SHEET 4256142 - Caterpillar

Illustration 1 g01266656
Pump compartment
(1) Pressure tap (pressure for drive pump)
(2) Pressure tap (pressure for idler pump)
(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.
Illustration 2 g01267081
Set heavy lift switch (A) to the ON setting. Make sure that the indicator light is on.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Raise the boom until the boom cylinder rods are at full extension.
Check the pressure setting of the heavy lift at pressure tap (1).
Return the joystick for the boom to the NEUTRAL position.
Illustration 3 g01241161
(4) Main relief valve
(5) Locknut for the heavy lift
(6) Adjustment screw for the heavy lift
(7) Locknut for the main relief valve
(8) Adjustment screw for the main relief valve Note: When the main relief setting is adjusted, the heavy lift setting is not affected. When adjustment screw (8) is turned counterclockwise in order to decrease the main relief setting, the pressure difference between the main relief setting and heavy lift setting will increase. When adjustment screw (8) is turned clockwise in order to increase the main relief setting, the pressure difference between the main relief setting and heavy lift setting will decrease.Note: When the heavy lift setting is increased, the main relief setting is also increased. When the heavy lift setting is decreased, the main relief setting is also decreased.
The relief valve pressure setting for heavy lift should be 36000 + 500 - 1000 kPa (5221 + 73 - 145 psi). If the relief valve pressure setting for heavy lift is not within the specification, adjust the relief valve pressure setting for heavy lift.
Loosen locknut (5) in