SHOE 2G7505 - Caterpillar

Table 2
Accumulator Specification
Date Equipment ID Code
Item Specification Actual Engine Speed
Accumulator Charge Pressure 1050 100 kPa (152 15 psi) High Idle Introduction
The accumulator stores hydraulic oil pressure that can be used to lower the implements when the engine is off. The accumulator is on the pilot manifold.The following procedure will determine if the accumulator for the pilot system is charged to the appropriate pressure.Required Tools
Illustration 1 g02726620
Tooling (B)
Table 3
Tool Item Qty Part Number Description
B B1 1 8T-0856 Pressure Gauge
(0 to 6,000 kPa (0 to 870 psi))
B2 1 6V-3989 Fitting
B3 2 6V-4143 Quick Connect Coupler
B4 1 177-7860 Hose As (10 ft) Test Preparation - Accumulator Leak Down
Move the machine to a smooth horizontal location.
Engage the parking brake.
Lower all of the implements.
Stop the engine.
Turn the key to the ON position. Make sure that the implement lockout switch is turned to the UNLOCKED position. Move the implement control levers to all positions several times to release any pressure in the hydraulic system.
Illustration 2 g03664145
(CPG) Pressure tap for the charge pressure of the accumulator
Attach tooling (B) to pressure tap (CPG).Test Procedure - Accumulator Pilot Oil Pressure Leak Down
Start the engine. Warm the hydraulic oil to a minimum temperature of 65° C (150° F).
Record the pressure reading on pressure tap (CPG).
Stop the engine. Turn the key to the ON position but do not start the machine.
With the implement lockout switch in the UNLOCKED position, record the pressure reading at pressure tap (CPG).
The pressure reading should not drop more than 700 kPa (101 psi) in 2 minutes. If a pressure drop greater than 700 kPa (101 psi) occurs, the pilot oil system should be checked for excessive leakage.Adjustment Procedure - Pressure Leak Down
There are no adjustments that can be made to reduce pressure leaks in the system. Investigate the components of the charging system to determine the cause of the system leakage.Test Preparation - Accumulator Charge Pressure
Move the machine to a smooth horizontal location.
Engage the parking brake.
Lower all of the implements.
Stop the engine.
Turn the key to the ON position. Make sure that the implement lockout switch is turned to the UNLOCKED position. Move the implement control levers to all positions several times to release any pressure in the hydraulic system.
Illustration 3 g03664145
(CPG) Pressure tap for the charge pressure of the accumulator
Attach tooling (B) to pressure tap (CPG) on pilot manifold (2). Use the pressure tap (CPG) for the accumulator charge pressure.Test Procedure - Accumulator Charge Pressure
Start the engine. Warm the hydraulic oil to a minimum temperature of 65° C (150° F).
Operate the engine at HIGH IDLE.
Exercise the implement hydraulics. At the accumulator, the pilot pressure at tooling (CPG) should be 3275 170 kPa (475 25 psi).
Shut off the engine. Turn the key to the ON position. The accumulator charge pressure should remain steady until an implement control is exercised.
With the implement lockout switch in the UNLOCKED position, move the implement control out of the HOLD position in any direction to actuate a function. Return the handle to