LiuGong CLG920D 921Di 922D Hydraulic Excavator Service Manual January 2021

Description

LiuGong CLG920D 921Di 922D Hydraulic Excavator Service Manual January 2021

This LiuGong CLG920D 921Di 922D Hydraulic Excavator Service Manual January 2021 is the workshop reference for three mid-size LiuGong hydraulic excavators: CLG920D and CLG921Di with the Cummins B5.9 (EPA Tier II) engine, and CLG922D with the Cummins QSB7 (EPA Tier III) engine. Publication number 202101002 is dated January 4, 2021. The book is written for shop technicians and experienced field mechanics who need structure explanations, maintenance standards, machine parameters, performance tests, electrical and hydraulic troubleshooting trees, and step-by-step removal and installation of major assemblies.

File Details

• Manual type: Service Manual (technical guide and workshop guide)
• Brand / models: LiuGong CLG920D, CLG921Di, CLG922D hydraulic excavators
• Engines: Cummins B5.9 (CLG920D / CLG921Di, EPA Tier II); Cummins QSB7 (CLG922D, EPA Tier III)
• Language: English
• Page count: 764
• File format: PDF
• Document number: 202101002
• Date: January 4, 2021

Machines and Engines Covered

The cover and parameter chapter treat the three machines as one family with shared hydraulic architecture and model-specific weights, undercarriage dimensions, and engine ratings. Operating weight is listed as 21000 kg for CLG920D / CLG921Di and 22000 kg for CLG922D. Standard bucket capacity is 0.9 m³ on the 20-ton class machines and 1 m³ on CLG922D. Travel speed is given as 4.9 / 2.9 km/h (high / low) for CLG920D / CLG921Di and 5.0 / 2.8 km/h for CLG922D. Slewing speed is 12 r/min on the B5.9 machines and 10.5 r/min on CLG922D. Gradeability is 35° for all three. Ground pressure with 600 mm shoes is 45.8 kPa (CLG920D / CLG921Di) and 45.6 kPa (CLG922D).

Engine data in the components table is printed as follows. CLG920D: Cummins B5.9, turbocharged air-to-air intercooled, water-cooled, 102 × 120 mm bore × stroke, 5.9 L, compression 17.3:1, ignition 1-5-3-6-2-4, rated 112 kW at 1950 r/min, net 102 kW at 1950 r/min, maximum torque 614 N·m, oil volume 24 L. CLG921Di: same B5.9 architecture, rated 104 kW at 2000 r/min, net 94 kW at 2000 r/min, maximum torque 641 N·m, oil volume 25 L. CLG922D: Cummins QSB7, 107 × 124 mm, 6.7 L, compression 17.2:1, rated 120 kW at 2100 r/min, net 117 kW at 2000 r/min, maximum torque 658 N·m, oil volume 24 L. All three use a 24 V–7.5 kW starter and 24 V–70 A alternator. Section 4.2 also lists QSB7, B5.9-140HP and B5.9-150HP performance rows, including oil-pressure minima at idle and rated speed and thermostat opening temperatures.

The machines are specified for digging and loading earth of I–IV level, optional implements such as backacting shovel, crowd shovel, hydraulic breaker and plum claw, altitude ≤ 3048 m, and ambient temperature −32 °C to 40 °C. Fording depth must not exceed the center of the carrier roller. Working-range figures for CLG922D versus CLG921Di include maximum digging height 9540 mm / 9369 mm, maximum digging depth 6615 mm / 5875 mm, maximum digging radius 9850 mm / 9435 mm, and ISO bucket digging force 159 kN on both listed configurations.

Chapters Covered

• 1 Safety — safety precautions; compressed air; high-pressure fluid; waste liquid; accumulator; asbestos; crush and cut hazards; burns; coolant and oil; battery; fire and explosion; diethyl ether; piping and hose; fire extinguisher and first-aid; thunder; cab protector; accessories; lifting and matching operations; rope selection
• 2 Foreword — how to read the manual; revision marking; general torque specifications; unit conversion; cable identification; coating materials; component weight table; oil usage specifications
• 3 Structural Function and Maintenance — power system (engine related parts; water radiator, hydraulic oil cooler, intercooler and fuel cooler); undercarriage (track frame and tensioner, idler, carrier roller, track roller, sprocket, track); hydraulic system (device layout; main pump; main control valve; center connector; explosion-proof valve; hand and foot pilot valves; cushion valve; travel motor and reduction gear; swing motor and reduction gear; cylinders; hydraulic tank); hydraulic working principle (main circuit, pilot circuit, negative flow control, boom / arm / bucket / swing / travel circuits); work implement maintenance references; A/C pipeline arrangement; electrical system (engine control, display system, auto-idling, instantaneous boost, travel speed control, CLG921Di starting / charging / wiper circuits)
• 4 Parameters — basic machine parameters and dimension drawings; diesel engine performance; complete-machine performance standards
• 5 Testing and Adjusting — complete-machine performance tests (engine speed, travel and driving speed, travel deviation, slewing brake angle and speed, slewing bearing clearance, cylinder action time and settlement, control-lever force and stroke, boom lift and slew, pilot and secondary pilot pressure, solenoid proportional-valve output, main relief setting); other tests (valve clearance, crankcase blow-by, engine oil pressure, track tension, minus-feedback pressures N1 and N2, residual hydraulic pressure release, air exhaust of pump / cylinder / travel motor / attachments, diode check, compressor belt tension, travel motor and reduction-gear performance)
• 6 Fault Diagnosis — precautions and basic checks; electrical faults E1–E23 (battery, auto-idle, start and shutdown, preheater, no implement / swing / travel movement, display, hydraulic-oil temperature display, fuel gauge, wiper, travel alarm, A/C panel and sensors); hydraulic and mechanical faults H1–H13 (swing brake angle, pump noise, no response after start, emulsified oil, oil overheat, swing and travel faults, weak or slow boom / arm / bucket, engine speed drop or stall)
• 7 Removal and Installation — power system (engine, radiator, hydraulic oil radiator, intercooler, water radiator); track travel system (rollers, track, sprocket, idler and tensioner, revolving frame, slewing bearing); covering parts (hood, counterweight); hydraulic system (center joint, tank, main control valve, main pump, travel and hand pilot valves, travel motor and reducer, slewing motor and reducer, including disassembly of several assemblies); work implement (bucket, link and lever, arm, boom, complete implement, boom / arm / bucket cylinders and cylinder overhaul); A/C compressor and evaporator; cab and floor frame
• 8 Attached drawing — hydraulic schematic; CLG920D / CLG922D and CLG921Di electrical schematics; CLG920D / CLG922D A/C schematic and CLG921Di A/C electrical schematic

Taken together, the LiuGong CLG920D 921Di 922D Hydraulic Excavator Service Manual January 2021 is both a systems textbook and a shop teardown book. Chapter 3 explains how the dual axial-piston pumps, 3.9 MPa pilot circuit, negative-flow control, swing-priority and travel circuits actually move oil. Chapter 4 and the test chapter then give the numbers a technician measures against. Chapter 6 turns those same systems into coded electrical trees and hydraulic symptom charts. Chapter 7 is the long workshop section: lift points, residual-pressure release, labeled hose disconnects, torque call-outs and reassembly notes for nearly every major assembly on the machine. Chapter 8 supplies the full-page hydraulic, electrical and A/C drawings needed when tracing a circuit on the machine.

Hydraulic, Electrical and Service Data You Will Use on the Machine

The hydraulic system is described as a double-block axial variable plunger main pump with maximum system flow 2 × 210 L/min. Main relief set pressure is 31.8 MPa, rising to 33.3 MPa during instantaneous supercharging. Boom, arm and bucket outlet safety valves are listed at 37.2 MPa. Slewing-motor relief is 25.5 MPa and travel-motor relief 31.8 MPa. Pilot circuit pressure is 3.9 MPa from a gear-type pilot pump. Boom, arm and bucket cylinders are printed as 2-φ120 × φ85 × 1187 mm (quantity–bore × rod × stroke). Standard boom length is 5680 mm; standard arm is 2910 mm on CLG920D / CLG922D and 2400 mm on CLG921Di.

Electrical architecture is 24 V with two 12 V batteries. The display chapter covers coolant temperature, fuel level, system voltage, engine oil pressure and hydraulic oil temperature indications, plus alarm colors and menu functions. Model-specific control notes include auto-idling and instantaneous boost on CLG920D / CLG922D, two-speed travel on CLG921Di, and separate starting, charging and wiper circuits for CLG921Di. A/C data includes 5000 W refrigerating capacity, 5800 W heating capacity, R134a charge 950 ± 50 g, Denso 10S15C compressor and ND-OIL8 oil.

Oil and interval tables for the QSB7 machine list engine oil 24 L at 500 hours, swing reduction gear 3.4 L at 1000 hours, travel reduction gears 5.5 L × 2 at 1000 hours, hydraulic tank 210 L / system 330 L at 2000 hours, fuel tank 420 L, and cooling system 25 L at 2000 hours. Recommended grades include 15W-40 (API CI-4) engine oil as the factory-fill mark, SAE 85W-140 (API GL-4) for swing reduction, SAE 80W-90 (API GL-4) for travel reduction, and ISO VG 46 hydraulic oil as the marked factory fill, with VG 32 and VG 68 mapped to ambient ranges. Fastener torque tables cover engine mounts, pump, main valve, swing and travel reducers, track shoes (M20-12.9 at 750 N·m), counterweight (M30-10.9 at 1850 N·m), plus 24° cone O-ring fittings and flange connector bolts. A component weight table supports crane selection: engine assemblies 432–496 kg, revolving frame 1882 kg, counterweight 4300 kg (4000 kg is also given for CLG921Di in the R&I chapter), boom 1616 kg, track frame 2711 kg, and so on.

IMAGES PREVIEW

Testing, Diagnosis and Shop Teardown

Performance standards in section 4.3 and the matching procedures in chapter 5 tell the technician how to set hydraulic oil temperature (typically 45–55 °C or 50 ± 5 °C), park the machine, and measure idle speeds, 20 m travel times, 3-revolution track and swing times, travel deflection, cylinder cycle times, 10-minute cylinder settlement, lever forces and strokes, combined boom-lift-and-slew, pilot pressure 3.9–4.1 MPa at high idle, main relief 33.3–34.3 MPa, port-relief values around 35.3–37 MPa, and pump flow 210 × 2 L/min. Engine-side checks include valve-clearance adjustment, crankcase blow-by measurement, oil-pressure measurement, and compressor-belt tension. Hydraulic service steps cover N1 / N2 negative-flow feedback, residual-pressure release, and bleeding the pump, cylinders, travel motors and attachments.

Fault diagnosis is split into electrical codes E1 through E23 and hydraulic-mechanical symptoms H1 through H13. Electrical trees cover a dead battery, no-start, runaway idle, no shutdown, inoperative preheater, dead implements, blank cluster, wrong oil-temperature or fuel-gauge readings, silent travel alarm, and a full set of A/C sensor and servo faults. Hydraulic trees cover excessive swing-stop angle, pump-area noise, no response after start, emulsified oil, overheating oil, one-way or both-way swing faults, one-side travel, travel drift, slow or weak boom / arm / bucket, and sudden engine-speed collapse. Each path assumes the machine is parked level with implements grounded and residual pressure released before connectors or valves are opened.

Chapter 7 is the longest practical section. Power-system R&I includes engine, radiator pack, hydraulic oil cooler, intercooler and water radiator. Undercarriage work covers track rollers, carrier rollers, track groups, sprockets, idler and tensioner, revolving frame and slewing bearing (bearing weights 445 kg on CLG920D / CLG922D and 315 kg on CLG921Di). Hydraulic R&I goes from the center joint and tank through the main control valve and main pump, then into bench disassembly of the travel and hand pilot valves, travel motor/reducer and swing motor/reducer. Implement work covers bucket, link and lever, arm, boom, the complete front, and all three cylinder assemblies plus cylinder overhaul. Cab, floor frame and A/C compressor / evaporator complete the shop coverage. Warnings throughout require battery-negative disconnect, hydraulic-tank venting, slings sized from the weight table, and LiuGong replacement parts when a diagnosis tree calls for a sensor or valve change.

The foreword also points readers to the separate parts catalogue, the operator use-and-maintenance manual, and the Cummins engine parts manual for parts identification and daily operation. This service volume is the document used once the machine is in the bay for measurement, diagnosis or assembly replacement.

Get the Manual and Start Working

With the LiuGong CLG920D 921Di 922D Hydraulic Excavator Service Manual January 2021 on hand you can set main and port relief valves, bleed pumps and motors after a hose change, diagnose a blank monitor or a one-side travel complaint, and lift the engine, pump, main valve, swing bearing or front structure using the printed weights and torque values. Using the published pressures, cycle times and settlement limits keeps a 21–22 t excavator from being reassembled to the wrong spec. After payment you receive the PDF immediately — no shipping, readable on any device, and printable for the toolbox or the machine cab.