773E and 775E Off-Highway Truck Hydraulic System: Relief Valve (Rear Brake Oil Cooler) - Test and Adjust

Table 1

Tools Needed	Qty
2J-5608 Cover	1
4J-0527 O-Ring Seal	1
6V-3079 Pressure Hose Assembly	1
6V-4143 Coupler Assembly	2
8T-0854 Pressure Gauge ( 1000 kPa (145 psi))	1

Note: Make sure that the filters and the screens are clean before you test any pressures. Make sure that the oil is at operating temperature before you perform this test.

(1) Pressure tap

(2) Hose(3) Rear brake oil cooler relief valve

(3) Rear brake oil cooler relief valve(4) Shims

1. Use couplers to connect a hose to pressure tap (1) .

2. Install an 8T-0854 Pressure Gauge (0 to 1000 kPa (0 to 145 psi)) to the hose.

3. Remove hose (2) from the hoist control valve.

4. Install a 2J-5608 Cover and install a 4J-0527 O-Ring Seal between hose (2) and the hoist control valve.

5. Install hose (2) with longer bolts.

6. Move the hoist control lever to the HOLD position and start the engine.Note: Perform this test at low idle.

7. Look at the pressure gauge. The pressure reading should be 586 ± 14 kPa (85 ± 2 psi).Note: The pressure reading was the result of bench testing the relief valve at a flow rate of 38 L/min (10 US gpm). The flow rate of the pump at low idle is 160 L/min (42 US gpm). The resulting pressure may be higher than the value that is provided.

8. Stop the engine.

9. Remove the test equipment and install the original bolts in the hoist control valve.

Table 2

Shims For Adjusting The Relief Valve Pressure Setting
Part Number	Thickness	Pressure Change
8B-4624	0.81 mm (0.032 inch)	30 kPa (4 psi)

Problem: The pressure is less than 586 ± 14 kPa (85 ± 2 psi).

Probable Cause

• Rear brake oil cooler relief valve (3) is stuck open.
• Rear brake oil cooler relief valve (3) is set too low. Add shims (4). Refer to Table 2.

Problem: The pressure is greater than 586 ± 14 kPa (85 ± 2 psi).

Probable Cause

• Rear brake oil cooler relief valve (3) is set too high. Remove shims (4). Refer to Table 2.

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773E and 775E Off-Highway Truck Hydraulic System: Relief Valve (Rear Brake Oil Cooler) - Test and Adjust 2013-01-10T19:18:00-08:00 Rating: 4.5 Diposkan Oleh: Unknown