D350E Series II, D400E Series II and D400E Series II Ejector Articulated Trucks Braking System Caterpillar

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Personal injury or death can result from sudden machine movement. Sudden movement of the machine or release of oil pressure can cause injury to persons on or near the machine. To help prevent possible injury or death, refer to the information in Testing and Adjusting, "Machine Preparation for Troubleshooting".

The oil supply and the oil pressure is regulated by the pressure and flow compensator valve which is attached to the brake pump.

Illustration 1	g00670041
Location of the Pressure and Flow Compensator Valve (1) Brake pump (2) Locknut (3) Cap (4) Pressure and flow compensator valve

The oil pressure from the brake pump can be checked at the test fitting on the check and pressure reducing valve. The check and pressure reducing valve is located under a hinged cover at the rear of the cab. The hinged cover is attached to the transmission cover.

Illustration 2	g00670088
Location of the Check and Pressure Valve (5) Test fitting

Note: Make sure that the oil is at operating temperature before you perform this test.

Procedure

1. Install 6V-4144 Coupler onto 8T-0859 Pressure Gauge (0 to 25000 kPa (0 to 3600 psi)).

2. Connect the pressure gauge to test fitting (5) on the check and pressure reducing valve with 6V-4142 Fitting (Test), 6V-4143 Coupler and 6V-3079 Pressure Hose Assembly .

3. Start the engine with the parking brake engaged. Run the engine at low idle with the transmission in the NEUTRAL position.

4. The pressure reading on the pressure gauge should register 20340 ± 345 kPa (2950 ± 50 psi).

   Note: If the pressure reading on the gauge is above the specified pressure or below the specified pressure, then adjust the pressure and flow compensator valve.

5. Stop the engine.

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Illustration 3	g00670120
Pressure and Flow Compensator Valve (2) Locknut (3) Cap (4) Pressure and flow compensator valve (6) Adjusting screw

6. Remove cap (3) .

7. Loosen locknut (2) and rotate 360 degrees.

8. Start the engine and run at low idle rpm.

9. Use a suitable allen wrench and turn adjusting screw (6) .

   To increase pump pressure, turn adjusting screw (6) in a clockwise direction.

   To decrease pump pressure, turn adjusting screw (6) in a counterclockwise direction.

10. When the reading on the pressure gauge is 20340 ± 345 kPa (2950 ± 50 psi), tighten locknut (2) .

11. Install cap (3) .

12. Stop the engine and remove the test equipment.

Note: Always test the brake pump before adjusting the pressure and flow compensator valve. Refer to System Operation, Testing and Adjusting, "Pressure for Piston Pump (Brake) - Test".