CRANKSHAFT BEARING REPLACEMENT GROUPS 7S8302 - Caterpillar

Pump Operation
Pump Assembly
(1) Reservoir. (2) Wiper blade. (3) Pump element. (4) Relief valve. (5) Inlet fitting. (6) Outlet line. (7) Pump housing.
Hydraulic schematic
(1) Reservoir. (2) Wiper blade. (3) Inlet fitting. (4) Housing. (5) Outlet line. (6) Relief valve. (7) Pump element. (12) Check valve. (17) Electrical motor.
Pump (Charging stage)
(7) Pump element. (8) Eccentric. (9) Piston. (10) Spring. (11) Valve seat. (12) Check valve. (13) Passages. (14) Piston chamber. (16) Spring.The electric motor (17), pump element (7) and eccentric (8) are located in housing (4). The electric motor (17) causes wiper blade (2) and eccentric (8) to rotate clockwise. Wiper blade (2) forces lubricant from the reservoir (1) to pump element (7). When pump element (7) is in the charging stage, piston (9) is shifted to the left by the force of spring (10). Spring (16) forces check valve (12) against valve seat (11). Lubricant is forced by wiper blade (2) thru passages (13) and into piston chamber (14).
Pump (Delivery stage)
(7) Pump element. (8) Eccentric. (9) Piston. (10) Spring. (12) Check valve. (14) Piston chamber. (15) Discharge chamber. (16) Spring.As eccentric (8) continues to rotate clockwise, piston (9) is forced to the right compressing spring (10). The lubricant in piston chamber (14) forces check valve (12) to the right compressing spring (16). This opens a passage between piston chamber (14) and discharge chamber (15). Lubricant is forced out of discharge chamber (15) and into outlet line (5) at a rate of 2.8 cc/min at 1000 kPa (1450 psi). Relief valve (6) limits system pressure to 35 000 kPa (5075 psi). If lubricant is leaking at relief valve (6), it indicates that one of the metering devices or delivery lines is restricted. This restriction will cause a pressure switch to signal the operator of an obstruction in the lubrications system. See "Troubleshooting" section and "Monitoring systems and cab features" in this module.Metering Devices
Lubrication system
(1) Pump assembly. (2) Main line. (3) Main metering device. (4) Secondary metering devices.Operation
There are progressive piston type metering devices used to accurately distribute the lubricant to the lubrication points. The metering devices differ in number of outlets but are identical in operation.After the lubricant is discharged from the pump elements, it enters the main delivery lines (2). It then enters the main metering devices (3) and then to secondary metering devices (4) or directly routed to the lubrication points.Inside the metering devices internal pistons move in a given progressive sequence in repetitive cycles. Each piston must complete its entire movement before the next piston is able to move. All pistons are interdependent. The pistons can not be interchanged. If removed, each must be returned to the original cylinder. Sequence of operation.
Phase 1 of lubricant metering
(A) Piston. (2) Outlet.Lubricant enters the metering device and flows in direction of arrow. Lubricant pressure causes piston (A) to shift to left. The lubricant in front of piston (A) now exists outlet (2).
Phase 2 of lubricant metering
(B) Piston. (7) Outlet. (9) Passage.After piston (A) is at the extreme left position passage