m e t s.

(2) Sta rt reservoir in grommets. Then rock reser-

vo ir ba ck a n d f o r t h w h ile p r e ssin g d o w n w a r d t o se a t

it in grommets.

(3) I n s t a l l p in s t h a t r et a i n r es er v oi r t o cy l in d er

body.

Fig. 39 Parking Brake Lever Assembly

MOUNTING BOLTS FRONT CABLE LEVERPARKING BRAKE SWITCHPARKING BRAKELEVER

Fig. 40 Reservoir Retaining Pins

PIN PUNCH RESERVOIRBODYROLL PINS

Fig. 41 Loosening Reservoir

PRY TOOL RESERVOIRGROMMETMASTER CYLINDERBODY

Fig. 42 Reservoir Removal

RESERVOIRGROMMETS

5 - 2 2 BRAKES XJ



23/38

(4) Fill and bleed master cylinder on bench before

installat ion in vehicle.

DISC BRAKE CALIPER

DISASSEMBLY

(1) Remove brake shoes from caliper.

(2) Drain brake fluid out of caliper.

(3) Pad interior of caliper with minimum, 2.54 cm

(1 in.) thickness of shop tow els or r a gs (Fig. 45). Tow-

el s a r e n eed ed t o pr ot ect ca l iper pi st on d ur in g

removal.

(4) Rem ove ca l ip er p ist on w it h short bursts oflow pressure compressed air . Direct air through fluid

inlet port and ease piston out of bore (Fig. 46).

CAUTION: Do not blow the piston out of the borewith sustained air pressure. This could result in a

cracked piston. Use only enough air pressure toease the piston out.

WARNING: NEVER ATTEMPT TO CATCH THE PIS-TON AS IT LEAVES THE BORE. THIS MAY RESULT

IN PERSONAL INJURY.

(5) Remove caliper piston dust boot w ith suitable

tool (Fig. 47) and discard boot.

(6) Remove caliper piston seal w ith wood or plast ic

tool (Fig. 48) an d discard seal. D o not use m etal tools

a s t h e y w il l scr a t ch p ist o n bo r e .(7) Rem ove ca l ip er m ou n t in g bolt bu sh in g s a n d

boots (F

Documents

EXJ_599 jeep xj service manual