PLATE 8V0409 - Caterpillar

Test Procedure
Note: A temporary setting of the main relief valve is required before any crossover relief valve can be adjusted. Refer to Table 3 for the temporary main relief setting for the function being tested.Note: A continuous relief of the valve for more than 10 seconds is not allowed.
Table 3
Function Temporary Main Relief Setting
Left Travel Forward and Reverse 38200 500 kPa (5541 73 psi)
Right Travel Forward and Reverse
Table 4
Relief Valve Pressure Change With One Turn Of Adjustment Screw
Main relief valve 14400 kPa (2100 psi)
Crossover relief valves 13340 kPa (1925 psi) Note: Pressure values in Table 4 are approximate values. Use a pressure gauge for adjustment.
Illustration 4 g02144721
Travel brake valve (left side)
(5) Adjustment screw
(6) Locknut
(7) Crossover relief valve (forward left travel)
(8) Crossover relief valve (reverse left travel)
(9) Locknut
(10) Adjustment screw
Start the engine.
Place the hydraulic activation control lever in the UNLOCKED position.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Set the engine speed dial to position "10" and AEC switch "OFF".
Move the joystick for the stick until the stick is at the full STICK OUT position (full retraction of stick cylinder).
Check the main relief setting pressure setting at pressure tap (1) and pressure tap (2). The pressure setting should be 35000 500 kPa (5076 73 psi).
Return the joystick to the NEUTRAL position.
Illustration 5 g02142898
Main relief valve (standard)
(A) Adjustment screw
(L) Locknut
Illustration 6 g02143255
Main relief valve (heavy lift)
(A) Adjustment screw
(L) Locknut
Loosen the locknut. Set the temporary main relief pressure to 38200 500 kPa (5541 73 psi). Tighten the locknut. Note: Turn the adjustment screw clockwise in order to increase the pressure. Turn the adjustment screw counterclockwise in order to decrease the pressure.Note: Always make final pressure adjustments on pressure rise.
Verify the temporary main relief pressure setting with a second function. Move the joystick for the boom until the boom is at full BOOM RAISE position (full extension of the boom cylinder). The main relief pressure should be 38200 500 kPa (5541 73 psi).
Illustration 7 g03137183
Sprocket (forward left travel)
(D) Track Block
(4) Sprocket
Place track block (D) in sprocket (4) in order to block forward left travel. Refer to Illustration 7.
Slowly move the left travel control lever to full FORWARD position.
Check the pressure setting of the left forward travel crossover relief.
Loosen the locknut of the left forward travel crossover relief valve. Turn adjustment screw of the left forward travel crossover relief valve until the pressure reading at pressure tap (2) is 35000 kPa (5076 psi).
Slowly move the left travel control lever to full FORWARD position.
Check the pressure setting of the left forward travel crossover relief.
Loosen the locknut of the left forward travel crossover relief valve. Turn adjustment screw of the left forward travel crossover relief valve until the pressure reading at pressure tap (2) is 38200 500 kPa (5541 73 psi). Note: Turn the adjustment screw clockwise in order to increase the pressure. Turn the adjustment screw counterclockwise in order to decrease the pressure.Note: In order to prevent over setting, the adjustment should