2001/10/15 Caterpillar

Wheel Loader:

924G (S/N: 3PZ1-UP; 9SW1-UP; AAN1-UP)

924GZ (S/N: 3DZ1-UP; 6YW1-UP; AAB1-UP)

Testing and Adjusting Module, RENR3511, "924G and 924Gz Hydraulic System ", "Line Relief Valve Test and Adjust". Changes have been made to the pressures and the test procedures of the line relief valves.

Replace Table 12 with the following Table 12.

Table 12

Settings for Line Relief Valves
Cylinder	Head End	Rod End
Tilt (924G)	12307 ± 172 kPa (1785 ± 25 psi)	27579 ± 345 kPa (4000 ± 50 psi)
Tilt (924Gz)	27579 kPa (4000 psi)	18616 ± 345 kPa (2700 ± 50 psi)
Auxiliary for the third function hydraulic arrangement	27579 kPa (4000 psi)	27579 kPa (4000 psi)
Auxiliary for the fourth function hydraulic arrangement	27579 kPa (4000 psi)	27579 kPa (4000 psi)

Replace the "Auxiliary Line Relief Valves for the Third Function Hydraulic Arrangement" procedure with the following "Auxiliary Line Relief Valves for the Third Function Hydraulic Arrangement" procedure.

Auxiliary Line Relief Valves for the Third Function Hydraulic Arrangement

1. Install an 8T-0860 Pressure Gauge (40000 kPa (5801 psi)) on a 6V-3014 Hose Assembly.

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Illustration 1	g00621281
Bank valve (1) Test port for the pressure of the piston pump for the work tools. (2) Line relief valve for the rod end of the tilt cylinder. (3) Line relief valve (auxiliary cylinder rod end). (4) Line relief valve (auxiliary cylinder rod end). (5) Test port for the pressure for the float detent.

2. Install the other end of the hose assembly on the test port for the pressure of the piston pump (1).

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Illustration 2	g00643873
Location of the test port (6) for the signal pressure of the piston pump, nut (7), and screw (8) for adjusting the high pressure cutoff of the pump.

3. Loosen nut (7). Turn the adjusting screw (8) clockwise in order to increase the pressure. Turn the adjusting screw (8) counterclockwise in order to decrease the pressure. Increase the high pressure cutoff adjustment of the pump to 30000 kPa (4351 psi).

4. Start the engine and run the engine at LOW IDLE.

Note: In the following steps, do not keep the auxiliary control lever in the ENGAGED position for more than five seconds while the pressure is at the line relief valve setting. This may cause rapid heating of the hydraulic oil.

5. Observe the pressure gauge and move the control lever to the ENGAGED position. The position of the control lever will depend on the line relief valve that is being tested.

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Illustration 3	g00621586
Line relief valve (9) Seat. (10) Poppet valve. (11) Spring. (12) Nut. (13) Adjuster.

6. If the line relief valve is not set to the correct specifications, stop the engine. Adjust the line relief valve.

   1. Loosen locknut (12). Turn adjusting screw (13) clockwise in order to increase the relief valve setting. Turn adjusting screw (13) counterclockwise in order to decrease the relief valve setting.

   2. After adjusting screw (13) is turned for an adjustment, tighten locknut (12) to a torque of 4 ± 1 N·m (3 ± 1 lb ft).

   3. Start the engine.

   4. Observe the pressure gauge, and move the control lever to the ENGAGED position.

7. When all pressure settings are correct, return the high pressure cutoff adjustment of the implement pump to 25850 ± 350 kPa (3750 ± 50 psi).

Replace the "Auxiliary Line Relief Valves for the Fourth Function Hydraulic Arrangement" procedure with the following "Auxiliary Line Relief Valves for the Fourth Function Hydraulic Arrangement" procedure.

Auxiliary Line Relief Valves for the Fourth Function Hydraulic Arrangement

1. Install an 8T-0860 Pressure Gauge (40000 kPa (5801 psi)) on a 6V-3014 Hose Assembly.

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Illustration 4	g00621281
Bank valve (1) Test port for the pressure of the piston pump for the work tools. (2) Line relief valve for the rod end of the tilt cylinder. (3) Line relief valve (auxiliary cylinder rod end). (4) Line relief valve (auxiliary cylinder rod end). (5) Test port for the pressure for the float detent.

2. Install the other end of the hose assembly on the test port for the pressure of the piston pump (1).

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Illustration 5	g00643873
Location of the test port (6) for the signal pressure of the piston pump, nut (7), and screw (8) for adjusting the high pressure cutoff of the pump.

3. Loosen nut (7). Turn the adjusting screw (8) clockwise in order to increase the pressure. Turn the adjusting screw (8) counterclockwise in order to decrease the pressure. Increase the high pressure cutoff adjustment of the pump to 30000 kPa (4351 psi).

4. Start the engine and run the engine at LOW IDLE.

Note: In the following steps, do not keep the auxiliary control lever in the ENGAGED position for more than five seconds while the pressure is at the line relief valve setting. This may cause rapid heating of the hydraulic oil.

5. Observe the pressure gauge and move the control lever to the ENGAGED position. The position of the control lever will depend on the line relief valve that is being tested.

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Illustration 6	g00621586
Line relief valve (9) Seat. (10) Poppet valve. (11) Spring. (12) Nut. (13) Adjuster.

6. If the line relief valve is not set to the correct specifications, stop the engine. Adjust the line relief valve.

   1. Loosen locknut (12). Turn adjusting screw (13) clockwise in order to increase the relief valve setting. Turn adjusting screw (13) counterclockwise in order to decrease the relief valve setting.

   2. After adjusting screw (13) is turned for an adjustment, tighten locknut (12) to a torque of 4 ± 1 N·m (3 ± 1 lb ft).

   3. Start the engine.

   4. Observe the pressure gauge, and move the control lever to the ENGAGED position.

7. When all pressure settings are correct, return the high pressure cutoff adjustment of the implement pump to 25850 ± 350 kPa (3750 ± 50 psi).