JCB 3CX / 4CX

This article brings together the drawings and parts lists for the PD70 rear axle of the JCB 3CX backhoe loader from the JCB parts catalogue: the complete axle, the axle arm with hub reduction and brake plates, the drive head with brake pistons, the differential and the remote breather. The example is axle 450/44530 with a 15.78:1 ratio and limited slip differential, fitted to 3CX-T machines with front wheel steering (catalogue 9812/0010, serial numbers 00960000–00989999, 01297000–01297999, 01327000–01349999, 01616000–01621599, 01705500–01709999). Part numbers shown as links open the product pages in our catalogue.

On JCB 3CX and 4CX backhoe loaders with the JCB Dieselmax engine the cooling system consists of a cooler pack (engine radiator plus the hydraulic and transmission oil cooler), a fan with a viscous coupling (or a direct drive fan), an expansion tank and the hoses. System capacity is 18.5 litres. Below are the assembly drawings with JCB part numbers from the JCB parts catalogue for 3CX-T machines with Tier 2 engines (catalogue 9812/0010, serial numbers 00960000–00989999, 01297000–01297999, 01327000–01349999, 01616000–01621599, 01705500–01709999), together with maintenance data from the service manual.

Section C of the JCB service manual (publication 9803/3290-15) gives the JCB 3CX and 4CX backhoe loader wiring diagram in two versions: one for machines built up to May 2009 with analogue instruments and one for machines from May 2009 with the digital instrument panel. On the earlier machines the main machine circuit takes two sheets, with separate circuits for the gearboxes and options; the later circuit runs to 15 sheets. Below are the main sheets, the component keys and a guide to reading wire numbers.

There is no single hydraulic circuit for the JCB 3CX and 4CX backhoe loader: it depends on the build year and the pump type. Section E of the JCB service manual (publication 9803/3290-14) gives separate circuits for the gear pump 3CX built before and after September 2007, for the variable flow 4CX (7-spool and 6-spool), and for the 3C-14 (214e) and 3C machines. Below you will find the circuits themselves, the component keys and some notes on tracing the oil flow through a circuit.

Sections 1 “General Information” and 2 “Care and Safety” open the JCB service manual for the 3C, 3CX and 4CX backhoe loaders (issue 9803/3290-16). They explain how to identify the machine and its major units from the data plates and serial numbers, which fuels may be used, what torque to apply to bolts and hydraulic connections, and which sealants and thread-locking compounds to use, and they set out the general safety rules for operation and servicing. The PDF runs to 44 pages.

Section D of the JCB service manual (publication 9803/3290-14) deals with the controls of JCB 3C, 3CX and 4CX backhoe loaders with mechanical lever controls: the steering column and column switches, the control rods and linkages for the loader valve and excavator valve, the auxiliary footpedal, the heater, boom lock, throttle and park brake cables, and adjustment of the shovel reset (return to dig). The PDF runs to 32 pages.

Section A of the JCB service manual (publication 9803/3290-14) covers the attachment hydraulics of JCB 3C, 3CX and 4CX backhoe loaders: the high flow hammer circuit, the hydraulic tool circuit (HTC) for hand-held tools, connecting hoses and quick release couplings, the return line filter and the 3 point hitch on 214e Landscaper machines. The PDF has 44 pages.

Section B of the JCB service manual (publication 9803/3290-15) covers the body and framework of JCB 3C, 3CX and 4CX backhoe loaders: the cab air conditioning and heater, the cab itself and bonded glazing, the fuel and hydraulic tanks, the loader arms, stabiliser legs, excavator boom and dipper, the kingpost and sideshift carriage, plus the stabiliser leg alarm and boom overload warning. The PDF has 150 pages.

Section L of the JCB service manual (publication 9803/3290-15) is dedicated to JCB 3CX and 4CX machines with joystick (servo) controls. It describes only what sets these machines apart from lever-controlled ones: the joysticks, the servo isolation valve, the proportional solenoid valves and the thumbwheel control unit, the load sensing system with pressure compensators, unloader valves, pumps and sectional valve blocks. The section also contains fuses and relays, electrical and hydraulic circuits, fault finding tables, pressure tests and component overhaul procedures. The PDF has 354 pages.

Section C of the JCB service manual (publication 9803/3290-15) covers the electrical system of JCB 3C, 3CX and 4CX backhoe loaders: fuses and relays, circuit diagrams for machines of different build years, battery, alternator and starter motor testing, the wire numbering system, harness repair, earth points and harness drawings. The PDF has 402 pages, most of them harness drawings.

Section K of the JCB service manual (publication 9803/3290-14) deals with the installation of the JCB Dieselmax engine in JCB 3C, 3CX and 4CX backhoe loaders. It gives the technical data for each engine build, the cold start heater electrics with their fault codes and the operation of the viscous fan coupling, together with the removal procedures for the radiator, expansion tank, fuel injection pump and the engine itself. The PDF runs to 30 pages.

Section H of the JCB service manual (publication 9803/3290-14) covers the steering of the JCB 3C, 3CX and 4CX backhoe loaders: the hydraulic steer unit, priority valve, steering rams on the axles and the steer mode valve on four wheel steer machines. It includes technical data, hydraulic schematics, operation, fault finding tables, pressure tests, bleeding and component overhaul procedures. The PDF runs to 82 pages.

Section F of the JCB service manual covers the transmission of the JCB 3C, 3CX and 4CX backhoe loaders: Synchro Shuttle SS700, Powershift PS764 and PS766 gearboxes, torque converter, front and rear axles, propshafts and oil cooler. It contains technical data, gearbox operation and electrics, pressure tests, the torque converter stall test, fault finding tables and removal procedures. This is issue 9803/3290-16 of the manual; the PDF runs to 306 pages.

Section G of the JCB service manual (publication 9803/3290-14) covers the braking system of the JCB 3C, 3CX and 4CX backhoe loaders: service and park brakes, compensating master cylinders, 2 and 4 wheel braking modes, fault finding, bleeding, tests and adjustments. The section PDF runs to 78 pages.

Section E of the JCB service manual (publication 9803/3290-14) deals with the hydraulic system of the JCB 3C, 3CX and 4CX backhoe loaders. It brings together technical data for the pumps and valve blocks, hydraulic circuits for machines of different build years, valve operation, fault finding tables, and the procedures for pressure testing and for overhauling the pump, valves and rams. The section PDF runs to 302 pages.

The diagram below shows where the pins and bushes are fitted on the JCB 3CX backhoe loader, with every item numbered and linked to a specific assembly on the machine.

This page covers the routine maintenance section for the JCB 3CX / 4CX backhoe loader: service intervals by hour meter reading, pre-shift checks, lubrication points, fluids and capacities, and the standard procedures for each system — engine, fuel, hydraulics, transmission, axles, brakes and electrics.