SHIM 4646162 - Caterpillar

Introduction
Hydraulic oil pressure can remain in the hydraulic system on this machine after the engine and pump have been stopped. Serious injury can result if this pressure is not released before any service is done on the hydraulic system. In order to prevent possible injury, release the hydraulic system pressure before working on any fitting, hose, or hydraulic component.Lower all work tools to the ground before service is started. If the hydraulic system must be serviced, tested, or adjusted with the work tool in the raised position, the work tool and lift cylinders must be supported properly.Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.
Note: Always replace the floorplate when performing tests.A pump efficiency test is designed to tell if a pump is operating within design parameters. A pump efficiency test should be performed if cylinder cycle time is slow.For any pump test, the pump flow that is measured at 690 kPa (100 psi) is larger than the pump flow that is measured at 6900 kPa (1000 psi) at the same rpm.The difference between the pump flow of two operating pressures is the flow loss.Example Test
Note: The oil in the hydraulic system must be the oil which is recommended in the Operation and Maintenance Manual for your machine, and the oil must be at a temperature of 55° 10°C (131° 18°F).Flow loss is measured by using the following procedure:
Table 1
Pump flow