BAIC HL955 Loader Service Manual & Repair Guide PDF Download (EN)

SECTION 6 WORK EQUIPMENT Group 1 Structure and Function - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6-1 Group 2 Operational Checks and Troubleshooting - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6-41 Group 3 Tests and Adjustments - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6-52 Group 4 Disassembly and Assembly - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6-64

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SECTION 6 WORK EQUIPMENT GROUP 1 STRUCTURE AND FUNCTION 1. HYDRAULIC SYSTEM OUTLINE The loader hydraulic system is a pilot operated, closed center system which is supplied with flow from the variable displacement piston main hydraulic pump. The loader system components are : В Main pump В Main control valve В Bucket cylinder В Boom cylinders В Remote control valve (Pilot control valve, EH type) В Safety valve Flow from the main hydraulic pump not used by the steering system leaves the steering valve (EHPS) EF port. It flows to the inlet port plate of two section or three section block type main control valve.

The main control valve is load pressure independent flow distribution system which routes flow to the boom, bucket or auxiliary cylinders (not shown) when the respective spools are shifted. Flow from the main pump is routed to the main control valve where pump outlet pressure is reduced to pilot circuit pressure. The main control valve flow to the remote control valve. The remote control valve routed flow to either end of each spool valve section in the main control valve to control spool stroke. A accumulator mounted on safety valve supplies a secondary pressure source to operated remote control valve so the boom can be lowered if the engine is off.

The return circuit for the main hydraulic system have return filter inside the hydraulic tank. The return filter uses a filter element and a bypass valve. The bypass valve is located in the upside of filter. 6-1

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2. HYDRAULIC CIRCUIT (HL955, HL955XTD) 2.

HYDRAULIC CIRCUIT (HL955, HL955XTD) LH 20 Control unit 19 8 CL ELECTRONICS 2 4 1 3 EF P 18 L P S P 36 37 PS P2 M T 35 M 1 Main pump 2 Fan & brake pump 3 Main control valve 4 Fan motor 5 Directional valve 6 Oil cooler 7 Check valve 8 Controller (opt) 9 Boom lowering valve 10 Remote control block(EH) 11 FNR remote control lever 12 Remote control valve(HYD) 13 Safety valve 14 Suttle valve 15 Boom cylinder 16 Bucket cylinder 17 Steering cylinder 18 Steering unit 19 Steering valve (EHPS) 20 Joystick steering (opt) 21 Accumulator 22 Orifice 23 Pressure sensor 24 Brake valve 25 Pressure switch 26 Cut off valve 27 Accumulator 28 Accumulator 29 Pressure sensor 30 Hydraulic tank 31 Air breather 32 Return filter 33 By pass valve 34 Strainer 35 Pump motor (opt) 36 Check block (opt) 37 Pressure sensor (opt) 38 Check valve (opt) 39 Ride control velve (opt) 40 Accunulator (opt) 41 Quick coupler cylinder (opt) 42 Solenoid valve (opt) 6-2 15 16 LH RH 23 PS 23 PS a1 a2 a3 9 P A1 B1 A2 B2 A3 B3 3 LS Floating Boom Aux.

Dump Bucket Down Pst Rollback Up T 7 RH 12 21 b1 b2 b3 B.D/F B.U B.I DUMP AUX 22 AUX2 BUCKET BOOM Joystick 40 11 11' Sp. T 39 CR T P 8 Control unit 1 3 4 2 1.1 2.1 (Electro-Hydraulic & Joysick steering) RL 10 EH18 EH17 EH20 EH19 EH22 EH21 T Ba /D2 own B/b up2 Bb /i1 Da um1A pb ux2 dow Tn MAub Cx2 u P n o B 4 1 6(4) 3(2) 5(3) 2(1) ( ) :

2 Spool A Ps FRONT /F B.U B.I DUMP AUX T P 3 4 2 1.1 2.1 b2 b2 b2 B/up Aux down Aux u b1 a1 B/in Dump To MC FRONT Ts LS T a3 b3 a1 7 7 1 R S1 13 X1 X2 14 X3 T 1 38 23PS X1 X2 B1 B2 S1 L2 L1 S2 L4L3 To MCV b1 a2 b2 A1 3 ' P1 T 31 32 3 34 30 P1 T1 A1 25 P2 AXLE T2 A2 27 27 24 28 29 REAR S1 B1 B2 S2 S3 26 PS 41 G1 Parking P B3 29 PS G2 29 T/M 42 2 4 PS PS PP T1 T2 3 1 6 3 2 5 D 4 B P A A B B T S1 L 757F6WE01 S1 L2 3 B S1 a1 a2 A1 B1 p t A2 B2 Floating oom Dum Rollback Bucke Up Down B

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HYDRAULIC CIRCUIT (HL955, HL955XTD, DIRECT STEERING, OPT) HYDRAULIC CIRCUIT (HL955, HL955XTD, DIRECT STEERING, OPT) 40 AUX1 T Sp.

39 11 8 EH17 EH18 EH20 EH19 B A B3 a3 b3 a1 b1 4 1 4 2 6 3 In Bucket Dump Aux Up Aux Down Aux 17 LH 21 24 P1 FRONT T1 A1 25 AXLE T2 P2 A2 19 29 REAR G1 PS 41 B3 C3 PARKING 42 G2 29 PS T/M 2 3 1 4 36 S P 6 37 PS P1 M T 35 5 4 P A D M T B L 1 Main pump 2 Fan & brake pump 3 Main control valve 4 Fan motor 5 Directional valve 6 Oil cooler 7 Check valve 8 Controller (opt) 9 Boom lowering valve 10 Remote control block(EH) 11 FNR remote control lever 12 Remote control valve(HYD) 13 Safety valve 14 Suttle valve 15 Boom cylinder 16 Bucket cylinder 17 Steering cylinder 18 Steering unit 19 Steering valve (EHPS) 21 Accumulator 22 Orifice 23 Pressure sensor 24 Brake valve 25 Pressure switch 26 Cut off valve 27,28 Accumulator 29 Pressure sensor 30 Hydraulic tank 31 Air breather 32 Return filter 33,34 By pass valve, Strainer 35 Pump motor (opt) 36 Check block (opt) 37 Pressure sensor (opt) 38 Check valve (opt) 39 Ride control velve (opt) 40 Accunulator (opt) 41 Quick coupler cylinder (opt) 42 Solenoid valve (opt) 9556WE01 6-2-1 16 15 ET BOOM 11 2/3spool 9 LH RH 23 PS PS tro Hydraulic 23 10 9 EH22 EH21 T a1 a2 a3 P P A1 B1 A2 B2 A3 3 x 5 2 3spool DownFloating 3 1 2spool LS ket Ba o2 omBb o2 om T Mo CV Bucket Boom Dump DownUp Pst back Up Roll T H 21 22 b1 b2 b3 18 4 B.D/F B.U CRAWD DUMP AUX T P 1 3 4 2 1.1 2.1 HYD YD 16 15 LH RH 23 PS PS 23 a2 a3 A1 B1 A2 B2 A3 oating Dump DownFl Bucket Boom back Up Roll 7 7 14 S1 X1 X2 X3 EH EH 13 P1 T H A1 27 2728 S1 B1 B2 S2 S 26 C5 C6 C1 C4 P 29 PS C2 PS PP T1 T 32 33 2 X2 3 1 X1 38 23PS B1 B 2 X2 31 L4 L3 S1 L 34 B 30 S1

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