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Jcb G55Q
Maintenance schedule, common problems & OEM parts breakdown
The JCB G55Q is a compact crawler excavator engineered for utility trenching and confined-space earthmoving. The machine utilizes a JCB Dieselmax or EcoMAX engine family depending on the specific production series and regional emissions configuration. Operating weight ranges vary by configuration, counterweight setup, and track shoe width, typically falling within the 5.5 to 6.5 metric ton class. Production years span multiple generations of the JS-series compact excavator line, with the G55Q serving as a specific model designation within that broader family. Configurations offered include standard reach and long reach booms, varying stick lengths, and options for auxiliary hydraulics and quick couplers.
Across the JS-series generations, the G55Q evolved through updates to the engine cooling architecture, hydraulic pump efficiency, and cab ergonomics to meet tightening emissions standards. The machine remains significant in the used and parts market due to its modular powertrain design and the widespread availability of JCB Dieselmax components. Its compact tail swing and ground-level service access points make it a high-demand asset for municipal and utility contractors.
Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.
Jcb G55Q specifications
Engine
| Model | Perkins 404D-22 |
| Net Power | 35.7 kW (48 hp) |
| Gross Power | 35.7 kW (48 hp) |
| Displacement | 4.4 L (4399 cc) |
| Cylinders | 4 |
| Emissions Tier | Tier 4 Final / EU Stage V |
Weights
| Operating Weight | 4946 kg (10,654 lb) / 5266 kg (11,610 lb) / 5520 kg (12,169 lb) |
| Shipping Weight | Not documented for this exact serial range — verify with your dealer |
| Ground Pressure | Not documented for this exact serial range — verify with your dealer |
Dimensions
| Transport Length | 5.518 m (18 ft 1 in) |
| Transport Width | 1.95 m (6 ft 5 in) |
| Transport Height | 2.55 m (8 ft 4 in) |
| Track Gauge | 400 mm (15.7 in) |
| Ground Clearance | Not documented for this exact serial range — verify with your dealer |
Performance
| Travel Speed | Not documented for this exact serial range — verify with your dealer |
| Digging Depth | 3.84 m (12 ft 7 in) |
| Digging Reach | 6.2 m (20 ft 4 in) |
| Gradeability | Not documented for this exact serial range — verify with your dealer |
Service capacities (summary)
| Fuel Tank | Not documented for this exact serial range — verify with your dealer |
| Hydraulic System | Not documented for this exact serial range — verify with your dealer |
| Engine Oil | Not documented for this exact serial range — verify with your dealer |
| Cooling System | Not documented for this exact serial range — verify with your dealer |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
Jcb G55Q maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
Servicing the G55Q beyond the schedule
Predictive Maintenance & Fluid Analysis
Baseline oil sampling at the 500-hour interval is critical for the JCB G55Q. Collect samples from the engine, hydraulic tank, front axle, and final drives simultaneously. Compare subsequent 500-hour samples against this baseline to detect developing bearing wear or hydraulic contamination early. The JCB Dieselmax and EcoMAX engines rely on strict fuel filtration; monitor fuel filter restriction indicators closely. Hydraulic return filter inspection for metallic debris at every 500-hour service provides early warning of pump or valve degradation before catastrophic failure occurs.
Corrective & Common Repairs
Common repairs on the G55Q focus on the undercarriage and hydraulic seals. Inspect track tension regularly; incorrect tension accelerates roller and idler wear. Check kingpost and boom pivot pins for elongation, which causes binding in hydraulic cylinders. Address hydraulic hose chafing at the boom base and stick joints immediately to prevent high-pressure line failure. Turbocharger boot condition and wastegate function require inspection during the 1000-hour service to maintain engine performance and prevent excessive soot accumulation in the cooling system.
Overhaul & Rebuild Points
The 2000-hour deep service dictates major overhaul timing. Measure swing ring radial and axial play using dial indicators on tracked models to determine slewing bearing health. Inspect structural welds on the boom, arm, and chassis side frames for cracking or unauthorized repair attempts. Evaluate brake disc wear and immersed brake condition on wheeled variants. Injector spray patterns must be checked via diagnostic tool; replace injectors showing poor atomization to restore fuel efficiency and prevent carbon buildup in the combustion chamber.
Seasonal & Environment Servicing
In cold climates, verify coolant mixture strength and heater core operation before winter. Ensure DEF systems (if fitted) are protected from freezing. In dusty environments, inspect air filter restriction indicators more frequently than the standard schedule and clean the radiator cooler fins daily to prevent overheating. Store the machine under cover to protect the cab HVAC evaporator and electrical connections from moisture.
G55Q common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 32/925705 | Element, Fuel Sediment/Water, 150 Microns | Fuel system service | Check fitment → |
| 320/04114 | Retainer, Fuel Filter | Fuel system service | Check fitment → |
| 320/07155 | Filter, Fuel - 5 Micron, Self Colour Can | Fuel system service | Check fitment → |
| 32/925694 | Element, Fuel Filter | Fuel system service | Check fitment → |
| 32/925717 | Filter, Fuel Sediment, 30 Micron | Fuel system service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
G55Q fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| P0087 | Fuel rail/system pressure too low | Clogged fuel filters or failing fuel lift pump | Check fuel filter condition and fuel pump operation |
| P0117 | Engine coolant temperature sensor circuit low voltage | Faulty coolant temperature sensor or wiring issue | Inspect sensor wiring and test sensor resistance |
| P0521 | Engine oil pressure sensor range/performance issue | Faulty oil pressure sensor or low oil level | Check oil level and test sensor signal |
| P2047 | DEF/AdBlue injector circuit open (SCR system fault) | Open circuit in reductant injector wiring | Inspect injector connector and wiring harness |
| U0100 | Lost communication with Engine Control Module (ECM) | CAN bus communication failure or loose connection | Check battery voltage and CAN bus connections |
| 101 | Low transmission clutch pressure detected | Transmission hydraulic pressure loss | Check transmission fluid level and pressure |
| F01 | Engine control module failure | ECU hardware or connection fault | Check ECU connections and power supply |
| E420 | Low hydraulic pressure | Hydraulic pump or system leak | Refill hydraulic fluid and check for leaks |
| E512 | Low voltage detected | Battery or charging system issue | Charge or replace battery and check alternator |
| D901 | Communication error with display unit | CAN bus wiring fault to display | Inspect CAN bus wiring to display module |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
G55Q attachments & work tools
Generator Set
The G55Q is a generator set model, grouped with the G50R, G80R, G55X, G66X, G88X, G110X, and G120X series in the Operator’s Manual (Part No. EN - the OEM part reference - Issue 2 - May 2008). This designation identifies the machine as power generation equipment rather than a construction carrier, meaning standard earthmoving or lifting attachments are not applicable.
Engine
The G55Q utilizes a JCB DieselMax engine, which is a 4.4L, 4-cylinder diesel unit. The engine delivers a maximum power output of 55kW (74hp) at 2200rpm. The engine serial number is a 17-digit code stamped on the cylinder block, distinct from the machine PIN.
Hydraulic System
The total hydraulic system capacity varies by configuration and series depending on the specific equipment fitted. The system requires JCB genuine hydraulic oil featuring high-quality base oils and additive technology to ensure maximum component life and warranty protection.
Fluids and Lubricants
Recommended fluids include JCB branded engine oil, coolant, and transmission fluids. For the first 100 hours of operation with a new or reconditioned engine, JCB 10W/30 multigrade oil is required before switching to the standard recommended lubricant. Coolant mixtures with 55% antifreeze provide freeze protection down to -36°C (-33°F).
Safety and Security
The machine incorporates a JCB immobilizer system using a unique key or keypad. It features a steel case work battery disconnect switch and meets ROPS & TOPS safety standards.
All G55Q assemblies by section
Every catalogued assembly group for the Jcb G55Q. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Z Electrical Power Generation, Unit
Z0-3-1 Generator Set, G55q 50kva, 50hz 380/415v Prime
| 32***20 | Jcb, Generator G55q, 50kva | 1 |
Z0-4-1 Generator Set, G63 60kva, 50hz 380/415v Prime
| 32***21 | Jcb, Generator G63, 60kva | 1 |
Z0-6-1 Generator Set, G80r 80kva, 50hz 380/415v Prime
| 32***23 | Jcb, Generator G80r, 80kva | 1 |
Z0-1-1 Generator Set, G50r 50kva, 50hz 380/415v Prime
| 32***18 | Jcb, Generator G50r, 50kva | 1 |
Z0-8-1 Generator Set, G88q 80kva, 50hz 380/415v Prime
| 32***25 | Jcb, Generator G88q, 80kva | 1 |
Z0-5-1 Generator Set, G63q 60kva, 50hz 380/415v Prime
| 32***22 | Jcb, Generator G63q, 60kva | 1 |
Z0-7-1 Generator Set, G88 80kva, 50hz 380/415v Prime
| 32***24 | Jcb, Generator G88q, 80kva | 1 |
Z0-2-1 Generator Set, G55 50kva, 50hz 380/415v Prime
| 32***19 | Jcb, Generator G55, 50kva | 1 |
Z1-2-1 Engine, Complete, 320/50015
| 32***60 | G.A, Power Take-Off Blanking Plate, Sae | 1 |
| 32***20 | Fan, Idler Bracket, No Aircon 1.16+1.25 | 1 |
| 32***23 | G.A, Engine Dipstick | 1 |
Z1-1-1 Engine, Complete, 320/50014
| 32***60 | G.A, Power Take-Off Blanking Plate, Sae | 1 |
| 32***20 | Fan, Idler Bracket, No Aircon 1.16+1.25 | 1 |
| 32***23 | G.A, Engine Dipstick | 1 |
Z2-2-1 Sealant Templates
| 89***49 | Template, Oil Pan Sealant | 1 |
| 89***75 | Template, Sealant, Bedplate To Block | 1 |
| 89***77 | Template, Sealant, Flywheel, Housing To Gearcase | 1 |
Z2-1-1 Service Tools
| 32***20 | Bracket, Engine Lifting | 1 |
| 89***46 | Tool, Fitting, Core Plug | 1 |
| 89***47 | Tool, Crankshaft Turning | 1 |
Z3-1-1 Lubricants Primers, & Sealants
| 32***28 | Sealant, 620 | 0 |
| 32***29 | Lubricant, O Ring, P80 | 0 |
| 32***30 | Sealant, 5900 | 0 |
Z4-3-1 Gasket Set, Bottom Overhaul
| 32***31 | Sealant, 518 | 1 |
| 32***29 | Seal, Rear Oil | 1 |
| 32***19 | Seal, Front Oil | 1 |
Z4-5-1 Gasket Set, Top Overhaul, Tc
| 32***08 | Gasket, Cylinder Head | 1 |
| 32***33 | Seal, Valve Stem | 16 |
| 32***40 | O Ring | 2 |
Z4-2-1 Gasket Set, Top Overhaul
| 32***08 | Gasket, Cylinder Head | 1 |
| 32***33 | Seal, Valve Stem | 16 |
| 32***40 | O Ring | 1 |
Z4-1-1 Seal Kit, Rocker Cover
| 32***92 | O Ring, Oil Filler Cap | 1 |
| 32***87 | Cap, Fuel Injector | 4 |
| 32***88 | Cap, Fuel Pipe | 8 |
Z4-4-1 Seal Kit, Oil Pan
| 32***30 | Sealant, 5900 | 1 |
| 32***50 | O Ring | 2 |
| 32***62 | Seal, Oil-Pick-Up | 1 |
Z5-6-3 Kit-Engine Overhaul, Oversize - 1.00mm, Tc
| 32***40 | Bolt, Con-Rod, M8 X 57 | 8 |
| 32***17 | Kit-Top Gasket, Turbo Engine | 1 |
| 32***18 | Kit-Bottom Gasket | 1 |
Z5-6-2 Kit-Engine Overhaul, Oversize - 0.50mm, Tc
| 32***40 | Bolt, Con-Rod, M8 X 57 | 8 |
| 32***17 | Kit-Top Gasket, Turbo Engine | 1 |
| 32***18 | Kit-Bottom Gasket | 1 |
Z5-6-1 Kit-Engine Overhaul, Standard, Tc
| 32***40 | Bolt, Con-Rod, M8 X 57 | 8 |
| 32***11 | Kit-Piston, Standard, Turbo | 4 |
| 32***17 | Kit-Top Gasket, Turbo Engine | 1 |
Z5-4-1 Engine, Long, Tc 320/40081
| 32***32 | Gear, Crankshaft, Assembly | 1 |
| 32***43 | Kit-Gasket, Long Engine, Tc/Tca | 1 |
| 32***03 | Piston, & Con-Rod, Assembly | 1 |
Z5-3-1 Engine, Long, 320/40061
| 32***32 | Gear, Crankshaft, Assembly | 1 |
| 32***42 | Kit-Gasket, Long Engine, Nat/Asp | 1 |
| 32***05 | Camshaft, Assembly | 1 |
Z5-1-1 Engine, Short, 320/40059
| 32***29 | Seal, Rear Oil | 1 |
| 32***19 | Seal, Front Oil | 1 |
| 32***16 | Kit-Top Gasket, Naturally Aspirated | 1 |
Z5-2-1 Engine, Short, Tc 320/40060
| 32***29 | Seal, Rear Oil | 1 |
| 32***19 | Seal, Front Oil | 1 |
| 32***17 | Kit-Top Gasket, Turbo Engine | 1 |
Z5-5-3 Kit-Engine Overhaul, Oversize - 1.00mm
| 32***40 | Bolt, Con-Rod, M8 X 57 | 8 |
| 32***16 | Kit-Top Gasket, Naturally Aspirated | 1 |
| 32***18 | Kit-Bottom Gasket | 1 |
Z5-5-1 Kit-Engine Overhaul, Standard
| 32***40 | Bolt, Con-Rod, M8 X 57 | 8 |
| 32***10 | Kit-Piston, Standard, Naturally Aspirated | 4 |
| 32***16 | Kit-Top Gasket, Naturally Aspirated | 1 |
Z5-5-2 Kit-Engine Overhaul, Oversize - 0.50mm
| 32***40 | Bolt, Con-Rod, M8 X 57 | 8 |
| 32***16 | Kit-Top Gasket, Naturally Aspirated | 1 |
| 32***18 | Kit-Bottom Gasket | 1 |
Z6-4-1 Primary Fuel Filter, Element, Cold Climate
| 32***05 | Element, Fuel Sediment/Water, 150 Microns | 1 |
| 32***33 | Seal, O'Ring | 1 |
Z6-1-1 Fuel Filter
| 13***5Z | Bolt, Flange Head, M8 X 20 Lg | 1 |
| 21***07 | Pin, Tension | 1 |
| 32***14 | Retainer, Fuel Filter | 1 |
Z6-3-1 Primary Fuel Filter
| 13***7Z | Screw, M8 X 25 | 2 |
| 13***7Z | Screw, M12 X 25 | 2 |
| 32***94 | Element, Fuel Filter | 1 |
Z6-2-1 Oil Filter
| 32***33 | Filter, Engine Oil | 1 |
| 32***23 | G.A, Oil Cooler 60kw, Inc Filter/Filler | 1 |
| 32***24 | Cooler, Oil, Inc Filter/Filler | 1 |
Z8-3-2 Lower Idler Pulley
| 13***5Z | Bolt, Flange Head, M8 X 65 | 3 |
| 22***62 | Circlip, Internal | 1 |
| 32***22 | Pulley, Idler, D=124mm | 1 |
Z8-1-1 Crankshaft Pulley
| 32***69 | Bolt, Torx Head Flange, M12 X 65 X 12.9 | 3 |
| 32***43 | Pulley, Crankshaft | 1 |
| 32***01 | Crankshaft, Assembly | 1 |
Z8-2-1 Autotensioner, Drive Belt
| 13***8Z | Screw, Star Drive, M8 X 30 | 3 |
| 32***84 | Adjuster, Auto-Tension | 1 |
| 32***46 | Adjuster, Autotensioner | 1 |
Z8-12-3 Front End Drive, Accessory, With Cooling Fan
| 32***00 | Hub, Fan Drive, Assembly | 1 |
| 32***03 | Pulley, Cooling Fan 1.25:1, D=133mm | 1 |
| 32***30 | Pulley, Idler, Long | 1 |
Z9-1-1 Starter Motor, 12.Volt
| 13***8Z | Screw, Star Drive, M10 X 30 | 3 |
| 32***32 | Motor, Starter 12v, With Earth Stud | 1 |
| 32***52 | Motor, Starter | 1 |
Z10-1-1 Alternator, 12volt - 95amp
| 13***8Z | Screw, Star Drive, M10 X 30 | 1 |
| 13***2Z | Bolt, Star Drive, M10 X 120 | 1 |
| 32***60 | Alternator, 12v-95amp | 1 |
Z11-1-1 Switches & Senders, 12volt
| 17***02 | Seal, Ring | 1 |
| 32***46 | Switch, Oil Pressure | 1 |
| 32***57 | Seal, Bonded | 1 |
Z12-2-1 Fuel Pipework, Low Pressure
| 32***39 | Bolt, Banjo M12 | 2 |
| 32***71 | G.A, Ga Fuel Pipes(Hp/Lp), Genset | 1 |
| 32***33 | Ring, Snap | 1 |
Z12-3-1 Fuel Pipework, Primary Filter
| 32***41 | Pipe, Fuel Filter To Pump | 1 |
| 32***42 | Clip, Pipe, 8/9mm Dia | 1 |
| 32***43 | Clip, Pipe, 9.5/10mm Dia | 1 |
Z12-1-1 Fuel Pipework, High Pressure
| 32***11 | Clip, F.I.P 2 Way | 4 |
| 32***59 | Pipe, Fuel, Injector 1 & 2, Assembly | 1 |
| 32***60 | Pipe, Fuel Injector 3 & 4, Assembly | 1 |
Z13-1-1 Fuel Injector
| 32***93 | Bolt, Injector Clamp | 4 |
| 32***39 | Clamp, Fuel Injector | 4 |
| 32***24 | Seal, Injector | 1 |
Z13-2-1 Fuel Injector, Tc
| 32***93 | Bolt, Injector Clamp | 4 |
| 32***39 | Clamp, Fuel Injector | 4 |
| 32***24 | Seal, Injector | 1 |
Z14-1-1 Fuel Lift Pump
| 13***7Z | Screw, Star Drive, M8 X 25 | 3 |
| 32***40 | Pump, Fuel Lift | 1 |
| 32***51 | O Ring | 1 |
Z15-1-1 Fuel Injection Pump, 12v - 55kw
| 32***19 | Seal, Injection Pump To Timing Case | 1 |
| 32***64 | Nut, M8 Flange Head | 3 |
| 32***77 | Nut, M14, Fuel Injection Pump Gear | 1 |
Z15-4-1 Fuel Injection Pump, 12v - 89kw
| 32***19 | Seal, Injection Pump To Timing Case | 1 |
| 32***64 | Nut, M8 Flange Head | 3 |
| 32***77 | Nut, M14, Fuel Injection Pump Gear | 1 |
Z15-50-1 Injection Pump, Service Parts
| 32***74 | Kit-Regulator | 1 |
| 32***75 | Kit-Timing Window | 1 |
| 32***76 | Kit-Plug | 1 |
Z15-2-1 Fuel Injection Pump, 12v - 86kw
| 32***19 | Seal, Injection Pump To Timing Case | 1 |
| 32***64 | Nut, M8 Flange Head | 3 |
| 32***77 | Nut, M14, Fuel Injection Pump Gear | 1 |
Z16-1-1 Water Pump
| 32***10 | Gasket, Water Pump | 1 |
| 32***14 | Screw, Pan Head, M8 X 25 | 4 |
| 32***42 | Pump, Water, Assembly | 1 |
Z17-1-1 Water Inlet, Connector
| 13***7Z | Screw, Star Drive, M8 X 25 | 4 |
| 32***01 | Gasket, Water Inlet Pipe | 1 |
| 32***47 | Connector, Water Inlet, Assembly | 1 |
Z18-1-1 Thermostat & Housing
| 13***5Z | Screw, Star Drive, M8 X 20 | 3 |
| 32***40 | Housing, Thermostat | 1 |
| 32***43 | Seal, C | 1 |
Z19-11-1 Cover, Injector Seal
| 32***16 | Cover, Injector Seal | 1 |
| 32***17 | Insert, Injector Seal Cover | 4 |
| 32***21 | G.A, Cover.Injector Seal | 1 |
Z19-1-1 Rocker Cover
| 32***90 | Cap, Oil Filler, Assembly | 1 |
| 32***92 | O Ring, Oil Filler Cap | 1 |
| 32***73 | Spring, Ccv Valve | 1 |
Z20-1-1 Rocker Shaft, Assembly
| 13***6Z | Bolt, M8 X 70 | 1 |
| 32***23 | Washer, Spring | 4 |
| 32***02 | Bolt, M8 X 55 | 7 |
Z20-2-1 Rocker Shaft, Assembly
| 13***6Z | Screw, Star Drive, M8 X 70 | 1 |
| 32***23 | Washer, Spring | 4 |
| 32***02 | Bolt, M8 X 55 | 7 |
Z20-3-1 Rocker Shaft, Assembly
| 13***2Z | Bolt, M8 X 50 | 7 |
| 13***5Z | Bolt, Flange Head, M8 X 65 | 1 |
| 32***23 | Washer, Spring | 4 |
Z21-1-1 Valve Tappets & Push, -Rods
| 32***15 | Rod, Push | 8 |
| 32***24 | Tappet, Valve | 8 |
| 32***05 | Camshaft, Assembly | 1 |
Z21-2-1 Pushrods & Tappets
| 32***24 | Tappet, Valve | 8 |
| 32***77 | Rod, Push | 8 |
Z22-1-1 Turbocharger, Tc
| 32***07 | Stud, M8 X 75 | 4 |
| 32***08 | Nut, Lock, M8 Special | 4 |
| 32***53 | Gasket, Single, Tc To Manifold | 1 |
Z23-2-1 Turbo Crossover Tube
| 32***14 | G.A, Turbo Crossover Tube, Garrett Htt | 1 |
| 32***33 | Tube, Turbo Crossover | 1 |
| 32***36 | Hose, 49.5mm X 55mm | 2 |
Z23-1-1 Turbo Pipework
| 13***3Z | Screw, M6x16 | 2 |
| 13***5Z | Screw, Star Drive, M8 X 20 | 2 |
| 32***51 | O Ring | 2 |
Z25-4-1 Induction Manifold, Tc
| 13***7Z | Screw, Star Drive, M8 X 25 | 10 |
| 32***11 | Plate, Blanking, Intake Heater | 1 |
| 32***12 | Gasket, Intake Heater | 1 |
Z25-2-1 Induction Manifold, Tc
| 13***7Z | Screw, Star Drive, M8 X 25 | 10 |
| 32***11 | Plate, Blanking, Intake Heater | 1 |
| 32***12 | Gasket, Intake Heater | 1 |
Z25-1-1 Induction Manifold
| 13***7Z | Screw, Star Drive, M8 X 25 | 10 |
| 32***11 | Plate, Blanking, Intake Heater | 1 |
| 32***12 | Gasket, Intake Heater | 1 |
Z26-1-1 Exhaust Manifold
| 32***04 | Gasket, Exhaust Manifold | 1 |
| 32***20 | Manifold, Exhaust | 1 |
| 32***45 | Bolt, M10 X 57 | 8 |
Z26-2-1 Exhaust Manifold, Tc
| 32***00 | Manifold, Exhaust | 1 |
| 32***45 | Bolt, M10 X 57 | 8 |
| 32***80 | Gasket, Exhaust Manifold | 1 |
Z27-3-1 Cylinder Head, Assembly
| 14***15 | Washer, Seal; Replaces Khj0891 | 1 |
| 32***03 | Plug, Core, D=40mm | 2 |
| 32***28 | Sealant, 620 | 0 |
Z28-1-1 Brackets, Engine Lifting
| 13***8Z | Screw, Star Drive, M10 X 30 | 4 |
| 32***20 | Bracket, Engine Lifting | 2 |
| 32***39 | Label, Front Lifting Eye | 1 |
Z29-1-1 Oil Cooler
| 13***5Z | Bolt, Flange Head, M8 X 20 Lg | 5 |
| 13***7Z | Screw, Star Drive, M8 X 25 | 11 |
| 21***07 | Pin, Tension | 1 |
Z30-1-1 Oil Level Dipstick, & Tube, Standard
| 13***5Z | Bolt, Flange Head, M8 X 20 Lg | 1 |
| 32***27 | O Ring | 2 |
| 32***29 | O Ring | 1 |
Z31-1-1 Oil Sump
| 13***3Z | Screw, Star Drive, M8 X 16 | 2 |
| 32***13 | Plug, Oil Drain | 2 |
| 32***50 | O Ring | 2 |
Z32-1-1 Oil Pump
| 13***2Z | Screw, Star Drive, M8 X 50 | 4 |
| 32***31 | Pump, Engine Oil | 1 |
| 32***20 | Pump, Oil | 1 |
Z33-1-1 Flywheel Assembly, 11.5"Sae J620
| 32***42 | Bolt, M14 X 108mm | 1 |
| 32***72 | Flywheel, Assembly | 1 |
| 32***74 | Bolt, M14 X 100 Special | 8 |
Z34-1-1 Flywheel Housing, Fh1
| 13***3Z | Screw, Star Drive, M8 X 16 | 2 |
| 13***7Z | Screw, Star Drive, M8 X 25 | 4 |
| 13***2Z | Screw, Star Drive, M8 X 50 | 8 |
Z35-1-1 Camshaft, & Idler Gear
| 32***29 | Camshaft, Assembly, Na | 1 |
| 32***15 | Hub, Idler Gear | 1 |
| 32***17 | Bolt, Pan Head, M10 X 60mm | 3 |
Z35-2-1 Camshaft, & Idler Gear, Tc
| 32***30 | Camshaft, Assembly, Tc/Tca | 1 |
| 32***15 | Hub, Idler Gear | 1 |
| 32***17 | Bolt, Pan Head, M10 X 60mm | 3 |
Z36-1-1 Timing Case & Covers, Idler Blanking
| 13***7Z | Screw, Star Drive, M10 X 25 | 2 |
| 13***9Z | Screw, Star Drive, M12 X 35 | 2 |
| 32***25 | Sealant, Loctite 5182 | 0 |
Z37-1-1 Piston & Con-Rod, Assemblies
| 32***17 | Bush, Small End | 1 |
| 32***40 | Bolt, Con-Rod, M8 X 57 | 2 |
| 32***50 | Circlip | 2 |
Z37-2-1 Piston & Con-Rod, Assemblies, Tc
| 32***17 | Bush, Small End | 1 |
| 32***40 | Bolt, Con-Rod, M8 X 57 | 2 |
| 32***50 | Circlip | 2 |
Z38-1-1 Crankshaft Assembly
| 13***1Z | Screw, Star Drive, M10 X 45 | 1 |
| 21***05 | Dowel, Pin | 2 |
| 32***19 | Seal, Front Oil | 1 |
Z39-1-1 Cylinder Block, Assembly
| 13***5Z | Screw, Star Drive, M8 X 20 | 2 |
| 13***8Z | Bolt, Star Drive, M8 X 80 | 16 |
| 32***01 | Plug, Core, D=25mm | 1 |
Z39-2-1 Cylinder Block, Assembly, Tc
| 13***8Z | Bolt, Star Drive, M8 X 80 | 16 |
| 32***01 | Plug, Core, D=25mm | 1 |
| 32***02 | Plug, Core, D=36mm | 2 |
Z43-1-1 Air Filter, Installation
| 13***9Z | Setscrew, M8x35 | 2 |
| 13***7Z | Screw, M10 X 25 | 3 |
| 16***77 | Cap, Rain | 1 |
Z45-11-1 Exhaust System, Canopy Build, Nat/Aspirated
| 02***16 | Nut | 4 |
| 13***5D | Setscrew, M10 X 20 | 4 |
| 14***8D | Washer, M10 | 4 |
Z45-2-1 Exhaust Silencer, Open Build, Turbo
| 02***35 | Nut, Anti-Seize | 4 |
| 32***97 | Silencer, Exhaust | 1 |
| 32***53 | Clamp, "U" | 1 |
Z45-12-1 Exhaust System, Canopy Build, Turbo
| 02***35 | Nut, Anti-Seize | 3 |
| 13***5D | Setscrew, M10 X 20 | 4 |
| 14***8D | Washer, M10 | 4 |
Z45-1-1 Exhaust Silencer, Open Build, Nat/Aspirated
| 02***16 | Nut | 4 |
| 32***06 | Gasket | 1 |
| 32***63 | Stud, M8 X 1.25 | 4 |
Z46-11-1 Fan Guards
| 13***3D | Setscrew | 24 |
| 14***6D | Washer, M6 Plain | 24 |
| 14***6D | Washer, Spring, M6 | 24 |
Z46-2-1 Radiator & Fittings
| 30***54 | Radiator, Assembly | 1 |
| 30***55 | Cap, Radiator Pressure | 1 |
Z46-1-1 Radiator & Fittings, Naturally Aspirated
| 30***53 | Radiator, Assembly | 1 |
| 30***55 | Cap, Radiator Pressure | 1 |
Z48-11-1 Radiator, Coolant Drain
| 32***70 | Valve, 1/2"Bsp Female, 1/2"Bsp Male | 1 |
| 32***71 | Adapter, 1/2"Bsp M 1/2"Tail | 2 |
| 32***72 | Hose, Fuel 1/2"Bore | 1 |
Z48-1-1 Radiator, Hose & Pipework
| 30***58 | Clip, Hose | 4 |
| 83***74 | Hose, Top Radiator | 1 |
| 83***75 | Hose, Bottom Radiator | 1 |
Z49-1-1 Cooling Fan & Spacer
| 13***8D | Bolt | 4 |
| 14***7D | Washer, M8 Plain | 4 |
| 14***7D | Washer, M8 Spring | 4 |
Z50-1-1 Fuel Pipes, Fuel Tank To Filter
| 32***16 | Hose, Fuel Supply | 2 |
| 32***68 | Clip, 6mm Hose | 4 |
| 32***74 | Adapter, 3/8" Male 3/8"Male | 2 |
Z51-11-1 Filter, Fuel Sedimenter, (Racor)
| 32***09 | Filter, Fuel, Assembly | 1 |
| 32***10 | Element, Fuel Filter | 1 |
| 32***41 | O Ring | 1 |
Z57-1-1 Engine Oil Drain
| 14***19 | Seal, Dowty | 1 |
| 22***03 | Clip, Jubilee | 2 |
| 32***71 | Adapter, 1/2"Bsp M 1/2"Tail | 2 |
Z60-2-1 Base & Fittings
| 13***8D | Setscrew, M10 X 30 | 0 |
| 13***8D | Setscrew, M12 X 30 | 0 |
| 13***3D | Nut, Self Lock M10 | 0 |
Z60-11-1 Fuel Tank
| 32***18 | Cap, Fuel Tank | 1 |
| 32***10 | Tank, Fuel | 1 |
| 32***64 | Plug, Male 3/8"Bsp, Socket Head | 1 |
Z60-5-1 Lifting Bracket, (Optional)
| 13***2D | Setscrew, M16 X 50mm | 8 |
| 13***3Z | Nut | 8 |
| 14***1D | Washer, M16 | 16 |
Z60-1-1 Base & Fittings
| 13***8D | Setscrew, M10 X 30 | 0 |
| 13***8D | Setscrew, M12 X 30 | 0 |
| 13***3D | Nut, Self Lock M10 | 0 |
Z61-21-1 Canopy Soundproofing
| 32***14 | Kit-Panel, Foam Foil Backed, Centre Section | 1 |
| 32***15 | Kit-Panel, Foam Soundproofing, Centre Section | 1 |
| 32***39 | Kit-Panel, Soundproofing, End Cap Sections | 1 |
Z61-1-1 Canopy Assembly
| 13***5D | Setscrew, M8x20 | 74 |
| 13***3D | Nut, Self Lock M8 | 22 |
| 14***7D | Washer, M8 Plain | 74 |
Z62-1-1 Alternator, Uci 224d-16
| 32***08 | Regulator, A.V.R Sx460 | 1 |
| 32***56 | Alternator | 1 |
| 32***57 | Bearing, Nde | 1 |
Z62-2-1 Alternator, Uci 224e-16
| 32***08 | Regulator, A.V.R Sx460 | 1 |
| 32***57 | Bearing, Nde | 1 |
| 32***69 | Alternator | 1 |
Z62-12-1 Alternator, Accessories
| 32***17 | Unit, Current Transformer, 200-5a | 1 |
| 32***31 | Kit, Voltage Monitor | 1 |
| 32***32 | Kit, Fuse 1a (10 Off) | 1 |
Z62-3-1 Alternator, Uci 224g-16
| 32***08 | Regulator, A.V.R Sx460 | 1 |
| 32***57 | Bearing, Nde | 1 |
| 32***99 | Kit-Rectifier, Service | 1 |
Z62-11-1 Alternator, Accessories
| 32***64 | Unit, Current Transformer | 1 |
| 32***31 | Kit, Voltage Monitor | 1 |
| 32***32 | Kit, Fuse 1a (10 Off) | 1 |
Z63-11-1 Control Unit, Box & Panel Assemblies
| 13***3D | Setscrew | 4 |
| 13***5D | Setscrew, M6 X 20mm Long | 4 |
| 14***6D | Washer, M6 Plain | 8 |
Z63-2-1 Control Box Assembly
| 13***3D | Setscrew | 2 |
| 13***5D | Setscrew, M6 X 20mm Long | 4 |
| 13***5D | Setscrew, M8x20 | 4 |
Z63-1-1 Control Box Assembly
| 13***3D | Setscrew | 2 |
| 13***5D | Setscrew, M6 X 20mm Long | 4 |
| 13***5D | Setscrew, M8x20 | 4 |
Z63-12-1 Control Unit, Box & Panel Assemblies
| 13***3D | Setscrew | 4 |
| 13***5D | Setscrew, M6 X 20mm Long | 4 |
| 14***6D | Washer, M6 Plain | 8 |
Z64-3-1 Circuit Breaker Box, Assembly
| 13***5D | Screw, M5x20 | 6 |
| 13***5D | Setscrew, M6 X 20mm Long | 14 |
| 13***0D | Screw, Set | 2 |
Z64-11-1 Circuit, Breaker, Box Assembly
| 13***5D | Setscrew, M6 X 20mm Long | 86 |
| 13***5D | Setscrew, M8x20 | 37 |
| 14***6D | Washer, M6 Plain | 86 |
Z64-12-1 Circuit, Breaker, Box Assembly
| 13***5D | Setscrew, M6 X 20mm Long | 86 |
| 13***5D | Setscrew, M8x20 | 37 |
| 14***6D | Washer, M6 Plain | 86 |
Z64-1-1 Circuit Breaker Box, Assembly
| 13***5D | Screw, M5x20 | 6 |
| 13***5D | Setscrew, M8x20 | 4 |
| 13***3D | Nut, Self Lock M8 | 1 |
Z64-2-1 Circuit Breaker Box, Assembly
| 13***5D | Screw, M5x20 | 6 |
| 13***5D | Setscrew, M8x20 | 4 |
| 13***8D | Setscrew, M10 X 30 | 1 |
Z65-11-1 Battery Installation
| 13***5D | Setscrew, M8x20 | 2 |
| 13***5D | Setscrew, M10 X 20 | 4 |
| 13***3D | Nut, Self Lock M8 | 2 |
Z65-1-1 Engine Electrics
| 13***8D | Setscrew, M10 X 30 | 2 |
| 13***5D | Screw, M12 X 20mm Long | 2 |
| 13***3Z | Screw, M4 X 16 | 4 |
Frequently asked questions
What engine does the JCB G55Q use?
The JCB G55Q uses a JCB Dieselmax or EcoMAX engine, depending on the specific production series and regional emissions tier.
What is the operating weight of the JCB G55Q?
Operating weight varies by configuration, counterweight setup, and track shoe width, typically falling within the 5.5 to 6.5 metric ton class.
What model replaced the JCB G55Q?
The G55Q is part of the JS-series compact excavator family. Specific successor models depend on the production year and regional market, with newer JS-series variants updating engine emissions packages and cab ergonomics.
What G55Q owners discuss
What engine generation is the JCB G55Q equipped with, and what are the known failure patterns for that series?
The JCB G55Q utilizes a Perkins 404D-22 diesel engine. For the broader JCB 444 engine family, early Dieselmax variants (Tier 2 and early Tier 3) are prone to big end bearing failures on the crankshaft, particularly if oil change intervals are extended. Later common rail variants (Tier 4i and T4 Final EcoMax) tend to suffer from injector faults and general wear, with the common rail systems being sensitive to fuel quality. Faulty injectors can cause rough running, white smoke, and poor starting. Have your dealer verify the specific engine tier and serial range for your machine.
What are the typical hydraulic and powertrain behaviors reported for JCB compact equipment?
JCB compact excavators like the 55Z series feature a closed-centre hydraulic system designed for smooth multi-function operation. The G55Q generator set series is documented with electric refuelling pumps and JCB immobilizer systems (unique key or keypad). Operators report that JCB machinery often uses metric and English fittings on hoses, which can complicate repairs as many hose makers do not stock these specific fittings.
What undercarriage or wear patterns are typical for this machine type?
The JCB G55Q is a generator set, not a tracked excavator, so it does not have an undercarriage. However, for the similar 55Z compact excavator class, the zero tail swing design keeps the rear of the machine within the track width, allowing work close to walls and barriers. Wear patterns in this class often involve the track shoes and rollers due to the compact radius and frequent repositioning. For the G55Q, wear is typically concentrated on the engine mounts and ancillary components rather than undercarriage tracks.
What are the common electrical or sensor issues associated with JCB machinery?
Common electrical issues in JCB machinery include failures in the forward/reverse lever microswitches that activate hydraulic solenoids on the transmission body. In generator sets, the digital control panel and immobilizer systems are critical; issues may arise from the unique key or keypad system. Wiring harnesses in JCB skid steer and compact equipment have been noted by operators to use white wiring.
What should be checked when buying a used JCB G55Q?
When inspecting a used JCB G55Q, check the engine data plate to identify the specific engine variant (e.g., Perkins 404D-22 or later EcoMax) to determine likely failure modes. Verify the condition of the electric refuelling pump and the JCB immobilizer system functionality. Inspect the air filtration system, as standard filters may be overwhelmed in dusty environments, leading to accelerated ring and bore wear. Check for any history of big end bearing issues if the machine has high hours and poor maintenance records.
How does the JCB G55Q's engine performance compare to similar class machines?
The JCB G55Q is a generator set, not a construction excavator. For comparison, the similar 55Z compact excavator class uses a Perkins 404D-22 diesel engine with a gross power of 35.7 kW (48 hp). The G55Q's engine performance is tailored for power generation rather than hydraulic flow, with specifications varying by configuration and series.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
Serial-range & configuration variants
This page covers the Jcb G55Q. Related factory variants of the same model family:
G55QG55Q
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