Table of Contents
Troubleshooting
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Summary of Contents for Doosan D20G
- Page 1 SB4219E01 Jan. 2008 Vehicle System Specification System Operation Testing & Adjusting D20G, D25G, D30G with B3.3 Engine D20G, D25G, D30G with 4TNE98 Engine G20G, G25G, G30G with G424F Engine G20G, G25G, G30G with G424FE Engine...
- Page 3 If a tool, procedure, work method or operating technique not specifically recommended by DOOSAN is used, you must satisfy yourself that it is safe for you and others. You should also ensure that the product will not be damaged or made unsafe by the operation, lubrication, maintenance or repair procedures you choose.
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Page 5: Table Of Contents
Index Specification........5 Testing and Adjusting ....32 Hydraulic Control Valve......... 5 Troubleshooting ..........32 Hydraulic Pump ............ 6 Visual Checks ..........32 Lift Cylinder............6 Performance Tests ........32 Standard............6 Hydraulic Oil Temperature (Too Hot) ....32 Full Free Triple and Full Free Lift....7 Hydraulic System and Mast ......33 Tilt Cylinder............ -
Page 6: Index
Tilt Cylinder Alignment ........62 Drift Test............. 63 Steering System ..........64 Steer Wheel Bearing Adjustment....64 Steering Axle Stop Adjustment..... 65 Steering Knuckle Bearing Preload Adjustment ..............65 Steering System Pressure Check....66 ..............66 Brake System ............. 67 Brake System Air Removal ...... -
Page 7: Specification
Specification Hydraulic Control Valve (1) Torque for bolts that hold control valve sections together ..... 40 ± 3 N·m (360±24 lb·in) (2) Adjust main system relief valve pressure for lift and tilt as shown above. See “Relief valve pressure check” in Testing &Adjusting. (3) Adjust auxiliary relief value pressure for the attachment as shown above. -
Page 8: Hydraulic Pump
Hydraulic Pump Lift Cylinder Flow rate of flow protector FFL and FFT Mast D700495........45 to 53 liter/min A215044 ........90 to 106 liter/min STD Mast A371156 ........85 to 90 liter/min Standard (1) Tighten mounting bolts to a torque of .........55 ±10 N·m (440±90 lb·in) (2) Apply Loctite #262. -
Page 9: Full Free Triple And Full Free Lift
Full Free Triple Lift and Full Free Lift Full Free Triple Lift And Full Free Lift Primary Secondary (1) Put pipe sealant on the last three threads of cap. (1) Put pipe sealant on the last three threads of cap. NOTE : All seals to be lubricated with hydraulic oil. -
Page 10: Tilt Cylinder
Cyl. Stroke (X) Cyl. Closed (Z) Part No. Angle* Tilt Angle* mm (in) mm (in) A375282 6° 12° 167 (6.57) 514 (20.24) D20G, G20G A375322 6° 6° 110 (4.33) 571 (22.48) D25G, G25G A375324 6° 4° 92 (3.62) 589 (23.19) -
Page 11: Mast
Mast Carriage (1) With mast at 475 mm (18.7 in) channel lap, equally shim both sides until contact (A) is made (1) Select bearings from the chart to obtain (zero clearance) between bearings and mast minimum clearance (C) between bearings and uprights. - Page 12 Lift Relay Group-Standard Lift WARNING Do not put a lift truck into service if the chain wear indication is 2% or more. A reading of 2% or more could cause damage or injury to persons. (1) Put LOCTITE NO. 242 Thread Lock on the threads of the relay group locknuts after adjustment of the lift chains is completed.
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Page 13: Lift Relay Group - Full Free Lift
Lift Relay Group - Full Free Lift WARNING Do not put a lift truck into service if the chain wear indication is 2% or more. A reading of 2% or more could cause damage or injury to persons. (1) Tighten bolts until contact is made with guard. (2) Put LOCTITE NO. -
Page 14: Lift Relay Group - Full Free Triple Lift
Lift Relay Group - Full Free Triple WARNING Lift Do not put a lift truck into service if the chain wear indication is 2% or more. A reading of 2% or more could cause damage or injury to persons. (1) Maximum chain wear ....Less than 2% (See Chain Wear in TESTING &... -
Page 15: Lift & Tilt Mounting Group
Lift & Tilt Mounting Group pack must not be more than three shims maxi- mum. (2) Install bearing outer race to a depth of (F) ........4.5±0.8 mm (.177±.031 in). (3) Tilt cylinder installation shown. (4) Install bearing outer race to a depth of (G) ...... -
Page 16: Steering Wheel
(9) (Full Free Lift Mast Only) : Steering Wheel Tighten nuts until U-bolt is firm against cylinder, do not apply standard torque. (10) (Full Free Lift Mast Only): With chains adjusted for equal tension run mast to full lift. If mast does not kick (move) to one side, no shims are needed. -
Page 17: Steering Gear
Steering Gear (1) Pin (1) in the body must be aligned with internal pump gear (gerotor) (2) and drive (3) as shown. (4) Tighten bolts in sequence shown. Tighten to a first torque of ........ 14.1±2.8 N·m (125±25 lb·in) Tighten to a final torque of .... 28.2±2.8 N·m (250±25 lb·in) (5) Torque for plug ....11.3 N·m (100 lb·in) Plug to be flush (even) with or below mounting... -
Page 18: Steer Axle And Wheel
Steer Axle and Wheel NOTE : Steer axles with tapered roller bearings shown. (1) Do the steps that follow for steer wheel bearing adjustment. a. Tighten nut (1) slowly to 135 N·m (100 lb·ft) while turning the wheel. b. Loosen nut (1) completely. Tighten it again to ........ -
Page 19: Steer Wheel Mounting
Steer Wheel Mounting Shoe Brake (1) Torque for bolts and nuts that hold steer wheel ........120±20 N·m (90±15 lb·ft) (1) Axle shaft bolt....110±10N·m(81±7.4 lb·ft) (2) Nut ......200±10N·m(148±7.4 lb·ft) (3) Torque for bolts that hold plate to final drive cover ......180±30N·m(133±22 lb·ft) (4) Torque for nuts that hold brake drum to hub .........460±20N·m(339 ±15 lb·ft) Vehicle System... -
Page 20: System Operation
System Operation Hydraulic System Basic Schematic - Standard FFT mast STD mast Engine Basic Hydraulic Actuator System Schematic (1) Lift Cylinder (2) Flow Protector-primary (3) Lift Cylinder-Primary (4) Flow Protector-Secondary (5) Side Shfit Cylinder (6) Tilt Cylinder (7) Control Valve (8) Hydraulic Line (To Steering Unit) (9) Relief valve-Auxiliary (10) Relief Valve-Main (11) Gear Pump (12) Suction Filter (13) Return Filter (14) Hydraulic Tank (15)-(21) Hydraulic Line (22) Flow Regulator Valve Vehicle System System Operation... - Page 21 The hydraulic system has a hydraulic tank (14) and a gear pump (11) which is installed at the engine. The gear pump (11) sends the pressurized fluid through hydraulic line (15) to control valve (7). The first block of control valve contains a steering spool to supply the control flow (12 LPM) through hydraulic line (8) to steering unit with the higher priority.
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Page 22: Optional Schematic With Hyd. Locking System
Optional Schematic with hyd. locking system FFT mast STD mast Engine Basic Hydraulic Actuator System Schematic (1) Lift Cylinder (2) Flow Protector-primary (3) Lift Cylinder-Primary (4) Flow Protector-Secondary (5) Side Shfit Cylinder (6) Tilt Cylinder (7) Control Valve (8) Hydraulic Line (To Steering Unit) (9) Relief valve-Auxiliary (10) Relief Valve-Main (11) Gear Pump (12) Suction Filter (13) Return Filter (14) Hydraulic Tank (15)-(24) Hydraulic Line (25) Flow Regulator Valve (26) Solenoid Block (27) Lift Lock Solenoid (28) Unload Solenoid (29) Emergency Manual Over Ride Valve Vehicle System... - Page 23 In addition to the basic hydraulic operation, there is safety unload function on the first block of control valve that lifting and tilting don’t work even though its lever is shifted, when operator leaves a seat for more than 3 seconds. The solenoid valve (28) for unload function is electrically connected to the electric on-off switch beneath a seat.
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Page 24: Hydraulic Control Valve
Hydraulic Control Valve Control valve has specific section of lift and tilt. Overflow valve and flow-priority valve could be mounted on the side port of inlet. Oil circuit is of parallel with neutral back-flow function. When the spool is in the neutral position, pump is in the free load condition. - Page 25 Working Principle of Lifting Valve Section 1. Neutral Position Oil from the pump returns to the tank through unload path. Working principle of tilting valve 1. Neutral Position 2. Lifting up of spools Oil from the pump returns to the tank through unload Close the unloading path, oil from the pump opens a path.
- Page 26 3. Tilting down of spool While unload path is closed, oil from pump opens a Working Principle of Accessory Valve Section load check through parallel path and flow out from Port B. With the pressure goes up, oil at Port Are 1.
- Page 27 Main Relief Valve 1. Free Action Condition of relief valve When the circuit pressure is lower than the rated values, relief valve keeps balance. Pressure at Port P is filled in the spring chamber through poppet throttle hole. By the work of spring force and oil pressure, main poppet is squashed into the seat of slip while the pilot poppet is also in the condition of close by the force of spring.
- Page 28 PF Relief Valve Working principle is same as main relief valve. Instruction is omitted here. Over-load Relief Valve (Port Over-flow Valve) Working principle is same as main relief valve. Below is only the description of cavitation-proof. When working port pressure is lower than that off low-back port, main poppet is open and flow-back oil goes into working port to play the function of cavitation.
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Page 29: Steering System
Steering System Steering Cylinder Steering cylinder (1) gives power assistance through the use of pressure oil at either end of the cylinder piston. The steering cylinder is double ended and the body of the cylinder is mounted stationary to the steer axle. -
Page 30: Steering Gear
Steering Gear Steering Gear (1) Spool. (2) Sleeve. (3) Outlet (to tank). (4) Inlet (for pump oil). (5) Internal pump gear. (6) External pump gear. (7) Centering springs. (8) Pin. (9) Left turn port. (10) Right turn port. (11) Body. (12) Drive. (A) Control section. (B) Metering section. Lift trucks use the non load sensing, open center (oil The metering section is a small hydraulic pump. - Page 31 Oil Flow The oil from the priority valve flows through inlet (4). When the steering wheel is stationary (NEUTRAL), the oil is stopped by spool (1). The oil can not flow through the steering gear to the steering cylinder until the steering wheel is turned. The steering wheel is connected to spool (1) by a shaft assembly and splines.
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Page 32: Brake System
Brake System Master Cylinder (2) Master cylinder Brake fluid from remote reservoir (1) to replenish master cylinder (2). The master cylinder has a piston which pushes brake liquid into the brake lines. The reservoir, located on the cowl, is connected to inlet of master cylinder. -
Page 33: Shoe Type Brake
Shoe Type Brake Automatic Adjustment Brakes with automatic adjustment are adjusted on the reverse braking action. In this example the drum rotation is counterclockwise (in reverse) which causes a counterclockwise rotation of the brake shoes. Secondary shoe (4) moves away from cylinder (2) that causes link (1) to move toggle lever (6) in a clockwise rotation. -
Page 34: Testing And Adjusting
Testing and Adjusting Visual Checks Troubleshooting A visual inspection of the hydraulic system and its components is the first step when a diagnosis of a Troubleshooting can be difficult. A list of possible problem is made. Lower the carriage to the floor and problems and corrections are on the pages that follow these inspections;... -
Page 35: Hydraulic System And Mast
3. The setting on the relief valve is too low. Problem: The hydraulic system will not lift the load. 4. Too many restrictions in the system. Probable Hydraulic Cause: 5. Hydraulic oil level in the tank is too low. 1. There is an air leak, which lets air into the 6. - Page 36 8. Seals in tilt cylinder worn or damaged. Probable Mechanical Cause: 9. Unload function doesn’t work correctly. 1. The mast is not in alignment with the other lifting components and does not slide freely. Probable Mechanical Cause: 2. Not enough lubricant on the parts of the mast that move.
- Page 37 The probable Hydraulic cause: 1. Sleeve in a solenoid valve for unload function is stuck to a housing. button of an emergency manual override valve in solenoid block Unload solenoid in solenoid block Probable Electric Cause: 1. Not to supply the electric power to solenoid valve in solenoid block.
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Page 38: Hydraulic Pump
Problem: The lift or tilt cylinders do not hold 7. The system operates at too high a pressure. their position with the valve control levers in neutral position. a. Relief valve setting too high. b. Attachment components cause a restriction Probable Electric Cause during movement. -
Page 39: Hydraulic Control Valve
Problem: Spools do not return to neutral. Hydraulic Control Valve Probable Cause: Problem: The control spools do not move freely. 1. The springs are broken. Probable Cause: 2. The spool is bent. 1. The temperature of the oil is too high. 3. -
Page 40: Steering System
Problem: Foreign material behind the wiper Problem: Low oil pressure. rings causing scratches on the cylinder rod. Probable Cause: Probable Cause: 1. Low oil level. 1. The wiper rings show wear and do not remove dirt and foreign material. 2. Priority valve relief valve spring weak. 3. -
Page 41: Brake System
Problem: The temperature of the oil is too hot. Problem: Pedal resistance is not solid (spongy). Probable Cause: Probable Cause: 1. The viscosity of the oil is wrong. 1. Leakage or low fluid level. 2. Air mixed with the oil. 2. -
Page 42: Parking Brake
Problem: Brake will not make application. Probable Cause: 1. Leakage or low fluid level. 2. Lining surface looks like glass (glazed), or worn. 3. Oil or brake fluid is on the lining. 4. Air in the brake hydraulic system. 5. Defective master cylinder. 6. -
Page 43: Hydraulic System
Hydraulic System Relief Valve Pressure Check CONTROL VALVE Kgf/ ITEM ㎠ LIFT (2630 18100 (181± (185± TILT ±35) ±250 2.5) 2.5) NON EU 2.0t LIFT (3130 21550 (216± (220± TILT ±35) ±250 2.5) 2.5) LIFT (2840 19500 (195± (199± Pressure Tap Location TILT ±35) ±250... - Page 44 Tilt and Sideshift Relief Valve Check and Adjustment 1. Start the engine and activate the hydraulics until the hydraulic oil is at the normal operating temperature. Put the mast in the full tilt back position. 2. With the engine at high idle, hold the tilt control lever in the full tilt back position and watch the gauge.
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Page 45: Lift Cylinder Air Removal (Only Fft & Ffl Mast)
6. Repeat Steps 4 and 5 until there are no air Lift Cylinder Air Removal (Only FFT & bubbles at the setscrews. FFL Mast) 7. After all the air is removed, tighten the setscrews After the lift cylinder has been disassembled and to a torque of 5 to 7 N·m (45 to 60 lb·in). -
Page 46: Delayed Engine Shutdown System
Delayed Engine Shutdown System Operation The delayed engine shutdown system will shut the engine down if no proper action is taken by the operator. This system makes use of the engine oil pressure switch, transmission oil temperature switch and water (coolant) temperature sensor to get the required truck condition. -
Page 47: Diagram Of Delayed Engine Shutdown System
Diagram of Delayed Engine Shutdown System G20/25/30G G424F(E) ENGINE – LP TRUCK G20/25/30G G424F(E) ENGINE – GAS TRUCK Vehicle System Testing and Adjusting... -
Page 48: Trouble Shooting Of Delayed Engine Shutdown System
Trouble shooting of Delayed Engine Shutdown System When the ignition key is turned on, the MIL Lamp will illuminate and remain on until the engine is started. Once the engine is started, the MIL Lamp will go out unless one or more fault conditions are present. If a detected fault condition exists, the fault or faults will be stored in the memory of the small engine control module (SECM). -
Page 49: Delayed Engine Shutdown System Schematic
Delayed Engine Shutdown System Schematic DELAYED ENGINE SHUTDOWN : G20/25/30G G424F(E) - LP Vehicle System Testing and Adjusting... -
Page 50: Delayed Engine Shutdown System Schematic
Delayed Engine Shutdown System Schematic DELAYED ENGINE SHUTDOWN : G20/25/30G G424F(E) - GAS Vehicle System Testing and Adjusting... -
Page 51: Oss (Operator Sensing System)
OSS (Operator Sensing System) 4. Water separator (sediment) warning – only diesel Operation Water separator lamp indicates when the engine is running and there is much water in the fuel filter Operator Sensing System is operated by seat switch exceeding 100cc. built into the seat. -
Page 52: Operator Sensing System Schematic
Operator Sensing System Schematic Vehicle System Testing and Adjusting... -
Page 53: Trouble Shooting Of Operator Sensing System
Trouble shooting of Operator Sensing System CONDITION PROBABLE FAULT CORRECTIVE ACTION 1. Buzzer warning 1. Seat switch open 1. Check seat switch 2. Parking brake 2. Parking brake switch open 2. Check parking brake switch light 3. Controller defect 3. Check continuity of wire from seat switch to controller (SW2) 4. - Page 54 CONDITION PROBABLE FAULT CORRECTIVE ACTION 1. Check seat switch 1. Buzzer 1. Seat switch open warning 2. Fift lock / Unload 2. Check Lift lock/Unload Solenoid 2. Mast interrupt solenoid defect 3. Check continuity of wire from solenoid-lift lock(2) or light 3.
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Page 55: Mast And Carriage
Mast and Carriage Mast And Carriage Bearings Mast Adjustment Part No. Bearing Size Bearing O.D.* NOTE: The Standard, Full Free Lift and Full Free D581814 Under Size 108.6 mm (4.276 in) Triple Lift mast load bearings are all adjusted the D581815 Standard 109.6 mm (4.135 in) - Page 56 Mast Adjustment Lower Bearings (A) Zero clearance. (B) Minimum clearance. (C) Zero clearance. (3) Bearing. (4) Bearing. (5) Shims. (6) Shims 3. Install 1 mm shim to each bearing of intermediate lower and stationary upper basically. Lifting by crane, insert intermediate mast into stationary mast from the upper side.
- Page 57 B. Upper Bearing Adjustment of Stationary Mast 5. In case of standard and full free mast, inner lower bearings can be easily extruded by pulling down 1. Lift by crane, and pull out intermediate mast from the inner mast from the bottom of stationary mast. stationary mast.
- Page 58 C. Upper Pad Adjustment 2. Make sure stationary mast upper bearings are properly shimmed by rolling up and down and moving intermediate mast to right and left. If clearance between both masts can be detected, pull out the intermediate mast from the stationary mast with crane and add shim 0.5 mm or 1 mm to both stationary upper bearings.
- Page 59 D. Lower Bearing Adjustment of Inner Mast 2. Find narrowest point by ruler on the intermediate mast in the area where the inner lower bearings make contact full length of intermediate mast excluding minimum channel lap 475 mm (18.7 in). Mast Adjustment Lower Bearings (A) Zero Clearance.
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Page 60: Carriage Adjustment
Carriage Adjustment NOTE : The standard, Full Free Lift and Full Free Triple Lift carriage load bearings are all adjusted the same way. The Full Free Triple Lift carriage is shown in the following illustrations. To make the carriage clearance adjustments, carriage must be removed from the mast. -
Page 61: Chain Adjustment
Mast And Carriage Bearings Part No. Bearing Size Bearing O.D.* D581814 Under Size 108.6 mm (4.276 in) D581815 Standard 109.6 mm (4.135 in) D581816 Over Size 110.7 mm (4.358 in) *Permissible tolerance ±0.08mm (.003in) 5. Tighten screw (5) that holds the top bearings to the carriage to a torque of 34L7 N·m (25L5 lb·ft) Chain Adjustment Chain Adjustment Check... -
Page 62: Chain Wear Test
Chain Adjustment Chain Wear Test If the tension is not the same on both chains, do the Chain wear test is a measurement of wear of the procedure that follows: chain links and pins. Do the steps that follow to check chain wear. -
Page 63: Carriage And Mast Height Adjustment
Carriage and Mast Height Adjustment Forks Parallel Check 1. Move the mast either forward or backward so it is 1. Lift the mast and operate the tilt control lever, until in the vertical position. the top surface of the forks is parallel with the floor. Place two straight bars, that are the same width 2. -
Page 64: Tilt Cylinder Alignment
Tilt Cylinder Length Check Tilt Cylinder Alignment If the tilt cylinders are out of alignment, extra stresses in the mast assembly and the mast hinge area will result. To prevent damage, the tilt cylinders must stop evenly at the end of the tilt back and tilt forward strokes. -
Page 65: Drift Test
Drift Test WARNING Drift is movement of the mast or carriage that is Tilt cylinder pivot eyes can loosen if the torque there sult of hydraulic leakage in the cylinders or on the pivot eye clamping bolt is not tight control valve. -
Page 66: Steering System
Steering System Drift Test For The Tilt System Steer Wheel Bearing Adjustment 1. Put a rated capacity load on the forks on the lift truck. Operate the lift truck through a complete lift and tilt cycle until the oil is at normal temperature for operation, 45 to 55°C (113 to 131°F). -
Page 67: Steering Axle Stop Adjustment
Steering Axle Stop Adjustment Steering Knuckle Bearing Preload Adjustment Steer Angle (1) Bolt. (2) Nut. (3) Bolt. (A) 76°angle. Use the procedure that follows to make an Steering Knuckle Bearing Preload Adjustment adjustment to the steer axle turning angle. (4) Steering link. (5) Shims. (6) Bearing. 1. -
Page 68: Steering System Pressure Check
5. The indication on the pressure gauge must be the Steering System Pressure Check priority valve relief setting of 9,000 +0 /+300 kPa (1,305 +0 /+43 psi). If the indication is correct and If the steering system does not work correctly, check a problem exists, then there is possibly a the hydraulic tank for the correct oil level and the mechanical failure in the steering system. -
Page 69: Brake System
Brake System Brake Adjustment The brakes make an adjustment automatically when Brake System Air Removal an application is made in reverse, but only after an application has been made in the forward direction. Systems With Remote Reservoir With each reverse brake application, there happens an adjustment until the lining-to-drum clearance is made small enough to stop the movement of the automatic adjustment linkage. - Page 70 Pedal Adjustment The brake pedal must have proper free play to let the master cylinder piston return to the release position and open the relief outlet. Approximately 5 mm of free play on the pedal is required. Hydraulic pressure in the brake lines goes back through the relief opening and releases the brakes.
- Page 71 2. Adjust stopper bolt for the brake pedal to meet 130 ~135 mm (A) between end of pedal & floor 353 mm plate. For reference, the distance (B) between the top of transmission and pedal shown below is about 353 130 ~ 135 mm 3.
- Page 72 4. Adjust the push rod clearance for the brake 7. Make sure the same level of 2 pedals. master cylinder. The required free play on the brake pedal is about 3 ~ 8 mm. 8. Finally check the distance between floor plate & end of brake pedal should be 130 mm.
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Page 73: Parking Brake Test
Parking Brake Test Parking Brake Adjustment WARNING To prevent personal injury, the operator must be ready to use the service brake if the parking brake is not adjusted correctly and the lift truck starts to move. 1. Drive the fully loaded lift truck up a 15% incline. 2.
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