COVER 1357475 - Caterpillar

Illustration 6 g03729304
Main control valve (M320F)
(1) Main relief valve
(2) Load sensing signal limiter valve
(3) Adjustment screw
(4) Locknut
(5) Adjustment screw
(6) Locknut
Loosen locknut (6) on load sensing signal limiter valve (2).
Turn the adjustment screw (5) of load sensing signal limiter valve (2) clockwise by one half turn.
Tighten locknut (6) on load sensing signal limiter valve (2).
Remove the cap from main relief valve (1).
Loosen the locknut on main relief valve (1).
Turn the adjustment screw clockwise on main relief valve (1) by one quarter turn.
Tighten the locknut on main relief valve (1).
Install the cap onto main relief valve (1).Test Procedure
Start the engine.
Set the engine speed dial at "1".
Lower the left console.
Illustration 7 g02446738
Power mode control button located on the soft panel switch
Push down on the power mode control button in order to activate power mode.Note: The indicator light will be illuminated when power mode is activated.
Illustration 8 g02447036
Automatic Engine Speed Control (AESC) as displayed on the programmable function key in the monitor.
Disable the automatic engine speed control through the monitor by pressing the programmable button.
Illustration 9 g03722432
Hydraulic modulation switch on left joystick
Illustration 10 g06174873
Hydraulic modulation medium mode (monitor display)
Select the hydraulic modulation mode as medium. Press the lower front switch on the left joystick to select the hydraulic modulation mode.
The air conditioning should be turned off for the following test.
Operate the implement that will be tested in the full open position and check the line relief valve pressure at the load sensing signal pressure tap. Refer to Table 1 for the correct pressure.
Operate the implement that will be tested in the full close position and check the line relief valve pressure at the load sensing signal pressure tap. Refer to Table 1 for the correct pressure.
If the line relief valve pressure is not set to the proper specification, refer to the "Adjustment Procedure".
If the line relief valve pressure is set to the proper specification, adjust main relief valve (1) to the original setting and then adjust load sensing signal limiter valve (2) to the original setting.Note: Refer to Testing and Adjusting, "Relief Valve (Main) - Test and Adjust".Note: Refer to Testing and Adjusting, "Relief Valve (Signal Limiter) - Test and Adjust".Adjustment Procedure
Personal injury or death can result from sudden machine movement.Sudden movement of the machine can cause injury to persons on or near the machine.To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.
Illustration 11 g03729918
Main control valve (M318F) (typical example)
(1) Main relief valve
(2) Load sensing signal limiter valve
(7a) Bucket (rod end)
(7b) Bucket (head end)
(8a) Stick (rod end)
(8b) Stick (head end)
(9a) Boom (rod end)
(9b) Boom (head end)
(10a) VA boom (rod end)
(10b) VA boom (head end)
Illustration 12 g03729933
Main control valve (M320F) (typical example)
(1) Main relief valve
(2) Load sensing signal limiter valve
(7a) Bucket (rod end)
(7b) Bucket (head end)
(8a) Stick (rod end)
(8b) Stick (head end)
(9a) Boom (rod end)
(9b) Boom (head end)
(10a) VA boom (rod end)
(10b) VA boom (head end)
Remove the cap from the line relief valve