ck30 WM 09 Hydraulicdemss.co.kr/dossfile/manualn/WMFILE/CK25/CK30_WM_09... · 2006. 7. 26. · CHAPTER 9 CK25(H)/30(H) 9-4 D704-WOO Dec. 2004 1.2 HYDRAULIC CIRCUIT DIAGRAM OF 3-POINT

CHAPTER 9

HYDRAULIC SYSTEM

HYDRAULIC SYSTEM

9-3D704-WOO Dec. 2004

1.1 HYDRAULIC CIRCUIT DIAGRAM

1. STRUCTURE

704W901A

CHAPTER 9 CK25(H)/30(H)

9-4 D704-WOO Dec. 2004

1.2 HYDRAULIC CIRCUIT DIAGRAM OF 3-POINT HYDRAULIC SYSTEM

704W905A

(1) Oil Tank (Transmission Case)

(2) Oil Filter

(3) Hydraulic Pump

(4) Relief Valve (Optional)

A. HYDRAULIC OIL FLOW1. If the engine (4) is started and the hydraulic pump

(3) is rotated, hydraulic pump intakes oil from trans-mission case (1) through suction pipe. Hydraulicpump is supplied with oil and oil sludge is removedby oil filter.

2. Oil passes through filter by hydraulic pump to hy-draulic cylinder. If tractor installed with a front loader,oil preasure is extracted into front loader from hy-draulic block, re-flown in hydraulic block, and thenconnected with hydraulic circuit.

3. Oil enteres into position control valve through thehydraulic pipe.

(5) Aux. Control Valve

(6) Control Valve (MLS)

(7) Hydraulic Cylinder

(8) Hydraulic Cylinder Block

4. The position control valve selects oil flow and oilenters the hydraulic cylinder or exhausts into oil tank(transmission case) to operate 3-point hydraulicsystem.

* Hydraulic system contains a relief valve to limit themax. pressure of the hydraulic circuit.

* To use hydraulic working machine, operate work-ing machine clinder using the double acting valvewhen extracting hydraulic pressure.

HYDRAULIC SYSTEM

9-5D704-WOO Dec. 2004

(1) Inlet plug (PF 3/8") (3) Spool

(2) Outlet plug (PF 3/8") (4) Hydraulic Block body

704W906A

When implement is not attached

(1) From Implement (3) Spool

(2) To Implement (4) Hydraulic Block body

704W907A

When implement is attached[When using front loader or other implements]1. Remove the plugs from the outlet (2) and inlet (1) of

the hydraulic block (4).2. Install the adaptors to the outlet and inlet.3. Connect the hydraulic hose to the outlet adaptor

and to the implement control valve inlet.4. Connect the other hydraulic hose to the inlet adap-

tor and to the implement control valve outlet.5. Turn the slit on the spool (3) end to arrow side fully

as shown in the figure.

B. HYDRAULIC POWER TAKE-OFF

(IF EQUIPPED)1. HYDRAULIC BLOK

This hydraulic block type outlet is provided to operatethe hydraulic cylinders on the attached implement, suchas a front loader or a front blade.


9-6 D704-WOO Dec. 2004

R HYD CYL

P

INOUT

10

11

9

8

1

7

2

4

3

6

5

To Hyd. Cylinder

IN

OUT

RTFrom pump

Relief Valve (Hydraulic block)

(1) Plug (PF 3/8") (7) Metal Seal

(2) Retainer (8) Plunger

(3) O-ring (9) O-ring

(4) Spring (10) Adjusting Screw

(5) Seat (11) Lock Nut

(6) Poppet

704W908A

• As shown in the figure, a guide is attached at thepoppet(6).Intake of the valve is enabled through the sliding ofpart of the guide. The clearance of seat(5) to cham-ber minimizes valve vibration due to the dampingeffect.

• If oil pressure does not exceed the specified pres-sure of the relief valve, the relief valve will not oper-ate and oil flows from the hydraulic pump to theinlet of the hydraulic cylinder.

• As the oil pressure of the circuit increases, that ofdamping chamber D.C. increases. If the pressureexceeds the specified valve and the spring tension,the valve will open to flow oil through port T to thetransmission case. If oil is discharged sufficientlyand if pressure is less than specified, the valve willbe closed.

Item

Relief valve setting

pressure

Engine speed

Oil temperature

Factory spec.

17.2 ~ 17.7 Mpa

175 ~ 180 kgf/cm²

2489 ~ 2560 psi

Max.

45 ~ 55°C

113 ~ 131°F

HYDRAULIC SYSTEM

9-7D704-WOO Dec. 2004

1.3 HYDRAULIC SCHEME.

The hydraulic system consists essentially of a fluidtank, hydraulic pump, oil filter, oil cooler (CK25H,CK30H), HST(CK25H, CK30H), Joy-stick valve, controlvalve, and lift links.

The rear axle and transmission case serve as a com-mon hydraulic fluid tank and supply fluid to the hydrau-lic pump (2) through the filter (1) and suction tube.

The hydraulic pump supplies fluid to the system con-trol valve through the high-pressure line.

The control valve, when operated, affects raise, neutral,or lowering action of the lift arms.

704W904A

(1) Oil Filter

(2) Gear Pump

(3) Power Steering Unit

(4) One Lever Joy-Stick Valve: Optional

(5) Auxiliary Valve (Detent Type): Optional

(6) Control Valve (MLS Valve)

(7) Hydraulic Cylinder

(8) Charge Pump (CK25H, CK30H)

(9) Oil Cooler (CK25H, CK30H)

(10) HST Filter (CK25H, CK30H)

(11) HST (CK25H, CK30H)

(12) Steering Cylinder

7

6

5

10

9

1

2

4

3

11

12

8


9-8 D704-WOO Dec. 2004

B. FUNCTION AND OPERATION1. FunctionIt filters any particle or contaminated substances.

2. Operation principleThe filtering system as of an inlet filter installed on theinlet gear pump is composed of filter bracket and ele-ment ass’y.

The filter used for CK series tractors is applicable toboth hydraulic lift and steering wheel direction controlcircuits.

The hydraulic oil flows into the IN port of the filterbracket. The transmission oil is delivered into the hy-draulic element ass’y (3) and delivered out through theoutlet port to the hydraulic pump. All foreign substancesare filtered by the element at this time.

3. To checkThe hydraulic filter shall be replaced every service termof 200 hours.

(1) Filter Bracket

(2) Hydraulic Filter

(3) Hydraulic Element Ass’y

704W903A

1.4 OIL FILTER

A. STRUCTURE OF OIL FILTERThe suction filter (1) is a canister-type filter and shouldbe replace after 200 hour of use.

There is a permanent magnet installed on the center ofthe element of the hydraulic filter on the inlet hydraulicpump and the filter mounted on the hydraulic lift is struc-tured with a vacuum sensor and a thermo sensor todistinguish obstructions.

(1) Hydraulic Filter

(2) Filter Bracket

704W902A

HYDRAULIC SYSTEM

9-9D704-WOO Dec. 2004

6

16

15

11

9 10

12 13

14

4 78

5

1

2

3

1.5 JOYSTICK VALVE

704W909A

(1) Handle

(2) Rubber, Bellow

(3) Body Ass’y

(4) Mechanical Joystick Lcb Ass’y

(5) Spool Positioner


(7) Body Ass’y

(8) Plug

(9) Valve, Relief

(10) Spool

(11) Spool

(12) Cable Remote Cap Ass’y

(13) Cable

(14) Pin

(15) Plug

(16) Plug


9-10 D704-WOO Dec. 2004

The double-spool remote valve also contains a spring-loaded detent mechanism to provide a float positionfor loader operation. In float position, fluid is free toflow between piston and rod sides or the loader liftcylinder allowing the lift arms to float over uneven terrain.

The double-spool remote control valve contains checkvalves located in the valve spool passages. The checkvalves function to hold the loader lift and bucket cylin-ders in a fixed position while the valve is being initiallyoperated to prevent dropping the load. In operation, thecheck valve is retained on its seat by spring force plusthe back side pressure of fluid contained in the loadercylinder. During initial spool movement, pump-pres-surized fluid fills the passage to the check valve, andthe remaining pump fluid flows to the sump throughthe open center passage. With continued spoolmovement, the open center passage closes.

Pump pressure increases on the force of the checkvalve, overcoming the backside pressure, and causesthe check valve to open. Pump fluid flow then flows tothe cylinder. This action prevents any backflow out ofthe cylinder and provides a smooth-lifting action of theloader.

704W910A

704W911A

The Joystick valve is mounted on the right side of frontcover.

(1) Joystick Valve

HYDRAULIC SYSTEM

9-11D704-WOO Dec. 2004

A. DUMP POSITION

(1) Lift Control Valve Spool

(2) Bucket Control Spool

(3) Control Lever

(4) Bucket Cylinder

(5) Lift Cylinder

When the control lever (3) is moved to the dumpingposition, the bucket control spool (2) is moved inward.Fluid flow from the hydraulic pump is directed to thepiston side of the bucket cylinder (4).

The fluid contained in the rod side of the bucket cylin-der flows out of the cylinder through passage “A2” exit-ing the valve at port “T” and flows to the transmissioncase.

704W912A


9-12 D704-WOO Dec. 2004

B. REGEN POSITION



(3) Control Lever

(4) Bucket Cylinder

(5) Lift Cylinder

When the control lever (3) is moved to REGEN position,the bucket control valve spool (2) is moved completelyinward. Fluid flow from the hydraulic pump is directedto the piston side of the cylinder (4).

704W913A

Fluid on the rod side flows out of the through passage“A2”, overcomes the check valve spring force, and flowsto passage “B2” where it is combined with the pumpfluid and is directed to the piston side of the cylinder,allowing faster bucket-tipping action without cavitation.

HYDRAULIC SYSTEM

9-13D704-WOO Dec. 2004

C. ROLL BACK POSITION



(3) Control Lever

(4) Bucket Cylinder

(5) Lift Cylinder

When the control lever (3) is moved to the roll backposition, the bucket control valve spool (2) is movedoutward. Fluid flow from the hydraulic pump and isdirected to the rod side of the cylinder (4).

Fluid flow from the piston side of the cylinder flowsthrough passage “B2” exiting the valve at port “T” andflows to the transmission case.

704W914A


9-14 D704-WOO Dec. 2004

D. RAISING POSITION



(3) Control Lever

(4) Bucket Cylinder

(5) Lift Cylinder

When the control lever (3) is moved to the raising posi-tion the lift control valve spool (1) is moved outward.Fluid flow from the hydraulic pump is directed to thepiston side of the lift cylinder (5). The fluid contained inthe rod side of the lift cylinder flows out of the cylinderpast port “T” to the transmission case allowing theimplement to raise.

Because the bucket control spool (2) is in the neutralposition, the fluid trapped in the bucket cylinder (4) isblocked by the spool, and the bucket cylinder is held ina fixed position.

704W915A

HYDRAULIC SYSTEM

9-15D704-WOO Dec. 2004

E. LOWERING POSITION



(3) Control Lever

(4) Bucket Cylinder

(5) Lift Cylinder

When the control lever (3) is moved to the loweringposition, the lift control valve spool (1) is moved inward.Fluid flow from the hydraulic pump is directed to therod side of the cylinder (5). The fluid contained in thepiston side of the lift cylinder flows out of the cylinderpast port “T” to the transmission case allowing theimplement to lower.

704W916A


9-16 D704-WOO Dec. 2004

F. FLOATING POSITION



(3) Control Lever

(4) Bucket Cylinder

(5) Lift Cylinder

When the lift control lever (3) is moved to the detentposition (float), the control valve spool is moved in-ward beyond the normal lowering position. In thisposition, passage “B1” and “A1” are connected, andfluid is free to move between the lift cylinder rod andpiston ends.

The loader lift arms then move up and down as theloader passage over uneven terrain. Pump fluid pres-sure is directed out through the “T” port to the trans-mission case.

704W917A

HYDRAULIC SYSTEM

9-17D704-WOO Dec. 2004

1.6 AUXILIARY CONTROL VALVE (IF EQUIPPED)

(1) Body (6) Cover

(2) Nut (7) Safety Valve

(3) Screw (8) Spool

(4) Cover (9) Articulation

(5) Screw

704W918A

A double acting detent type secondary control valve isused. When the secondary control valve operating le-ver is moved to the implement cylinder actuatingposition, the spool is moved and the oil from the pumpport flows through A to B, causing the implement cylin-der to operate.

The return oil from the implement cylinder flows out ofthe tank port through A to B and returns to the transmis-sion case.

This special non-return type ensures that oil under pres-sure is held where necessary. This guarantees thatimplements will be held at a steady height with nochance of lowering.

QUICK COUPLERSThe quick couplers are proven to be connectable evenwith either half or both halves of the connectionspressurized. To connect the male half to the body, slidethe sleeve to the rear on the body half, and insert themale half into the body half.

Move the sleeve (5) forward to set the steel balls (4) forlocking the male half (1) into the body half (2). Themale half (1) is locked in place by a ring of steel balls(4) which is held in a groove on the inserted male halfby the outer sleeve (5).

(1) Male Half (4) Steel Ball

(2) Body Half (Female Half) (5) Sleeve

(3) Poppet

704W919A


9-18 D704-WOO Dec. 2004

1.7 CONTROL (MLS) VALVE

704W920A

A. OPERATION OF MLS CONTROL VALVEThe Control Valve has three distinct functioning phases:

1. Neutral Phase

2. Delivery Phase

3. Discharge Phase

(A) Charge (C) Neutral Position 109 ± 0.15

(B) Discharge

HYDRAULIC SYSTEM

9-19D704-WOO Dec. 2004

704W921A

In this phase the control valve keeps the oil in the cylin-der under pressure, bearing the load while the oil com-ing from the pump flows freely into.

This control spool (1) is in the position to connect cham-ber (26) of the pilot valve (27) directly to the dischargethrough hole (16). Thus allowing the same valve to openhole (28) which discharges chamber (15) by means ofthe duct (29) of the regulator piston (2). Thus the oilcoming from the pump feeds chamber (22) and allowsthe regulator piston (2) to open the holes (17) and theoil flows to the tank.

(1) Control Spool

(2) Regulator Piston

(3) Check Valve

(4) Discharge Valve

(5) Safety Valve

(16) Discharge Through Hole

(17) Hole

(18) Annular Duct

(22) Pump Feeds Chamber

(23) Chamber

(26) Position to Connect Chamber

(27) Pilot Valve

(28) Hole

a. Neutral Phase

The oil contained in the cylinder chamber (23) remainsunder pressure by means of the check valve (3), by thedischarge valve (4) and by the safety valve (5) whichare connected to the cylinder by the annular duct (18)and thus sustains the load applied to the lifting arms.

The safety valve (5) protects the cylinder from the pos-sibility of eventual over- pressure due to the oscillationof the load during road transport.


9-20 D704-WOO Dec. 2004

During this phase the Control Valve supplies oil underpressure to the cylinder chamber (23) and this conse-quently lifts the arms.

The control spool (1) is in the position to connect cham-ber (26) of the pilot valve (27) with the oil coming fromthe pump through the annular duct (19) and the holes(20), (21) and (30); thus allowing the same valve toclose itself. The oil coming from the pump feeds at thesame pressure chamber (22) and chamber (15)(through duct (29) of the regulator piston (2) that closesthe discharge holes (17) due to the upward push of thereturn spring.

The oil under pressure flows to the cylinder throughthe annular duct (19); enters in hole (20) through thefixed throat (6) and the variable throat made by the con-trol spool (1) with the hole (21), opens the check valve(3), enters in the annular duct (18) and feeds chamber(23) of the cylinder.

704W922A

(1) Control Spool


(3) Check Valve

(17) Hole

(18) Annular Duct

(19) Annular Duct

(20) Hole

(21) Hole

(22) Chamber

(23) Chamber


(27) Pilot Valve

(29) Duct

b. Delivery Phase

The regulator piston (2) regulates the oil flow of thecylinder because chambers (15) and (22) are subjectto the difference in pressure created by the oil in thepassage through the fixed throat (6) and the variablethroat (31) which is opened or closed by the controlspool (1), in function of its movement caused by inter-nal levers of the rockshaft.

The excessive flow is deviated on the rising pressurefrom holes (17), thus regulating the maximum liftingspeed and allowing a slow starting and arrival of thelifting arms.

The maximum lifting pressure is controlled by a reliefvalve external to the rockshaft control valve or by usingthe one already existing in the auxiliary control valves.

HYDRAULIC SYSTEM

9-21D704-WOO Dec. 2004

During this phase the Control Valves supplies to thedischarge both the oil coming from the pump as wellas the oil coming from chamber (23) of the cylinder,with the consequential lowering of the lifting arms.

The control spool (1) is in the position to connect cham-ber (26) of the pilot valve (27) directly to the dischargethrough hole (16); thus allowing the same valve to openhole (28) that flows to the discharge through duct (29)chamber (15) of the regulator piston (2). The oil com-ing from the pump, as in the neutral phase, is able tomore the regulator piston towards chamber (15) thatopens the discharge holes “17” causing oil to flow tothe tank. At the same time the oil from the cylinder un-der pressure chamber (23) enters in the annular duct(18) passes through the holes (32), the lowering regu-lator (8) and hole (24) enters in the discharge valve (4)flowing to the tank from hole (25), causing the loweringof the arms.

704W923A

(1) Control Spool


(4) Discharge Valve

(5) Safety Valve

(8) Lowering Regulator

(15) Chamber

(16) Discharge Through Hole

(17) Discharge Hole

c. Discharge Phase

(18) Annular Duct

(23) Chamber

(24) Hole

(25) Hole


(27) Pilot Valve

(28) Hole

(32) Hole

In this phase the lowering speed of the arms can beregulated with the manual lever (RD); by screwing itthe lowering speed can be reduced.

For safety during road transport, against the accidentalmovement of the control lever of the rockshaft, screwthe lever (RD) to the end so as to close the valve (8)completely against its seat so as to close the duct be-tween chamber (23) of the cylinder and the dischargevalve (4).

When the safety mechanism is inserted the cylinder isalways protected by accidental over-pressure by thesafety valve (5).


9-22 D704-WOO Dec. 2004

(if Draft Equipped)

704W924A

HYDRAULIC SYSTEM

9-23D704-WOO Dec. 2004

B

(if Draft Equipped)

(1) Lever

(2) Needle Bearing

(3) Washer

(4) Packing

(5) Pin

(6) Roller 3

(7) Set Screw

(8) Oil Seal

(9) Snap Ring

(10) Link 4

(B) If Draft Equipped

704W925A

(11) Shaft

(12) Spring Pin

(13) Cam

(14) Snap Ring

(15) Link 1

(16) Link 2

(17) Roller 4

(18) Plain Washer

(19) Pin

(20) Roller 1

(21) Roller 2

(22) Snap Ring

(23) Link 3

(24) Arm

(25) Set Screw

(26) Cam 1

(27) Pin

(28) Nut

(29) Link

(30) Snap Ring

(31) Arm

(32) Nut

(33) Bolt

(34) Pin

(35) Pin

(36) Spring

(37) Link

(38) Pin

(39) Snap Ring

(40) Plain Washer


9-24 D704-WOO Dec. 2004

704W926A

2.1 PRINCIPLE OF CONTROL

A. Position Control

By moving the control lever (2) toward the backstop onthe lower sector part, the roller 4 (11) sliding on thelever (7) of drawbar pull cam (12) will be moved awaycompletely.

In that manner, the drawbar pull levers will not in anyway interfere with the operation of the position control.

The raising movement of the arms is obtained by mov-ing the position control lever (1) upward, and the lever-age system will act in the following way.

The arm (4) being an integral part of shaft (3) turns in aclockwise direction and causes the roller 1 (5) to slideon the positioning cam 1 (6), in turn causing the clock-wise rotation of lever (7); the lever will transmit a counter-clockwise rotation, by means of friction shock absorber(8), to the transmission arm (9) that will bring the dis-tributor shaft (21) into delivery position (C), thus caus-ing the arms to be lifted.

(1) Position Control Lever

(2) Draft Control Lever

(3) Shaft

(4) Arm

(5) Roller 1

(6) Cam 1

(7) Lever

(8) Friction Shock Absorber

(9) Arm

(10) Pin

During the lifting movement of the arms; crank (13)with pin (10) will rotate in a counter-clockwise direction,and via link 3 (14) will cause the positioning cam 1 (6)to rotate clockwise. When roller 1 (5) meets the in-clined plane of cam 1 (6) this will allow a counter-clock-wise rotation of the lever (7) causing the transmissionarm (9) to rotate in a clockwise direction, via the frictionshock absorber (8). Arm (9) is pushed by the spring ofthe distributor shaft (21) which will pass into the neu-tral position “N” there by stopping the movement of thelifting arms.

During the lowering phase of the arms, all leveragemovements as described above will occur in the oppo-site sense.

Both during lifting or lowering movements, the positionof the arms will conform to a specific position of thecontrol lever (1) on the sector.

(11) Roller 4

(12) Cam

(13) Hydrauic Arm

(14) Link 3

(21) Shaft

2. OPERATION

HYDRAULIC SYSTEM

9-25D704-WOO Dec. 2004

704W927A

B. Draft Control (If Equipped)

By positioning the control lever (1) for position controlagainst the lower backstop on the sector, the armreaches the utmost position of counter-clockwiserotation.

In said position, the roller 1 (5) is totally lowered fromthe inclined plane of the positioning cam 1 (6) allowingthe counter-clockwise rotation of the lever (7) as wellas the clockwise rotation of the transmission arm (9).It is pushed by the spring of shaft (21) which in turn willposition itself for the discharge of the drawbar pullcontrol.

By positioning the drawbar pull control lever (2) againstthe back stop in the upper part of the sector, the draw-bar pull control shaft (16), will reach its extreme of ten-sion rod (17) will move roller 4 (11) the latter acting ondrawbar pull cam (12).



(3) Shaft

(7) Lever

(8) Friction Shock Absorber

(9) Arm

(11) Roller 4

(12) Cam

(15) Link 1

(16) Pitman Arm

(17) Link 2

(18) Tie-rod

This causes the lever (7) to rotate clockwise of the trans-mission arm (9) thus setting the distributor shaft (21)into delivery position “C” and consequently lifting thearms. The arms will come to a stop only when the thepiston comes into contact with the pin of the limit stop(22).

The axis limit stop, by means of the tension rod (23),causes the arm (9) to rotate clockwise, thereby com-pressing the spring of the friction shock absorber (8)and thus releasing the shaft (21) which now can moveto the neutral position “N” where it is pushed outwardby its spring.

Moving the drawbar pull control lever (2) downward,the leverage system will function in the followingmanner.

Being an integral part of drawbar pull shaft (16), thecrank (15) rotates counter-clockwise and by means oftension rod (17), causes the roller 4 (11) to slide on thelever (7).

(19) Crank

(20) Top Link Holder

(21) Shaft

(22) Pin

(23) Link


9-26 D704-WOO Dec. 2004

C. Combined Operation of Positioning andDrawbar Pull (Fig. 704W927A,704W928A)

To utilize the lifting device in this condition, it is neces-sary to observe the following instructions; Move thepositioning control lever (1) upward (in relation to thelower backstop on the sector) until the maximum work-ing depth has been attained. Determine the desiredminimum working depth by operating the drawbar pullcontrol lever and raising it from zero position so thatroller 4 (11,) by acting on drawbar pull cam (12), will getdistributor shaft (21) into lifting position “C”. The cam(12) should also cause a further upward movement ofthe lifting arms.

Due to the position previously established by the posi-tion control lever (1), the lever (7), arm (4), and positioncam 1 (6) will prevent the distributor shaft (21) fromentering the lowering position “S” and therefore thearms cannot sink. The force of traction acting on thehitchpoint (20) will tend to diminish by stressing ten-sion rod (18) in the direction of arrow “N”.

Such condition will not keep the lifting device from op-erating under drawbar pull control, providing the workis carried on in reasonably consistent soil. The tractionforce acting on hitch point (20) will then tend to increaseexerting stress on tension rod (18) in the direction ofarrow “RP”.

Consequently, the combined operation of the positioncontrol and drawbar pull control will limit variations inheight toward the ground as they intervene during useof the controlled drawbar pull, at the same time ensur-ing the maximum possible desirable depth.

When roller 4 (11) meets the inclined plane of the draw-bar pull cam (12), it permits the counterclockwise rota-tion of lever (7) which by means of shock absorbers (8)will rotate transmission arm (9) in a clockwise mannerthus releasing the distributor shaft (21) to move intoneutral position “N”.

In discharge position “S”, the lever (2) will continue itsdownward movement and cause the arms to lower. Infact, during the initial part of the downward movementof the drawbar pull control lever (2), no lowering of thecam arms can be noticed.

The force of traction at the hitch point (20) acts on ten-sion rod (18) in the direction indicated by arrow “RP”causing the flywheel (19) to rotate clockwise togetherwith the drawbar pull cam (12) which is fastened to thesame stud.

When the inclined plane of the drawbar pull cam (12)meets roller 4 (11), clockwise rotation of the lever (7) isachieved. By means of the shock absorber (8), it causesthe transmission arm (9) to rotate counterclockwisethereby bringing the distributor shaft (21) into neutralposition “N” and stopping all movement of the arms.

As the force of traction is increased, the drawbar pullcam (12) will further move roller 4 (11) incrementingthe movement as described above.

The distributor shaft (21) will move from the neutralosition “N” toward the delivery position “C” causing thearms to be lifted.

When the force of traction diminishes, it will cause aninverted action of the leverage system as previouslyexplained.

HYDRAULIC SYSTEM

9-27D704-WOO Dec. 2004

704W928A

3.2 OPERATIONIf shock is applied to the implement, it will be absorbedby the cover (3), spring (4), and top link. The top link isconnected to the linkage by plate (7) and tie rod (9).This will elevate the implement.

The oil flow passage will be changed by the linkage inthe MLS valve.

3.1 STRUCTURE (If Draft Equipped)

(1) Top Link Holder

(2) Flange

(3) Cover

(4) Spring

(5) Nut

(6) Hex. Bolt

(7) Plate

(8) Crank

(9) Tie Rod

(10) MLS (Control) Valve

3. TOP LINK BRACKET DEVICE


9-28 D704-WOO Dec. 2004

Provable Causes• Insufficient oil level in the tank.

• Pump inlet filter clogged.

• Infiltration of air into the pump inlet pipe.

• Adjusting piston or pilot valve stuck.

• Sensibility adjusted badly

• Faulty adjustment of the control lever

• Hydraulic block switched on.

• Outlet valve spring damaged.

• Piston Blocked

• Safety and over-pressure valves out of calibration

• Poor pump efficiency.

• Poor Control Valve efficiency

• Deterioration of the Control Valve seal rings.

• Piston gasket worn.

• Oil leakage from cylinder.

• Oil leakage from one of the following Control Valvesvalves: non-return valve outlet valve safety valve,protecting the cylinder.

• Faulty adjustment of the max. Upper position of lift arms.

Symptom

The rockshaft liftsjerkily.

Rockshaft does notoperate.

The rockshaft doesnot descend over itsentire travel.

The rockshaft doesnot descend.

Lifting capacitydoes not match thatprescribed.

The rockshaftsupports loads withdifficulty; there is arhythmic oscillationwhen the motor ison; the load de-scends when themotor is off.

When the arms are inthe upper position,the safety valve(relief valve) placedon the body of therockshaft startsoperating

4. TROUBLESHOOTING

4.1 POWER LIFT ASSEMBLY

SolutionTop up the level.

Clean or replace the filter.

Check the inlet pipe andany coupling and gasket.

Remove the control valveand unblock the pilot valveand adjusting piston(page 9-45 and 9-46)

Adjust sensitivity of ControlValve (page 9-56)Adjust control positionlever (page 9-55)

Unscrew the manual lever(RD, page 9-56)Change the spring(page 9-46)Check piston and cylinder

Control calibration of the 2valves.Replace the pump.

Overhaul the Control Valve.

Remove the Control Valveand replace the externalseal rings.

Replace the gasket.

Overhaul the cylinder.

Remove the Control Valveand overhaul the followingvalves: page 9-43,page 9-45 to 9-52In case of leakage over-haul the Control Valve.

Adjust the control lever,limiting the max. upperposition travel. (page 9-56).

HYDRAULIC SYSTEM

9-29D704-WOO Dec. 2004

Symptom

External leakagecontrol kit or oppositeside.

Excessive internalleakage on A and Bports.

Dropping load duringtransition while raising.

Inability to buildpressure on A and Bports.

4.2 JOYSTICK VALVE

Provable Causes• Worn spool seal due to mechanical actuation or

high back pressure.

• Increase clearance between spools and body dueto high wear

• High leakage of the load check valve.

• Main pressure relief valve blocked open.

• Port relief valve open.

• Low pump pressure and flow.

Solution

Locate the leakage andreplace the seal.Check back pressure level.

Replace the directioncontrol valve and check theoil contamination level.

Remove the load checkvalve and clean the seat.

Remove and clean orreplace the main relief valve.

Remove and clean orreplace the port relief valve.

Check the pump and circuit.


9-30 D704-WOO Dec. 2004

B. DIMENSIONAL FEATURES

Reference Dimension

90 mm (3.54 in)

87.5 mm (3.45 in)

556.6 cm³ (34 in3)

70°

78°

70°

178.4 kgf/cm² (17.5 MPa)

200 kgf/cm² (19.6 MPa)

Item

Piston diameter

Working stroke

Piston displacement

Angular excursion of lifting arms in controlled position

Angular excursion of lifting arms in internal mechani-cal limit stop

Excursion of control lever

The position relifef valve is external of the rockshaftcalibration of relifef valve

Calibration of cylinder safety valve

CONTROL (MLS) VALVEA. TECHNICAL FEATURES

• Functioning at controlled position

• Three point linkage fixed

• Possibility to regulate the lowering speed of implement

• Manual hydraulic stop against accidental lowering of implement during road transport

• Limit stop of lifting arms in position of maximum height determined by position lever

• Sector control with lever

• Functions with oil of transmission

• Oil filter not built-in

• Required degree of filtering : 20 ∼ 25 µm

• Oil temperature : 80°C

Reference Dimension

Gear

48.1 /min (12.7 gpm)

1/1

150 (mesh)

1,078 cm² (167.1 in²)

62 ± 6 (max.)

44 ± 4 (min.)

175 kgf/cm² (17.2 MPa)

4way 5Position

45 /min (11.9 MPa)

Double acting Control

Valve 2way 3Position

Item

Hydraulic pump

Main hydraulic lift

HST hydraulic filter

(CK25H/30H)

Hydraulic Block (optional)

Joy-stick valve

Auxiliary valve (optional)

Type

Pump capacity

Pump gear ratio

Micron rating

Area

Micron rating

Relief valve setting pressure

Type

Nominal flow rating

Type

5. SPECIFICATION

HYDRAULIC SYSTEM

9-31D704-WOO Dec. 2004

6.1 HYDRAULIC PUMP

A. BONNET1. Open the bonnet (1).

2. Remove the side cover (RH) (2).

3. Disconnect the battery terminal (-) (3).

(For assembly)When connect the battery terminal (-), apply a littlegrease to it.

704W929A

(1) Bonnet (3) Battery Terminal (-)

(2) Side Cover

B. HYDRAULIC PUMP1. Remove the hoses assembly (P) (1), pipe band (2)

and hose assembly (T) (3).

2. Remove the joint bolt (4), bolts, and O-rings.

3. Remove the bolts (5), pipe bands (6), suction pipe3 (7) and O-ring.

4. Remove the bolts, Hydaulic pipe (8) and O-ring.

5. Remove the bolts and pump (9).

(1) Steering Hose Assembly (P)

(2) Pipe Band

(3) Steering Hose Assembly (T)

(4) Joint Bolt

(5) Bolt

(6) Pipe Bands

(7) Suction Pipe 3

(8) Hydaulic Pipe (J1)

(9) Pump

(10) Steering Pipe 1

704W930A

(When reassembling)

Item

Joint bolt

Tightening torque

44.1 N·m

4.5 kgf·m

32.5 lb·ft

6. DISASSEMBLING AND MAINTENANCE


9-32 D704-WOO Dec. 2004

704W932A

6.2 JOY-STICK VALVEA. DISASSEMBLE1. Remove the hydraulic pipe (J1) (4), joint bolt (5), O-

ring (6), return pipe (J) (7), joint bolt (8), O-ring (9)and hydraulic pipe(J2) (10).

2. Remove the bolts (1), Spring washers (2), and plainwashers (3).

3. Remove the bolts (11), Spring washers (12) andthe valve (13).

(When reassembling)

Item

Joint bolt

Tightening torque

44.1 N·m

4.5 kgf·m

32.5 lb·ft

704W931A

(1) Bolt

(2) Spring Washer

(3) Plain Washer

(4) Hydraulic Pipe (J1)

(5) Joint Bolt

(6) O-ring

(7) Return Pipe(J)

(8) Joint Bolt

(9) O-ring


(11) Valve Stopper Bolt

(12) Spring Washer

(13) Joystick Valve Assembly

HYDRAULIC SYSTEM

9-33D704-WOO Dec. 2004

Inspection:1. Inspect the spools and the spool bores for pitting,

scratching, or excess wear. If they are founddefective, replace the Joy-stick valve assembly.

2. Check that the spool moves freely in the spool bore.

3. Inspect the load check valve poppets for pitting orscratches.

4. Inspect all springs for distortion. Replace thosefound to be defective

5. Replace all O-rings and seals during reassemblyand lightly lubricate with petroleum jelly.

• The float spool (10) and spool (11) are not inter-changeable and will only work in their respectivebores.Ensure that the spools are inserted into the properbores during reassembly.

IMPORTANT

B. DISASSEMBLY THE JOY-STICK VALVE

5. Disassemble the spool (11) in the same manneras the float spool using steps 1 through 4.

6. Remove the load check plugs (8) with the O-rings,springs, and load check poppets from the checkvalve ports.

1. Loosen the nuts from cable (13) and remove thescrews (12), rod pins (14) and cables (13).

2. Remove End cap screws, then End cap (5) from thefloat spool (10).

3. Remove end cap screws and End cap (6) from thespool (11).

4. Gently slide each float spool (21, 22) with the spoolcontrol kit, Ring and O-ring out of the valve body.

6

16

15

11

9 10

12 13

14

4 78

5

1

2

3

704W933A

(1) Handle

(2) Rubber, Bellow

(3) Body Ass’y

(4) Mechanical Joystick Lcb Ass’y



(7) Body Ass’y

(8) Plug

(9) Valve, Relief

(10) Spool

(11) Spool

(12) Cable Remote Cap Ass’y

(13) Cable

(14) Pin

(15) Plug

(16) Plug


9-34 D704-WOO Dec. 2004

2. Install the load check poppets with O-rings, springsand check plugs (15).

Item

Plug

Nut

Tightening torque

42 N·m

4.3 kgf·m

31 lb·ft

24 N·m

2.5 kgf·m

18.0 lb·ft

c. Joy-stick Valve Assembly1. Install the relief valve (9).

Item

End cap mountingwrench bolt

Spool control kit

Tightening torque

6.6 N·m

0.7 kgf·m

4.9 lb·ft

9.8 N·m

1.0 kgf·m

7.2 lb·ft

5. Assemble the float spool (10) in the same mannerusing steps 3 through 4.

704W934A

(1) Plug (3) Nut

(2) Screw

3. Install O-ring into the grooves in the valve body andcarefully slide the spool (11) into its bore.

4. Install the end cap (5) and secure the assemblywith cap screws.

Item

Check plugs

Tightening torque

42 N·m

4.3 kgf·m

31 lb·ft

704W935A

(1) Wrench Bolt (2) Spool Control Kit

704W936A

(1) Wrench Bolt (2) Spool Control Kit

HYDRAULIC SYSTEM

9-35D704-WOO Dec. 2004

704W937A

6. Install the cables (13), rod pins (14) and screwsinto the assembly and tighten its locknut.

(1) Wrench Bolt

Item

Wrench bolt

Tightening torque

6.6 N·m

0.7 kgf·m

4.9 lb·ft


9-36 D704-WOO Dec. 2004

A. ROPS1. Remove the lock pin, linch pin, and rops from the

rops support.

2. Remove the bolts and ROPS supports (LH, RH).

B. SEAT, LEVERS1. Raise the frame assembly with nylon rope and re-

move the mounting bolts in the seat floor.

2. Remove the seat assembly.

3. Remove the grips of Hi-Lo shift lever, PTO lever andothers.

4. Remove the bolts and the lever guides (LH, RH).

5. Remove the bolt, lever bracket and lever guideplates.

6. Disconnect the position lever, draft lever, and exter-nal hydraulic valve levers.

C. FENDER1. Disconnect the brake lamp wire connector and then

remove from fender.

2. Disconnect the wiring connectors for the work lamp,back lamp.

3. Raise the frame assy. with nylon rope. Remove themounting bolts in the seat floor and front cover.

4. Remove the fender.

(1) ROPS

(2) ROPS Support

704W938A

704W940A

704W939A

(1) Seat (3) PTO Lever

(2) Hi-Lo Shift Lever

(1) Fender

6.3 SEPARATE THE HYDRAULICCYLINDER

HYDRAULIC SYSTEM

9-37D704-WOO Dec. 2004

F. FRONT COVER, STEP1. Remove the pin and then remove the main shift lever.

2. Remove the grip of front wheel drive lever.

3. Remove the snap ring and pin in the down speedcontrol rod and then remove the down speed con-trol rod.

4. Disconnect the differential lock pedal rod.

5. Remove the joystick lever and front cover mountingbolts.

6. Remove the front cover and step mounting bolts.

7. Remove the step (LH, RH) and support bracketmounting bolts.

G. LINKS1. Remove the clip pin, top link pin and the top link.

2. Remove the clip pin, lift rod pin and lifts.

3. Remove the mounting bolts and top link holder.

Sect. Spec. Tightening Torque

Top link holder and

mounting bolt

M12

M10

77.5 ~ 90.2 N·m

7.9 ~ 9.2 kgf·m

57.2 ~ 66.5 lbf·ft

48.1 ~ 55.8 N·m

4.9 ~ 5.7 kgf·m

35.5 ~ 41.2 lbf·ft704W942A

(1) Top Link (3) Top Link Holder

(2) Lift Rod

704W941A


9-38 D704-WOO Dec. 2004

(1) Filter Connector

(2) Hydraulic Pipe (A)

(3) Hydraulic Pipe (B)

(4) Hydraulic Pipe (C)

(5) Hydraulic Pipe (D)

(6) Socket Support

(7) Bolt

(8) Coupler Socket Assy

(9) Joint Bolt 2

(10) O-Ring

(11) Joint Bolt

(12) Detent Floating Valve Assy

704W943A

H. PIPE, AUX. CONTROL VALVE (IF ATTACHED)

1. Remove the joint bolt (9, 11), hydraulic pipe (2, 3, 4,5), socket support (6) and quick coupler.

2. Remove the nut (17) from aux. control valve and thenremove the aux. control valve from the hydraulic cyl-inder body.

(13) Double Valve Assy

(14) O-Ring

(15) O-Ring

(16) Cover

(17) Nut

(When reassembling)• Make sure the O-ring is not damage.

Item

Joint bolts

Tightening torque

29.4 ~ 34.3 N·m

3.0 ~ 3.5 kgf·m

21.7 ~ 25.3 lb·ft

HYDRAULIC SYSTEM

9-39D704-WOO Dec. 2004

1414

13

12

1. Remove the joint bolt (12) and O-rings (14).

2. Remove the hydraulic cylinder assembly mount-ing bolts (8,9,10,11), spring washers (5) and nuts(6).

3. Separate the hydraulic cylinder assembly (1) fromthe transmission case.

(1) Hydraulic Cylinder Assembly

(2) Packing

(3) Straight Pin

(4) Stud

(5) Spring Washer

(6) Nut

(7) Stud

(8) Bolt

(9) Bolt

(10) Bolt

704W944A

(11) Bolt

(12) Joint Bolt


(14) O-Ring

Item

Hydraulic cylinder

mounting bolt and nut

Joint bolt

Tightening torque

48.1 ~ 55.8 N·m

4.9 ~ 5.7 kgf·m

35.5 ~ 41.2 lb·ft

29.4 ~ 34.3 N·m

3.0 ~ 3.5 kgf·m

21.7 ~ 25.3 lb·ft

(When reassembling)• Be sure to replace the gasket with a new one.

I. HYDRAULIC CYLINDER


9-40 D704-WOO Dec. 2004

704W945A

J. DISASSEMBLING THE HYDRAULIC CYLINDER a. Hydraulic Control Lever

(A) Only Position Control

(1) Set Screw

(2) Bolt

(3) Hydraulic Lever Support

(4) Pitmans Arm

(5) Clutch

(6) O-Ring

(7) O-Ring

(8) Screw

(9) Spring

(10) Clutch Hub 1

(B) If Draft Control Equipped

(11) O-Ring

(12) Snap Ring

(13) Flange

(14) Clutch Hub 2

(15) Bolt

(16) Shaft

(17) Control Lever

(18) Bolt

(19) Stopper

(20) Shaft

1. Remove the screw(1) and bolts(2) for mount thehydraulic lever support.

2. Remove the relevant parts as shown in the figure.

HYDRAULIC SYSTEM

9-41D704-WOO Dec. 2004

(1) Snap Ring (13) Pin

(2) Lift Arm (Left) (14) Hydraulic Rod

(3) Lift Arm (Right) (15) Piston

(4) Washer (16) Back up Ring

(5) Seal (17) O-Ring

(6) Bush (18) Cylinder

(7) Bush (19) O-Ring

(8) Bush (20) Seal Washer

(9) Hydraulic Arm (21) Bolt

(10) Screw (22) Seal Washer

(11) Hydraulic Arm Shaft (23) Bolt

(12) Spring Pin

(A) Hold (B) Hark

704W946A

(When Reassembling)• Take care of backup ring (9) and o-ring (8) insert

into piston (7).

• Apply the cylinder with transmission oil and insertthe piston.

• Apply the bottom of the piston that contact with thehydraulic rod with grease.

• Alive with holes of shaft (1) and hydraulic arm (2)

• Apply grease to the right and left bushings of hy-draulic cylinder.

• Properly align the alignment of the hydraulic armshaft and hydraulic arm (9), and the alignmentmarks (B) of the hydraulic arm shaft (11) and liftarm (2).

b. Lift Arm, Hydraulic Cylinder Arm, HydraulicArm Shaft

1. Loosen the cylinder mounting bolts (13,16) andhydraulic arm mounting screw (10).

2. Remove the snap ring (1) and detach the hydrau-lic arm shaft (11) and lift arms, tapping on it us-ing a urethane hammer.

3. Remove the hydraulic cylinder (18), piston (15),hydraulic rod (10) and hydraulic arm.


9-42 D704-WOO Dec. 2004

704W947A

a) Disassembly1. Before disassembling the top link holder assembly,

disassemble the socket support and coupler socketassembly.

2. Disassemble bolt (12), roller (13), and plate (11).

3. Disassemble nut (19).

4. Remove snap ring (10) and then disassemble pin(9).

5. Disassemble top link bracket (1).

6. Pull out bolt (7), (8), and then disassemble flange(2).

7. Disassemble cover (3), spring (4), roller (5), andbolt (6) in the assembly.

(1) Top Link Holder (11) Plate

(2) Flange (12) Bolt

(3) Cover (13) Roller

(4) Spring (14) Nut

(5) Roller (15) Tie Rod

(6) Bolt (16) Snap Ring

(7) Bolt (17) Crank

(8) Bolt (18) Pin

(9) Pin (19) Nut

(10) Snap Ring

• Don’t change the assembled positionof plate when disassembling flange(2).

• Make sure top link holder (1) does notfall to ground when disassembling pin(9).

• When assembling bolt (7), check draftfor operation and then repeat assem-bly several times.

CAUTION

b) Assembly1. Apply bolt (6), and spring (4) with grease sufficiently

when assembling.

c. Top Link (If equipped)

HYDRAULIC SYSTEM

9-43D704-WOO Dec. 2004

d. Control valve (MLS Valve)

1. Remove the bolts (1).

2. Draw out the control valve (2) from the power liftbody (3).

(When reassembling)

NOTE:• Installation is carried out in reverse order of removal.

1. Install new O-rings on body of control (MLS) valve if.

2. Orient control valve so that the mounting holes lineup with the appropriate holes in the housing withthe shaft and that time the control shaft locate to-wards the bottom of the housing (See removal storystep)

3. Lubricate control valve bore in housing with hydrau-lic oil and being careful not to damage O-rings, slideshaft control valve into housing. Secure with twobolts.

4. Install hydraulic control rod and U-joint securing withpin and snap ring.

Item

Control valve mountingbolt

Tightening torque

23.6 ~ 27.4 N·m

2.4 ~ 2.8 kgf·m

17.4 ~ 20.2 lb·ft

704W948A

(1) Bolt

(2) Control Valve Assembly (MLS Valve)

(3) Power Lift Body (Hydraulic Cylinder Block)


9-44 D704-WOO Dec. 2004

K. CONTROL (MLS) VALVE DISASSEMBLY,ASSEMBLY AND INSPECTION

1. Remove the control valve from the housing(Hydraulic cylinder).

2. Remove the O-rings from outside of the body.

704W949A

(1) O-Ring

3. Remove the rubber boot (3) from speed control shaft

4. Remove three socket head cap screws (2) secur-ing to body of rockshaft control valve.

704W950A

(1) Control Valve Body

(2) Socket Head Cap Screws

(3) Rubber Boot

(4) Speed Control Shaft

(5) Head Cap

5. Remove the spool valve (1) from head end of body(3).

6. Remove the speed control valve (2) from head endof the body.

704W951A

(1) Spool Valve (3) Body

(2) Speed Control Valve

HYDRAULIC SYSTEM

9-45D704-WOO Dec. 2004

NOTE:• Valves are composed of matched components

(spools, springs, body, etc.). If any component showswear, the entire valve must be replaced.

NOTE:• Orientation of balancing passage in one end of the

spool is very important. This balancing passagemust be assembled facing towards the cap of spoolvalve.

7. Inspect the components for wear. Replace asrequired.

8. Screw a bolt into the valve located under the speedcontrol valve and remove the valve.

9. Remove the spring and ball under valve.

10.Inspect components for wear paying special atten-tion to valve and seats. Replace as required.

704W952A

704W953A

(1) Pilot Spool (6) Pin

(2) Spring (7) Valve

(3) Valve (8) Seat Valve

(4) Plug (9) Spring

(5) Lever Ass’y (10) Valve

(1) Valve (4) O-Ring

(2) Spring (5) Body

(3) Pilot Spool

• The e nd plate is under tension from valve springs.DO NOT remove the socket head cap screws se-curing the end plate to the body without retainingthe head as indicated in the story.DO NOT disturb the set screw with the lock nut!Removing this screw will change internal reliefpressures!

IMPORTANT


9-46 D704-WOO Dec. 2004

16.Compress the spring until it is free of spring pocket.Remove the spring and valve spool from end plate.

14.Remove the end plate, spring and valve spool as aunit.

15.Note the location of spacers, plug, piston and springfollowers.

704W955A

704W956A

(1) Spring (5) Spring Followers

(2) End Plate (6) Valve Seat

(3) Piston (7) Valve Spool

(4) Spacers

(1) End Plate (3) Spring

(2) Spring Pocket (4) Valve Spool

11. Remove the center socket head cap screw. Secureone of the socket head cap screw that were used tosecure head to body (longer than plate screw) inthe center hole.

12.Place the valve, head end down, on a level surfaceto reduce the chance of loosing internalcomponents.

13.Back off all three screws evenly until the two out-side screws disengage from threads in the body. Atthis point the spring tension will be relieved to asafe level. Unscrew the center screw and remove.

704W954A

(1) End Plate


(3) Set Screw Lock Nut (4) Body

HYDRAULIC SYSTEM

9-47D704-WOO Dec. 2004

19.Use magnet to remove the ball from body. Also re-move the ball seat if it did not come out with thespring.

20.Remove the valve seat from the body.

704W958A

704W959A

(1) O-Ring (2) Valve Seat

17.Remove the spacers.

18.Remove the spring follower and spring from body.

704W957A

(1) Spring Follower (3) Spring

(2) Spacers


9-48 D704-WOO Dec. 2004

22.Remove the plug and the piston spring from thebody.

23.Inspect the O-ring on the plug. Replace i t i fdamaged.

704W961A

704W962A

(1) Plug (3) Spring

(2) O-Ring

(1) Spring

21.Remove the pilot valve from body.

704W960A

(1) Pilot Valve

HYDRAULIC SYSTEM

9-49D704-WOO Dec. 2004

25.Remove the orifice screw from the side of the body.

26.Make sure the hole in the orifice screw is notplugged or damaged.

704W964A

(1) Orifice Screw

24.Remove the spool from body.

704W963A

(1) Spool

• DO NOT attempt to remove balls used to blackdrill passages in body.

IMPORTANT

27.Clean body and components in suitable solvent.Carefully blow out all passages in the body withcompressed air.

28.Inspect the body and all components for wear ofdamage. Pay special attention to be sure that allports and small passages are clean and open.Replace as required.

NOTE:• Individual components of speed control valve are

not serviceable. If the body and/or components areworn or damaged the entire speed control valve mustbe replaced as a unit.

Assembly:

NOTE:• Assembly is carr ied out in reverse order of

disassembly.

• Lubricate all components liberally with hydraulicfluid during assembly.

• Always install new O-rings when reassemblingcomponents.


9-50 D704-WOO Dec. 2004

• Make sure that flat on speed control valve lines upwith flat on the inside of the cover.

• Secure the head to the body with socket head capscrews.

• Replace the rubber boot on the speed control shaft.

704W966A

704W967A

(1) Cover (3) Flat

(2) Flat


(2) Body

(3) Head

(4) Speed Control Shaft

(5) Rubber Boot

• Make sure that the balancing passage in the spoolis facing the cap of the spool valve.

704W965A

(1) Spool (3) Body

(2) Balancing Passage (4) Cap

HYDRAULIC SYSTEM

9-51D704-WOO Dec. 2004

704W968A

704W969A

6.4 CHECK AND ADJUSTMENT

A. Hydraulic Cylinder Bore1. Check the cylinder’s inside surface for scratchs or

damage.

2. Using a cylinder gauge, measure the cylinder I.D.

3. If the measured valve exceeds the allowable limits,replace the hydraulic cylinder block.

B. Clearance Relationship Between HydraulicArm Shaft and Bush

1. Using a O.D. micrometer, measure the hydraulicarm O.D.

2. Using a I.D. micrometer, measure the bush I.D. andthen calculate the clearance.

3. If the calculated clearance exceeds the allowablelimits, replace the bush.

CylinderI.D. (A)

90.000 ~ 90.050 mm

3.54330 ~ 3.54527 in.

90.150 mm

3.54921 in.

Referencedimension

Allowablelimit

Hydraulicarm shaftO.D.

49.970 ~ 49.940 mm

1.96732 ~ 1.96614 in.

44.975 ~ 44.950 mm

1.77066 ~ 1.76968 in.

Right (A)

Left (B)

Bush I.D.(Afterassembled)

50.075 ~ 50.115 mm

1.97145 ~ 1.97303 in.

45.075 ~ 45.115 mm

1.77460 ~ 1.77618 in.

Right (A1)

Left (B1)

Clearancebetweenhydraulicarm shaftand limitbush

0.125 ~ 0.230 mm

0.00492 ~ 0.00906 in.

0.50 mm

0.0197 in.

0.125 ~ 0.220 mm

0.00492 ~ 0.00866 in.

0.50 mm

0.0197 in.

Right

Left

Referenceallowable

Allowablelimit

Referencedimension

Allowablelimit


9-52 D704-WOO Dec. 2004

704W971A

704W970A

C. Reaction Spring Assembly Reference Dimen-sion

(1) Spring (3) Nut

(2) Hex. Bolt

D. Dimensional Setting of Position Control Bolt1. When assembling the control valve (MLS valve) into

power lift body, “A” dimension will be 112 mm.

2. If adjusting the control bolt (1), loosen nut (2) andthen tighten-lock nut (2).

Reaction springassembly initlallength (L)

50 mm

1.9685 in.

Referencedimension

“A” Settinglength

112 mm

4.4094 in.

Referencedimension

“B” Settinglength

50.5 mm

1.9881 in.

Referencedimension

(1) Control Bolt

(2) Nut

HYDRAULIC SYSTEM

9-53D704-WOO Dec. 2004



(3) Position Control Shaft

(4) Hex. Bolt

(5) Lifting Arm

[A] Hydraulic Lifting Arm at End of Stroke

[E] Back Stop

[F] Back Stop

E. Lever Position Setting

a. Adjustment of Position Control LeverThe position control lever can be adjusted with a smallload applied to the elevating arm.

1. Loosen the position control shaft (3), and lever tight-ening bolt (4).

2. Using a 13 mm spanner, rotate the position controlshaft (3) counterclockwise until the elevating armhas stopped to climb by the inside hydraulic limit.Because of safety, the area, although the elevatingarm is at it’s maximum angle, will never contact thehydraulic limit switch.

3. Elevate the lever up and down two or three times.Check it for operation and make sure it is located atthe same position that you set it at.

4. With minimum rpm, lower the position control lever(6) to the stopper (8), and then slowly raise the Draftcontrol lever (5) toward the stopper (7) so that theelevating arm might be raised.

5. Decrease and adjust the length (L) of feedback rodgradually one rotation a time, until the rod smoothlowers.

6. After a completion of the adjustment, tighten the nut(1) and lock bolt (2).

(Ref.)

When raised to max. using the Draft control lever, height(H) will be higher between 15 and 20 mm (0.59 ~ 0.79 in.)than the max, using the position control lever.

Length offeedback rod (L)

135 mm

5.3149 in.

Referencedimension

b. Draft Control Lever (If equipped)1. Lower the elevating arm, loosen the lock nut (1)

and push backward.

2. Disengage the lock bolt (2).

3. Adjust the length of the feedback rod.

(1) Nut

(2) Bolt

(3) Position Control Shaft

(4) Hex. Bolt



(7) Stopper

(8) Stopper

704W972A

704W973A


9-54 D704-WOO Dec. 2004

F. Sensibility AdjustmentPosition the rockshaft lifting arms, with a weight applied,so that they reach about half their angular movementrange.

In this way the Control Valve is positioned in its neutralphase.

Loosen nut “A” and turn the embedded hexagonalscrew “B” in a counterclockwise direction until the lift-ing arms start swaying continuously.

With a slow movement stop the movement of the armsby rotating screw “B” in a clockwise direction.

When the arms remain blocked in their position, whichcan be controlled with the relevant instrument posi-tioned on the end of the lifting arm, rotate (clockwise)the screw “B” for 1/2~3/4 of a turn max. Lock the posi-tion with the self-locking nut “A”.

In this way the Control Valve is sensitivity adjusted.

704W974A

(A) Nut (B) Screw

Documents

ck30 WM 09 Hydraulicdemss.co.kr/dossfile/manualn/WMFILE/CK25/CK30_WM_09... · 2006. 7. 26. · CHAPTER 9 CK25(H)/30(H) 9-4 D704-WOO Dec. 2004 1.2 HYDRAULIC CIRCUIT DIAGRAM OF 3-POINT