DRUM 8H6540 - Caterpillar

Main Relief Valve (Low Setting)
Start the engine.
Place the hydraulic activation control lever in the UNLOCK position.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Place the machine controls at the following settings:
Engine speed dial "10"
AEC switch OFF
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(5) Sprocket
(T) Blocker Pin
Place the blocker pins (T) in both sprockets in order to block forward travel.
Slowly move the both travel control levers to the full FORWARD position.
Check the main relief pressure setting at pressure tap (1). The pressure setting should be 35000 500 kPa (5076 73 psi).
Return the travel control lever to the NEUTRAL position.Adjustment Procedure (High Setting)
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Main Control Valve
(3) Main relief valve (front pump)(boom, bucket, and left travel)
(4) Main relief valve (rear pump)(stick and right travel)
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Main relief valve
(A) Locknut for high main relief setting
(B) Adjustment screw for high main relief setting
(C) Locknut for low main relief setting
(D) Adjustment screw for low main relief setting
Loosen locknut (C) for main relief valve for pump 1 (3) and main relief valve for pump 2 (4).
Turn adjustment screw (D) for both main relief valves clockwise until it stops.
Tighten locknut (C) for both main relief valves.
Loosen locknut (A) for both main relief valves (3), and (4). Turn adjustment screw (B) counterclockwise in order to decrease the main relief pressure until they both reach 30000 500 kPa (4351 73 psi) at full STICK IN position.
Tighten locknut (A) for both main relief valves (3), and (4).
Move the joystick for the stick until the stick is at the full STICK IN position (full extension of stick cylinder).
Check the main relief pressure setting at pressure tap (1). The pressure setting should be 30000 500 kPa (4351 73 psi).
Return the joystick for the stick to the NEUTRAL position.
Loosen locknut (A) for main relief valve (3). Turn adjustment screw (B) clockwise in order to increase the main relief pressure until it reaches 37000 500 kPa (5366 73 psi) at full STICK IN position. Adjust the high main relief pressure setting to the specification.Note: Always make final pressure adjustments on pressure rise.Note: In order to prevent over setting, the adjustment should be stopped immediately after the pressure becomes within specification.
Tighten locknut (A). Do not allow adjustment screw (B) to move.
Move the joystick for the stick until the stick is at the full STICK IN position (full extension of stick cylinder).
Check the main relief pressure setting at pressure tap (2). The pressure setting should be 30000 500 kPa (4351 73 psi).
Return the joystick for the stick to the NEUTRAL position.
Loosen locknut (A) for main relief valve (4). Turn adjustment screw (B) clockwise in order to increase the main relief pressure until it reaches 37000 500 kPa (5366 73 psi) at full STICK IN position. Adjust the high main relief pressure setting to the specification.Note: Always make final pressure adjustments on pressure rise.Note: In order to prevent over setting, the adjustment should be stopped immediately after the pressure becomes within specification.
After adjusting the main relief pressures, recheck