Looking for the factory tear-down steps for your 1993-2004 JCB Loadall? This 587-page JCB 504b, 526, loadall service manual pdf (OEM #9803/3610U-4) delivers exactly how to rebuild the transmission, service the hydraulics, and fix the electrical system. Inside, you get a massive section of hydraulic schematics, full wiring diagrams with relay identification, and complete fault-finding charts for the powertrain. Open up to step-by-step procedures covering everything from the compensating master cylinder to the SS640 transmission torque figures. Set your hydraulic filter relief valve to exactly 1.05 bar and confirm the 8-stud wheel nuts are tightened down to 325 Nm before sending the machine back out. Guessing at fluid pressures burns up pumps and your profit margin. Download this bookmarked file straight to your tablet, click on the exact system you are working on, and get the job done right.
What's Inside This JCB 504B, 526, LOADALL Manual
| System | Pages | Key Topics |
|---|---|---|
| General Information | 1-28 | Identification Plate, Torque Settings, Service Tools, Sealing and Retaining Compounds |
| Care & Safety | 29-36 | Safety Notices, General Safety, Operating Safety, Maintenance Safety, Lubricants - Health and Safety |
| Routine Maintenance | 37-79 | Lubricants and Capacities, Machine Safety, Service Schedules, Grease Every 50 Hours, Grease Every 500 Hours, Oiling, Tires and Wheels, Foot Brake |
| Attachments | 80 | - |
| Body & Framework | 81-110 | Cab - Removal and Replacement, Direct Glazing, Fuel/Hydraulic Tank, Wear Pads, Inner and Outer, Air Conditioning Option, Rivet Nuts |
| Electrics | 111-203 | Technical Data, Relay Identification, Fuse Identification, Test Methods, Proximity Switch, Schematics, Wire/harness Numbers - Explanation of, Wire Number Indentification |
| Controls | 204-205 | Adjusting |
| Hydraulics | 206-267 | Technical Data, 504B Rs Machines and 504B 4 Wheel Steer Machines Up to Serial No. 278610, 526 Machines From Serial No. 280300 with Dual Lever Control |
| Assembly | 272-326 | Descriptions, Technical Data, Towing Procedure, Testing, Fault Finding, Torque Converter, Dismantling, SS640 Section Views and Torque Figures |
| PS750 Section Views and Torque Figures | 327-360 | PS700 Section Views and Torque Figures, Reverser Unit (Later Type) - Dismantling, Reverser Unit (Earlier Type), Reverser Unit (Later Type) - Assembly, Mechanical 4 Wheel Drive Unit - Assembly, Mechanical 4 Wheel Drive Unit - Dismantling, Powershift (with Reverser Shaft Cover Plate) |
| Powershift (with Reverser Shaft Sealing Plug & PS750) | 361-382 | - |
| Layshaft - Dismantling | 383-407 | Input Clutch & Reverser Clutch - Assembly, Input Clutch and Reverser Clutch - Input Clutch, Input Clutch and Reverser Clutch - Dismantling, Mainshaft - Dismantling, Mainshaft - Location of Components, Mainshaft - Assembly, Layshaft - Location of Components |
| Hydraulic 2/4 Wheel Drive Unit | 408-428 | Ps 750 Input & Reverser Clutch - Assembly, Layshaft - Assembly, Ps 750 Input & Reverser Clutch - Dismantling, Powershift PS750, Ps 750 Mainshaft - Assembly, Ps 750 Mainshaft - Dismantling, Ps 750 Layshaft - Assembly, Ps 750 Layshaft - Dismantling |
| Differential | 429-454 | Propshafts, Polytetrafluoroethene (Ptfe) Piston Ring Seals - Fitting Procedure, Permanent 4 Wheel Drive Unit, Solenoid Valve, Output Shaft Removal - Larger Diameter Gears, Collapsible Spacer - Assembly, Rear Hub - Unbraked, Rear Axle |
| Drop Box | 455-502 | Drive Head, Hub and Driveshaft - Dismantling, Pinion, Hub and Driveshaft - Assembly, Hub, Drive Head with Limited Slip Differential, Crown Wheel and Pinion, Brakes |
| Axle Operating Temperature (Oil Immersed Brakes) | 503-507 | Transmission Oil Cooling, 2/4 Wheel Disconnect (If Fitted) |
| Brakes | 508-539 | Technical Data, Compensating Master Cylinder, Power Brake Circuit, Testing the Parking Brake, Parking Brake Adjustment, Brake Discs, Fault Finding, Bleeding |
| Steering | 540-577 | Technical Data, Steer Valve Operation, Priority Valve Operation, Steer System Operation, Fault Finding, Re-Aligning the Road Wheels, Powered Track Rod, Link Arms |
| Engine | 578-587 | Identification, Torque Settings, Service Tools (Numerical List, Section B, Section C, Section E, Section F, Section H, Section K), Sealing and Retaining Compounds |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| Wheel nut torque (8 stud wheels) | 325 Nm (240 lbf ft) | p. 57 |
| Wheel nut torque (5 stud wheels) | 680 Nm (500 lbf ft) | p. 57 |
| Fuel filter element tightening | hand tight only | p. 68 |
| Engine oil filter canister tightening | hand tight only | p. 61 |
| Diverter valve adaptors torque | 100-120 Nm (73.75 - 88.5 lbf ft) | p. 256 |
| Ram end cap torque | 678 Nm (500 lbf ft) | p. 267 |
| Relay specifications | Not found (only identification and general instructions to fit correct type) | p. 113 |
| Solenoid valve knurled nut torque | 10 to 15 Nm (1 to 1.5 kgf m, 8 to 10 lbf ft) | p. 431 |
| 504B & 526 Machines | ||
| Hydraulic filter filtration size | 0.001 in (25 microns) | p. 208 |
| Hydraulic filter relief valve setting | 15 lbf/in² (1.05 bar) | p. 208 |
| 504B From Machine Serial Number 277001 to 279014 | ||
| Fuse rating (Starter relay) | 1 | p. 116 |
| Fuse rating (Heater) | 15 | p. 116 |
JCB 504B, 526, LOADALL Common Problems This Manual Covers
JCB 504B and 526 Loadall boom will not lift under load or hydraulics feel severely weak p. 208
Test the main relief valve operating pressure at the pump outlet. Verify the reading reaches 241 bar as specified on page 208. If pressure drops significantly when the oil heats up, inspect the pump for internal wear. Replace the hydraulic filter cover plate screws and torque to 7 Nm.
Manual Section: Hydraulics - Fault FindingEngine starts but quickly dies or continually turns over without actually firing in cold weather p. 68
Check the fuel system for air leaks or restrictions. Bleed the lines up to the injectors. Inspect the fuel filter element and replace if clogged. When installing the new element, tighten it hand tight only as instructed on page 68. Verify the 160 Litres tank has sufficient clean diesel.
Manual Section: Routine MaintenanceHeavy clunking noise from the axles or excessive vibration felt through the steering wheel during transport p. 57
Inspect all wheel hubs for loose hardware before operating. Verify the roadwheel tightness on 8 stud wheels immediately. Torque all wheel nuts to exactly 325 Nm following the tightening pattern shown on page 57. Check the rims for cracked stud holes if the hardware keeps backing off.
Manual Section: Routine MaintenanceEntire machine goes electrically dead or starter relay clicks repeatedly without turning the engine over p. 113
Measure the main battery voltage across the terminals. Confirm you have a full 12 volts as listed on page 113. Clean heavily corroded ground connections on the chassis. For the 504B up to serial 279014, check the starter relay fuse and replace with a 1 amp rating if blown.
Manual Section: ElectricsFrequently Asked Questions
How do I reset the error code on a JCB 526 telehandler?
To reset error codes on a JCB 526 telehandler, if any diagnostic fault codes are displayed, switch the starter key off and on again. If the fault does not clear, refer to the list of fault codes for further troubleshooting.
What does error code mean on a JCB 504B?
For a JCB 504B, error codes are listed in the Fault Finding Chart for the SLI System. For example, if the 'Display box does not work', a possible cause is a 'Blown fuse', and the remedy is to 'Check fuse 3'.
What are the torque specs for JCB 526 wheel nuts?
For JCB 526 machines, the torque specifications for wheel nuts are 325 Nm (240 lbf ft) for 8 stud wheels and 680 Nm (500 lbf ft) for 5 stud wheels. These should be checked every two hours on new machines or after a wheel has been removed until they stay correct.
What are the replacement specifications for hydraulic filters?
The replacement specifications for hydraulic filters include a 'Partial flow ('spin on')' filter type and a 'Filtration Size' of 0.001 inch (25 microns). The 'Relief Valve Setting' is 15 lbf/in² (1.05 bar) and the 'Suction Strainer' is 0.005 inch (125 microns).
How will I receive this Service Manual?
This is a 587-page searchable PDF ready for immediate download. Works on any device, so pull it up on your phone while you're under the hood. No shipping, no waiting.
Are there any print restrictions on this manual?
Yes, print as many copies as you want, and there are no restrictions. Many mechanics print the section they need and bring it to the shop floor.
Can I find wiring schematics in this JCB 504B, 526, Loadall manual?
Yes, this JCB 504B, 526, Loadall Service Manual includes complete electrical wiring diagrams, wire routing, and connector pinouts.
Document Quality
This document is a scanned PDF with an OCR text layer, allowing you to search and copy text throughout. The text quality is consistently crisp and easy to read on all pages. Diagrams and illustrations are raster images; while most labels are readable, some text within the diagrams on pages 24 and 25 is blurry or pixelated. Pages are generally clean with no significant scan artifacts, stains, or skewed content, though there are a few blank pages (e.g., page 36, 45, 208, 218, 220, 222, 224, 226, 228, 230, 232, 283, 284
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