MH-S-MF70,80

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Service ManualMF70 & MF80

Tractor, Loader & backhoe

THIS IS A MANUAL PRODUCED BY JENSALES INC. WITHOUT THE AUTHORIZATION OF MASSEY HARRIS MASSEY FERGUSON OR IT’S SUCCESSORS. MASSEY HARRIS MASSEY FERGUSON AND IT’S SUCCESSORS

ARE NOT RESPONSIBLE FOR THE QUALITY OR ACCURACY OF THIS MANUAL.

TRADE MARKS AND TRADE NAMES CONTAINED AND USED HEREIN ARE THOSE OF OTHERS, AND ARE USED HERE IN A DESCRIPTIVE SENSE TO REFER TO THE PRODUCTS OF OTHERS.

Serv

ice

Man

ual

MF 70,AND MF 80 - BACKHOE LOADER

PART 1 - General Service Information and Recommendations

PART 2 - Engine

PART 3 ~ Torque Converter and Transmission

PART 4 - Dri,!e Axle - Including Brakes and Rear Wheel Installation

PART 5 - Brake and Differential Lock Hydraulics

PART 6 - Front Axle and Steering Hydraulics

PART 7 - Loader and Backhoe Hydraulics

PART 8 - Electrical Systems

Form No. 1448 839 M 1 Printed in U.S.A.

PART 2 - ENGINE

Contents

SECTION

A4.318 ENGINE ..................................................................................... A

A6.3541 ENGINE .................................................................................... B

INTRODUCTION

This part of the Manual consists of two sections of service information for the A4.318 and A6.3541 Engines in­stalled in MF 70 and MF 80 Backhoe Loaders respectively.

Thoroughly clean engine before disassembling it, or removing any component parts of fuel system. Also, cap or otherwise cover all fuel openings to prevent dirt from entering fuel system. Cleanliness is very important and cannot be overemphasized.

Whenever fuel system components are removed, or fuel line connections are disturbed, make sure to bleed fuel system of air before attempting to start engine.

Always disconnect batteries when servicing machine.

SECTION A - A4.318 ENGINE

INDEX

PAGE PAGE

SPECIFICATIONS ............................ 2 Crankshaft and Main Bearings ............. 23 General Specifications ..................... 2 Crankshaft End-Play ..................... 24 Torque Tension Specifications .............. 2 Regrinding Crankshaft ................... 24

Rear Crankshaft Oil Seal ................... 26 SERVICE INFORMATION ..................... 3 Engine Flywheel .......................... 27

Engine Overhaul Specifications. .. . . . . .. . . .. 3 Lubrication System Specifications .......... 5 LUBRICATION SySTEM ...................... 28 Fuel System Specifications ................. 5 Engine Oil ................................ 28 Cooling System Specifications .............. 6 Oil Pressure .............................. 28 Introduction ............................... 7 Oil Pan ................................... 28 Engine Serial Number ..................... 7 Lubricating Oil Filter ....................... 29 Service Tools ............................. 7 Oil Pump ................................. 29

ENGINE OVERHAUL PROCEDURES ..... '...... 7 FUEL AND AIR SYSTEM ..................... 31 Removal.................................. 7 Air Cleaner ............................... 31 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8 Air-Bleeding the Fuel System .............. 32 Valve Clearance Adjustment ............... 8 Fuel Lift Pump ............................ 33 Cylinder Head ............................. 9 Fuel Filters ............................... 34 Valve Guides .............................. 10 Fuel Injection Pump ....................... 35 Valves .................................... 10 Checking and Adjusting Engine Valve Seats ............................... 11 Speed ................................ 36

Installing Exhaust Seat Inserts ........... 11 Checking and Adjusting Fuel Injection Valve Springs ............................. 12 Pump Timing .......................... 37 Rocker Arm Shaft Assembly . . . . . . . . . . . . . . .. 12 Fuel Injectors ............................. 38 Cylinder Head Reassembly ................. 13 Trouble-Shooting ........................ 38 Pistons and Connecting Rods ............... 14 Servicing Injectors ....................... 39 Cylinder Liners ............................ 17 Fuel Lines ................................ 45 Timing Gear Cover and Front

Crankshaft Oil Seal ...................... 18 COOLING SYSTEM .......................... 45 Timing Gears ............................. 19 Fan Belts ................................. 45

Installation and Retiming ................ 21 Thermostat ............................... 45 Camshaft ................................. 21 Water Pump .............................. 46

Checking Valve Timing ................... 22 Timing Gear Housing ...................... 23 ENGINE TROUBLE-SHOOTING ............... 48

-1-MF 70/MF 80 - ENGINE

SPECIFICATIONS

General Specifications for A4.318 Engine

Bore ....................................................................................... 4.5 inches Stroke ....................................................................................... 5 incHes Number of Cylinders ................................................................................. 4 Firing Order ................................................................................... 1-3-4-2 Total Piston Displacement ............................................................. 318 cubic inches Compression Ratio ........................................................................... 1 7.5 to 1 Combustion System .................................................................... Direct injection Engine Flywheel Horsepower* .......................................................... 84 at 2000 rpm Maximum Engine Horsepower** ....................................................... 108 at 2400 rpm Maximum Engine Torque ............................................................. 242 at 1300 rpm Low Idle Speed ........................................................................... 750-800 rpm Rated Engine Speed ......................................................................... 2000 rpm Maximum Engine Speed (No-Load) ..................................................... 2170-2200 rpm Valve Tappet Clearance (Intake and Exhaust) ....................... 0.010 inch "hot" - 0.012 inch "cold"

*Net hp at flywheel of standard engine operating under ambient conditions of 85° F. and 29.38" Hg. equipped with fan, air cleaner, muffler, water, oil and fuel injection pumps, generator (or alternator) and air compressor not charging.

**Maximum gross BHP of engine under the conditions defined in SAE Engine test code J816 (a) 1963.

Torque TensionSpecifications*:

Cylinder Head ............................................................................ 85-90 ft.-Ibs. Connecting Rods ....................................................................... 1 00-1 05 ft.-Ibs. Main Bearings ......................................................................... 140-150 ft.-Ibs. Flywheel ................................................................................. 74-80 ft.-Ibs. Crankshaft Pulley ...................................................................... 280-300 ft.-Ibs. Rocker Shaft Brackets .................................................................... 21-24 ft.-Ibs. Intake and Exhaust Manifolds ............................................................. 12-15 ft.-Ibs. Injection Pump Drive Gear ................................................................ 19-21 ft.-Ibs. Camshaft Gear ........................................................................... 41-45 ft.-Ibs. Idler Gear Hub ........................................................................... 21-24 ft.-Ibs.

OIL PAN: Oil Pan to Cylinder Block ........................................................ , ......... 19-21 ft.-Ibs. Oil Pan to Timing Gear Housing ........................................................... 12-15 ft.-Ibs. Oil Pan to Rear Bridge Piece .............................................................. 10-15 ft.-Ibs. Injector Hold-Down Nuts .................................................................. 10-12 ft.-Ibs.

OIL FILTER: Oil Filter Bowl .............................................................................. 10 ft.-Ibs. Oil Filter to Cylinder Block ................................................................ 26-30 ft.-Ibs.

*THESE TORQUES APPLY WITH THE THREADS CLEAN AND LIGHTLY OILED. DO NOT EXCEED THESE VALUES AS DAMAGE COULD OCCUR.

-2-

Fig. 29 - Removing or Installing Camshaft

, 6. Remove camshaft complete with gear and thrust washer from cylinder block, Fig. 29. Be care­ful not to damage bearing journals or cam lobes when withdrawing camshaft.

INSPECTING CAMSHAFT

1. Thoroughly clean camshaft and inspect bearing journals and cam lobes for wear or damage. If journals are scored, nicked or discolored by heat, or if lobes are pitted or rough, camshaft should be replaced.

2. Measure diameter of bearing journals for wear and out-of-round. If journal diameters or camshaft lobes are badly worn, camshaft should be replaced.

3. Measure camshaft bearing bores in cylinder block. Then compare each bore diameter to its mating journal diameter. Correct clearance between Nos. 1 and 2 camshaft bearing journals and their bores is 0.002-0.005 inch. No.3 camshaft journal should have 0.004-0.007 inch clearance.

Fig. 30 - Installing Camshaft Thrust Plate

Fig. 31 - T.D.C. Timing Mark Aligned with Indicator

4. With camshaft gear and thrust plate installed onto camshaft, use a feeler gauge and measure clearance on both sides of thrust plate. Remove camshaft gear and install a new thrust plate, if clearance exceeds 0.018 inch. Fig. 30 shows instal­ling a new thrust plate with camshaft installed in place.

During overhaul, tappets should be removed and given an inspection. If any tappets have uneven wear on cam follower face, it is an indication that tappet has not been rotating in its bore. Replace tappets with badly worn faces. New tappets should be in­stalled whenever camshaft is replaced.

Do not attempt to reclaim tappets by regrinding faces.

INSTALLING CAMSHAFT

To install camshaft lubricate journals and lobes with oil and proceed as follows:

1. With engine upside down or with tappets sup­ported in their fully raised position, carefully in­stall camshaft (with gear attached to it) into cyl­inder block. See Fig. 29.

2. Install capscrews and lockwashers securing thrust plate to cylinder block.

3. Install engine idler gear, making sure all tim­ing gear marks are aligned.

4. Install push rods and rocker arm shaft assembly. Adjust valve clearances.

5. Install fuel pump, timing gear cover and com­plete reassembly of engine.

CHECKING VALVE TIMING

To check valve timing of engine, proceed as fol­lows:

1. Rotate crankshaft in normal direction of en­gine rotation (clockwise) until both rocker arms of No.4 cylinder are "rocking" (exhaust valve closing and intake valve opening).

NOTE: At this point No. 1 piston will be at approximately T.D. C. on compression stroke.

2. With crankshaft positioned with No. 1 cylinder at T.D.C. on compression stroke, adjust INTAKE VALVE CLEARANCE of No.1 cylinder to 0.020 inch.

-22-

SECTION B - A6.3541 ENGINE

INDEX

PAGE

INTRODUCTION

ENGINE DATA AND PROCEDURES FOR MF 80 .............................. 2 Specifications ........................................................... 2

General Specifications ................................................. 2 Lubrication System Specifications ...................................... 2 Fuel and Air System Specifications ..................................... 3 Cooling System Specifications .......................................... 3

Engine Component Identification and Servicing ............................ 4 Engine Removal and Installation .......................................... 6 Radiator Removal and Installation ........................................ 8 Fuel and Air System Servicing ........................................... 9

Fuel Filter Element Replacement ....................................... 9 Air-Bleeding Fuel System .............................................. 10

Engine Controls Adjustments ............................................. 11 Fuel Shut-Off Control Adjustment ...................................... 11 Engine Speed Adjustment .............................................. 11 Hand Throttle Adjustment .............................................. 12 Foot Pedal Throttle Adjustment ......................................... 12

ENGINE SERVICING INFORMATION .............. Refer to Publication within this Section titled "Workshop Manual for 6.372, 6.3542, T6.354

and 6.354 Engines"

INTRODUCTION

This Section consists of two portions of service information concerning the A6.3541 EnginefortheMF80. FOR COMPLETE INFORMATION BOTH PORTIONS MUSTBE USED TOGETHER.

The first portion, "Engine Data and Procedures for MF 80", contains information specific to the MF 80.

The second portion contains a separate engine publication titled "Workshop Manual for 6.372, 6.3542, T6.354 and 6.354 Engines". This publication is a basic service manual covering several different models of engines. Section P, "Turbocharger", does not apply to this unit and has been omitted. The information for Section Q, "Alternator and Starter Motor", is included in Part 8 - Electrical System.

Right and left-hand sides of engine and machine are referred to as viewed from rear of flywheel. Direction of engine rotation is viewed from crankshaft pulley end of engine.

For torque converter to flywheel attachment information refer to Part 3.

Fig. 1 - Left Side View of A6.3541 Engine Fig. 2 - Right Side View of A6.3541 Engine

-1-MF 70/MF 80 - ENGINE

CONTENTS

Section

ENGINE DESCRIPTION A

TECHNICAL DATA B

PREVENTIVE MAINTENANCE C

FAULT DIAGNOSIS D

CYLINDER HEAD E

PISTONS AND CONNECTING RODS F

CYLINDER BLOCK AND LINERS G

CRANKSHAFT AND MAIN BEARINGS H

TIMING CASE AND DRIVE J

LUBRICATING SYSTEM K

COOLING SYSTEM L

AIR CLEANERS AND FUEL SYSTEM M

FLYWHEEL AND HOUSING N

TURBOCHARGER P

ALTERNATOR AND STARTER MOTOR Q

LUBRICA TING SYSTEM-K.2

Lubrication for the timing gears is taken from the oil passages connecting the pressure rail with the front main bearing and auxiliary drive. The two idler gear hubs intersect these drillings and oil is passed through the hubs to radial drillings in the idler gears to lubricate the teeth of the gear train.

The auxiliary drive shaft bearings are lubricated by a drilling from the pressure rail to the front auxiliary drive shaft bearing. The oil then passes around a groove in the bearing journal and through a further drilling along the outer side of the auxiliary drive housing to the rear auxiliary drive shaft bearing. Lubricant for the upper fuel pump drive bearing is also taken from this drilling. Also connected with the outer drilling is a small spray tube, which directs oil onto the wormwheel and worm gear.

SUMP

An exploded view of the lubricating oil sump and pump is shown in Fig. K.2.

To Remove the Sump Lower the sump by releasing all flange set­

screws.

To Replace the Sump I. Screw two guide studs In the cylinder block.

one on each side. Place the sump in position and insert the screws. Remove the guide studs .

.I. Tighten the screws evenly to a torque 9110 Ihf ft (1.211.4 kgf m).

OIL PUMP

To Remove the Oil Pump and Oil Pump Delivery Housing

I. Remove the sump and strainer. .., Remove the two setscrews securing the oi 1

delivery housing to the cylinder block. 3. Unscrew the lubricating oil pump locating

setscrew situated on the outside of the cylinder block.

4. The oil pump and oil delivery housing can now be removed (Fig. K.3).

5. The two parts of this assembly are connected by a short pipe which is a push fit in each compartment. A rubber '0' ring is recessed into the bore of both the lubricating oil pump and the delivery housing and to separate, Dull the components apart.

Fig. K.3. Lubricating Oil Pump Removal.

Fig. K.4. Checking Clearance between Inner and Outer Rotor.

I. Shaft. 3. Outer Rotor. 2. Inner Rotor. 4. Pump Bodv.

TABLE OF CONTENTS

HOW THE UNITS OPERATE

SECTIONAL VIEWS AND PARTS IDENTIFICATION

Basic Design Silhouette

Converter Assembly

Converter and Transmission Case Group

Two Speed Case and Clutch Group

Clutch Group

Mechanical Parking Brake

Regulating Valve, Charging Pump and Filter Group

Control Valve Assembly

Typical 28,000 Cross Section

External Plumbing Diagram •

Typical Two Speed Power Flow

Ring Gear Installation

Shielded Bearing Installation

DISASSEMBLY OF TRANSMISSION

Fig. A

Fig. B

Fig. C

Fig. D

Fig. E

Fig. F

Fig. G

Fig. H

Fig.

Fig. J

Fig. K

Fig. L

Fig. M

CLEANING AND INSPECTION 12

REASSEMBLY OF TRANSMISSION 13

SERVICING MACHINE AFTER TRANSMISSION OVERHAUL 24

SPECIFICATION AND SERVICE DATA 25

LUBRICATION • 25

TROUBLE SHOOTING GUIDE 25

NOTE: Metric Dimensions Shown in Brackets [ J.

PART 4 - DRIVE AXLE -INCLUDING BRAKES AND REAR WHEEL INSTALLATION

CONTENTS

PAGE

FASTENER TORQUE VALUES ..................................................................... 2

GENERAL SPECiFiCATIONS ....................................................................... 2

INSPECTION AND SERVICE NOTES ................................................................ 2

WHEEL HUBS .................................................................................... 2 Removal ....................................................................................... 2 Installation ..................................................................................... ' 3

DRIVES HAFT ASSEMBLY ......................................................................... 3

PARKING BRAKE ASSEMBLY ..................................................................... 4

DRIVE AXLE ASSEMBLY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4 Removal ....................................................................................... 4 Insta lIation .............................................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4

AXLE HOUSING ASSEMBLY ...................................................................... 6 Removal ....................................................................................... 6 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6

PLANETARY ASSEMBLy ......... " .. , ................. " . . . . .. . .... . . ..... . . ... .... .. .. .... .. .. .. 6 Removal and Disassembly ...................................................................... 6 Assembly and Installation ....................................................................... 8

AXLE SHAFT ASSEMBLY ......................................................................... 10 Removal ....................................................................................... 10 Installation ..................................................................................... 10

BRAKE SERVICING ............................................................................... 11

DIFFERENTIAL ASSEMBLY ........................................................................ 12 Removal ................................................................................. , ..... 12 Installation ..................................................................................... 12 Differential Lock Servicing ...................................................................... 13

Disassembly ................................................................................. 13 Reassembly .................................................................................. 13

Disassembly ................................................................................... 14 Inspection ..................................................................................... 15 Ring Gear Servicing ............................................................................ 15 Assembly ...................................................................................... 15

DRIVE PINION ASSEMBLY ........................................................................ 16 Removal ....................................................................................... 16 Installation ..................................................................................... 17

-1-MF 70/MF 80 - DRIVE AXLE

PART 5 - BRAKE AND DIFFERENTIAL LOCK HYDRAULICS

Contents

PAGE

SERVICE INFORMATION .......................................................................... 1 Inspection Recommendations ................................................................... 1 Hydraulic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1

PUMP SERVICING ................................................................................ 4 Specifications .................................................................................. 4 Removal/Installation ........................................................................... 4 Disassembly/Inspection/Reassembly ............................................................ 4

BRAKE CONTROL VALVE SERVICING ................................... " ......................... 6 Removal/Installation ........................................................................... 6 Disassembly/Inspection/Reassembly ............................................................ 6

DIFFERENTIAL LOCK VALVE SERViCiNG ........................................................... 7

"BLEEDING" THE BRAKE SYSTEM ................................................................ 8

TESTING THE HYDRAULIC SYSTEM ............................................................... 9 Pressure and Flow Reference Chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 Checking System Pressures ..................................................................... 9 Testing Pump Efficiency and Flow Divider Setting ............. ;................................... 9

SERVICE INFORMATION

1. Perform recommended tests before attempt­ing repair.

2. Prior to removing ANY hydraulic component, measures must be taken to prevent dirt and dust from entering system.

CAUTION: Observe safety precau­tions to avoid possible injury to per­sonnel. Before attempting to remove (or disconnect) a hydraulic com-ponent, make certain that hydraulic pressure is relieved. The bucket should be flat on the ground and control levers operated back and forth several times with engine NOT RUNNING.

3. If system oil is to be drained and reused, be sure drain containers are clean and are covered when not in use.

Inspection Recommendations

These procedures apply generally to all assemblies and components covered within this Part. They are in addition to any specific instructions.

1. Clean all assemblies and components prior to removal.

2. Use extreme care to prevent dirt from entering system.

3. Clean all metal parts with a suitable fluid and air dry prior to reassembly.

4. Replace ALL seals, gaskets and "O"-rings with new items.

5. Inspect all parts for visual evidence of wear, or damage. In many instances it will require the judgment of the serviceman to determine necessity of replacing parts due to wear ... this may be done by comparing tolerances given for NEW parts with dimensions of SUSPECTED "worn" parts.

Hydraulic System

Brake and differential lock share the same hy­draulic systems as illustrated in Fig. 1. If differential lock is NOT installed, brake system is as illustrated in Fig. 2.

Both circuits use the same oil reservoir, filter and hydraulic pump. However, pressures within these circuits differ.

BRAKE CIRCUIT

This is an hydraulic power assist circuit ... con­trolled by an open-center (spool) valve. Flow is sup­plied to brake valve by a flow divided pump. When brake valve is actuated (by depressing pedals), oil is supplied to brake pistons located in left and/or right rear axle assemblies. Pressure in circuit is proportional to applied pedal effort. An equalizing valve engages when both pedals are depressed, and has an output at lowest pressure determined by either left or right brake spool.

Manual braking is accomplished when engine is "off', by pumping pedals.

Parking brake service information and procedures are contained in Part 4.

-1-MF 70/MF 80 - BRAKE & DIFFERENTIAL LOCK

PART 6 - FRONT AXLE AND STEERING HYDRAULICS

INDEX

PAGE

IMPORTANT INSPECTION RECOMMENDATIONS ............................ 1

GENERAL SERVICE INFORMATION ......................................... 1 Hydraulic Components and System Flow .................................. 2

RESERVOIR ............................................................... 2

PUMP SERVICING ......................................................... 3 Removal/Installation .................................................... 3 Disassembly/Inspection/Reassembly ..................................... 3

CONTROL VALVE (WITH HAND PUMP) SERVICING .......................... 4 Removal/Installation .................................................... 5 Disassembly/Inspection/Reassembly ..................................... 5

HYDRAULIC CYLINDER SERVICING ......................................... 7 Removal/Installation .................................................... 8 Disassembly/Inspection/Reassembly ..................................... 8

FRONT AXLE SERVICING .................................................. 9 Removal of Axle Assembly ............................................... 9 Servicing/Installation .................................................... 10 Removal/Installation of Spindle(s) Assembly .............................. 11 Wheel Bearing Adjustment (and Repacking) ............................... 12 "Toe-In" Adjustment .................................................... 13

TESTING SySTEM ....................................................... ·· 13 Checking System Pressures .............................................. 13 Testing Pump Efficiency and Flow Control Setting ......................... 13

IMPORTANT INSPECTION RECOMMENDATIONS

The "common sense" service and inspection pro­cedures are outlined below and apply generally to all assemblies (and components) covered within this Part. These procedures are not repeated under the servicing of individual parts and are in addition to any given specific instructions.

Clean all assemblies (and components) prior to removal.

Take all necessary precautions to prevent dirt from entering system.

Clean all metal parts prior to reassembly (using a suitable fluid) and blow dry with compressed air.

Inspect all parts for evidence of wear or damage (in many instances, it will require the judgment of the serviceman to determine necessity for replacement of parts due to wear).

It is good service practice to replace all seals, gas­kets and "O"-rings with new items.

GENERAL SERVICE INFORMATION

Perform appropriate tests under "Testing System" before attempting repair.

Prior to removing any hydraulic component, nec­essary measures must be taken to prevent dirt and dust from entering system.

CAUTION: Observe safety precautions to avoid possible injury to personnel. Before attempting to remove or dis­connect any hydraulic component. make certain that hydraulic pres­sure is relieved. The bucket should be flat on the ground and control levers operated back and forth several times with engine not running. If system oil is to be drained and re­used. be sure drain containers are clean and are covered when not in use.

MF 70/MF 80 - FRONT AXLE & STEERING -1-

PART 7 - LOADER AND BACKHOE HYDRAULICS

Contents

PAGE

CHANGES AFFECTING SERVICE INSTRUCTIONS

SERVICE INFORMATION ......................................................................... . 2 Inspection Recommendations .................................................................. . 2 Hydraulic System - See "Changes Affecting Service Instructions" ............................... . 2

RESERVOIR SERVICING ......................................................................... . 7 o.

Breather-Regulator Valve Servicing ............................................................. . 7

FILTER SERVICING .................................................................... '0_' h'-' •••••• 8 Reservoir Filter ................................................................................ . 8 Return Line Filter .................................................................. -........... . 10

PUMP SERVICING ............................................................................... . 10 Removal/Installation .......................................................................... . 10 Disassembly/Inspection/Reassembly ........................................................... . 10

RELIEF VALVE SERVICING - See "Changes Affecting Service Instructions" ......................... . 14

LOADER CONTROL VALVE SERVICING ........................................................... . 16 Removal/Installation .......................................................................... . 17 Disassembly/Inspection/Reassembly ........................................................... . 18

BACKHOE "LIFT" VALVE SERVICING - See "Changes Affecting Service Instructions" ............... . 18 Removal/Installation .......................................................................... . 18 Disassembly/Inspection/Reassembly ........................................................... . 20

BACKHOE "SWING" VALVE SERViCiNG .......................................................... . 24 Removal/Installation .......................................................................... . 24 Disassembly/Inspection/Reassembly ........................................................... . 24

HYDRAULIC CYLINDER SERVICING ............................................................... . 25 Disassembly/Inspection/Reassembly .............................. ' ............................. . 25

SWING CYLINDER FLOW CONTROL BLOCK SERVICING ........................................... . 29 Disassembly/Inspection/Reassembly ........................................................... . 29

"UNLOAD VALVE" ADJUSTMENT - MF 70 - See "Changes Affecting Service Instructions" ........ . 30

TESTING SySTEM ............................................................................... . 31 Operational Check of Hydraulic System ......................................................... . 31 Checking Main Reliefs - See "Changes Affecting Service Instructions" ........................... . 32 Checking Circuit Reliefs ........................................................................ . 33 Testing Pump Efficiency ....................................................................... . 33 Testing "Lift" Checks (within Control Valve) ..................................................... . 33 Testing for Spool Leakage ...................................................................... . 34 Testing for Internal Leakage of Cylinders ........................................................ . 34

TROUBLE-SHOOTING CHARTS ................................................................... . 35 Component Symptoms ......................................................................... . 35 Loader Symptoms ............................................................................. . 35 Backhoe Symptoms ............................................................................ . 35

SPECiFiCATIONS ................................................................................ . 37 Pressure and Flow Reference Chart ............................................................. . 37 Control Spool Travel Chart ..................................................................... . 38 Cycle Times (Normally Expected) ............................................ ' .................... . 38 Cylinders ................................................................................... .' .. 38

MF 70/MF 80 - LOADER & BACKHOE HYDRAULICS -i-