SLEEVE 8W7881 - Caterpillar

Illustration 1 g06054637
Under Cab
(1) Vibratory pumpVibratory pump (1) is located under the operator platform. For open platform machines, the side panels under the operator platform must be removed in order to provide access to this pump.Vibratory pump (1) is the second in a series of two pumps which are driven by the engine flywheel. The propel pump is driven by the engine, and the vibratory pump is splined to the propel pump. The vibratory pump is an axial piston pump with a variable displacement.
Illustration 2 g06054640
Bottom of Vibratory Pump
(2) Solenoid "B"
(3) Frequency adjustment screw (for low amplitude)
(4) Solenoid "A"
(5) Combination valve
(6) Port "MB"
(7) Charge relief valve
(8) Combination valve
(9) Port "MA"The vibratory pump is controlled by two solenoids. On machines with the fixed frequency vibratory system, the pump control solenoids are on/off solenoids. On machines with the variable frequency vibratory system, the pump control solenoids are proportional solenoids.The control solenoids and the inclusion of frequency adjustment screws are the only difference between the hydraulic pumps used on the two different vibratory systems. Only the fixed frequency pump has frequency adjustment screws (displacement limiters). The machine ECM controls the vibratory pump solenoids on both vibratory systems.Solenoid "A" (4) is located on the top of the pump for both vibratory systems. On machines with the fixed frequency vibratory system, solenoid "A" is energized when the vibratory system is operating in high amplitude. When this solenoid is energized, supply pressure can be measured at port "MA" (9), and return circuit pressure can be measured at port "MB" (6).On variable frequency machines, the machine ECM uses solenoid "A" (4) to control the vibration frequency when the vibratory status is set to low amplitude. When this solenoid is energized, supply pressure can be measured at port "MB" (6), and return circuit pressure can be measured at port "MA" (9).The solenoid "B" (2) is located on the bottom of the pump. On machines with the fixed frequency vibratory system, this solenoid is energized when the vibratory system is operating in low amplitude. When this solenoid is energized, supply pressure can be measured at port "MB" (6), and return circuit pressure can be measured at port "MA" (9).On variable frequency machines, the machine ECM uses solenoid "B" (2) to control the vibration frequency when the amplitude status is set to high amplitude. When this solenoid is energized, supply pressure can be measured at port "MA" (9), and return circuit pressure can be measured at port "MB" (6).On machines with the fixed frequency vibratory system, the pump is equipped with two frequency adjustment screws. The frequency adjustment screws are displacement limiters. The frequency adjustment screw for high amplitude (not shown) is located on the left face of the pump. This adjustment screw