Part of the JCB Repair Manuals.
Tracking down a gremlin in the electrical system or rebuilding the main relief valves on your mini-excavator requires the exact factory data found inside the 255-page JCB 802.7, 803, 804 service manual PDF (OEM #9803/3110). Inside, you get complete hydraulic schematics detailing the pump operation and rotary coupling, along with full wiring diagrams for the alternator and starter circuits. Expect detailed teardowns for the track gearbox, slew gearbox, and engine, backed by exploded views showing every ram pivot and boom linkage. Verify the starter motor commutator diameter is exactly 32 mm before reinstalling, and always tighten the track motor retaining bolts to a solid 113 Nm. A broken machine burns daylight and costs you money. Download this bookmarked file straight to your tablet, jump to the correct troubleshooting chart, and get those tracks moving again.
Other edition of this manual
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| Hydraulics | 2-14 | Hydraulic Circuit (Schematic), Servo Circuit |
| General Information | 15-22 | |
| Service Schedules | 23-25 | |
| Greasing | 26-47 | |
| Hydraulic Pump - Operation | 48-57 | |
| Hydraulic Pump | 58-92 | |
| Main Relief Valves | 93-98 | |
| Rams | 99-108 | |
| Rotary Coupling | 109-112 | |
| Pressure Testing | 113-127 | |
| Options | 128-137 | Iso to 3CX Conversion Option |
| Body & Framework | 138-151 | Boom, Bucket, Ram Pivot and Linkage, Dipper, Kingpost |
| Engine | 152-197 | Technical Data, Fuel Lift Pump, Fuel Injectors and Fuel Pipe Assembly, Water Pump / Thermostat Housing Assemblies, Cylinder Head, Piston and Connecting Rods, Crankshaft |
| Gearboxes | 198-215 | Track Gearbox, Slew Gearbox |
| Track & Running Gear | 216-229 | Tracks, Track Rollers, Idler and Recoil Unit |
| Electrics | 230-250 | Alternator, Starter Motor, Circuit Diagram |
| Service Tools | 251 |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Track motor to undercarriage Retaining bolts torque | 113 Nm | p. 18 |
| Battery Voltage | 12V | p. 230 |
| Battery Capacity | 70 ampere/hour | p. 230 |
| Starter Motor Torque (on-load) | 15.69 Nm (1.6kgf/m, 11.57lbf/ft) | p. 230 |
| Starter Motor Commutator Diameter | 32 mm (1.26in) | p. 242 |
| Hydraulic Fitting Adapter Torque (SAE Tube Size 4) | 20-28 Nm | p. 20 |
| Hydraulic Fitting Adapter Torque (SAE Tube Size 6) | 46 - 54 Nm | p. 20 |
| Track Hydraulic Motor O-ring/oil seal replacement | Renew the O-ring 3, spring pin 5 and oil seal 22 | p. 68 |
| Track Motor oil leakage O-rings/gasket replacement | replace O-rings and and gasket | p. 69 |
| Fuel Tank Capacity | 50 L | p. 16 |
| Engine Oil Capacity (after first 100 hours) | 4.5 L | p. 16 |
| Track Gearbox Oil Capacity (each) | 1.2 L | p. 16 |
