1970s–1980s JCB MK2 & MK3 Excavator Loader Workshop Manual

This JCB workshop manual covers the 1970s–1980s MK2 and MK3 excavator loader range, including 2D, 2DS, 3, 3C, 3CS, 3D, and 700 models with manual or torque converter transmissions.

• Engine and maintenance: Engine removal and installation, fuel-system bleeding, filter service, cooling-system maintenance, lubrication charts, and build-specific service schedules.

• Hydraulic repair: Hamworthy and Commercial pump overhaul, loader and excavator valve service, relief-valve pressure testing, cylinder seal replacement, and fault finding.

• Transmission service: Manual and synchromesh gearbox repair, /3 torque converter diagnosis, clutch inspection, final-drive adjustment, and selected /5 shuttle transmission material.

• Brakes and steering: Dry and oil-immersed brake service, hydraulic brake bleeding, Plessey and Danfoss steering-unit overhaul, and internal-leakage tests.

• Electrical diagnosis: Starter and charging-system tests, fault charts, and market-specific wiring diagrams with component keys and wire-color codes.

• Attachments and framework: JCB Roadbreaker service, Powerbreaker nitrogen charging, extending-dipper removal, slew-actuator overhaul, and boom, dipper, and kingpost removal.

The manual was written primarily for JCB distributor service engineers, with procedures that use workshop lifting equipment, pressure gauges, and component-specific service tools.

Routine Service and Engine Coverage

Service schedules distinguish manual, /3, and /5 builds. Fuel-system coverage includes Simms Minimec and CAV DPA bleeding arrangements, injector removal, and fuel-lift-pump maintenance; lubrication tables distinguish engine sump and brake configurations.

Reference tables provide component torque settings, tire pressures, and electrical test data, supported by component section views and dimensional drawings.

Engine overhaul scope: The engine section covers removal and installation. Internal engine dismantling and assembly require the separate Leyland 38TD and 4/98 NT Engine Service Manual, which is not included.

Hydraulic and Steering Diagnosis

Hamworthy and Cessna loader valves receive separate service instructions. Hydraulic circuit drawings for JCB 2D/3/3C and 3D accompany troubleshooting for slow operation, loss of power, and excessive slew overrun.

Plessey gear-pump checks and steering pressure tests help distinguish pump or relief-valve faults from internal leakage in the steering unit or cylinder before component removal. Danfoss Orbitrol and Plessey steering units have separate overhaul instructions.

The seal-handling notes warn that trichloroethylene or paint thinner can severely damage certain rubber seals and O-rings.

Gearboxes, Final Drives, and Brakes

Torque converter circuit views and synchromesh operating diagrams support the transmission procedures. Shaft removal, selector checks, bearing preload, and crownwheel-and-pinion adjustment are covered, with separate instructions for suffix R modified gearboxes.

/5 powertrain scope: Coverage includes a shuttle assembly illustration, forward-clutch and drive-gear assembly information, gearbox fault finding, and drive-axle settings. These pages do not provide a complete /5 shuttle or gearbox overhaul sequence; the forward-clutch spacer-selection instruction is also incomplete.

Brake procedures distinguish mechanically operated skid brakes from hydraulic powertrain brakes. The oil-immersed /5 system has different fluid requirements from the dry-brake version; the manual warns that incorrect fluid can seriously damage the brake system.

Electrical Fault Tracing

The electrical section covers Lucas M50 starter repair, Lucas 18ACR and AC Delco DN460 alternator tests, dynamo service, and regulator adjustment. Standard/American, Austrian, German, and Swedish wiring layouts are organized by machine range, alongside starting, charging, and lighting fault charts.

Attachments and Structural Work

Hamworthy flow-divider adjustment and JCB Roadbreaker fault finding address breaker performance. Powerbreaker procedures identify nitrogen filling kit 992/06600, while extending-dipper and hydraulic power take-off sections cover their valves and associated components.

Body and framework procedures include cab glazing and rear-window adjustment. The Care and Safety section addresses support for raised loader arms, heavy-component handling, and trapped hydraulic pressure.

A Preview of Cooling, Valve, and Axle Specifications

The engine data list a cooling-system capacity of 13.6 liters and valve clearance of 0.33 mm (0.013 in), hot or cold.

For the /5 drive axle, the crownwheel backlash check specifies 0.25–0.33 mm (0.010–0.013 in) after adjustment, alongside separate pinion-depth and bearing-preload procedures.

PDF Bookmarks, Diagram Detail, and Page Count

Navigation and wiring detail: Embedded bookmarks open the twelve main sections. PDF text search is unavailable. Small wiring labels require zooming, and some fine circuit lines are faint.

Supplied as one 413-page printable PDF in English. The total includes three introductory pages: the cover, section guide, and preface.