BODY 4J6950 - Caterpillar

Table 1
Required Tools    
Part Number    Description    Qty    
8T-0861     Pressure Gauge (
60000 kPa (8700 psi))     1    
Position the machine on level ground and stop the engine.
Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release".
Illustration 1 g00816997
Pump compartment (1) Pressure tap (right pump delivery pressure) (2) Pressure tap (left pump delivery pressure) (3) Pressure tap (power shift pressure)
Attach a 60000 kPa (8700 psi) pressure gauge to pressure tap (1) .
Start the engine.
Place the machine controls at the following settings: engine speed dial "10" and AEC switch OFF. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for engine rpm settings.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Open the bucket until the bucket cylinder rod is at the full retraction.
Check the main relief valve pressure setting at pressure tap (1) .
Return the joystick for the bucket to the NEUTRAL position.
The main relief valve pressure setting should be 34300 500 kPa (4975 73 psi). If the main relief valve pressure setting is not within the specification, adjust the main relief valve pressure setting.
Illustration 2 g00817008
(4) Adjustment screw (5) Locknut (6) Main relief valve
In order to adjust the main relief valve, loosen locknut (5) and turn adjustment screw (4) until the pressure gauge reading at pressure tap (1) is 34300 500 kPa (4975 73 psi).Note: Turn adjustment screw (4) clockwise in order to increase the pressure. Turn adjustment screw (4) counterclockwise in order to decrease the pressure.Note: Always make final pressure adjustments on pressure rise.
Tighten locknut (5) to a torque of 50 10 N m (37 7 lb ft).Temporary Setting of the Main Relief Valve
Note: A temporary setting of the main relief valve is required before any line relief valve can be adjusted.
The main relief valve pressure setting should be 34300 500 kPa (4975 73 psi). If the main relief valve is not within the specification, adjust the main relief valve pressure setting to the correct pressure specification before performing Step 2. Refer to Testing and Adjusting, "Relief Valve (Main) - Test and Adjust".
Illustration 3 g00817008
(4) Adjustment screw (5) Locknut (6) Main relief valve
Loosen locknut (5) and turn adjustment screw (4) clockwise for one quarter turn. Tighten locknut (5) to the specified torque.Note: Always make final pressure adjustments on pressure rise.