BODY AS-PISTON 5575686 - Caterpillar

Pump Efficiency Check
For any pump test at a given rpm, the pump flow at 690 kPa (100 psi) will be larger than the pump flow at 6900 kPa (1000 psi). The difference between the pump flow of the two operating pressures is the flow loss.Method of finding loss: Flow loss when expressed as a percent of pump flow is used as a measure of pump performance.Example of finding percent of flow loss: If the percent of flow loss is more than 10%, pump performance is not good enough.*Numbers in examples are for illustration and are not values for any specific pump or pump condition. See Specifications for pump flow of a new pump at 690 kPa (100 psi) and 6900 kPa (1000 psi).Machine Test
Install a Flow Meter. For Formula I, measure pump flow at 690 kPa (100 psi) and at 6900 kPa (1000 psi) with the engine at high idle rpm.Formula I Bench Test
If the test bench can be run at 6900 kPa (1000 psi) and at full pump rpm, find the percent of flow loss using Formula I.If the test bench cannot be run at 6900 kPa (1000 psi) and at full pump rpm, run the pump shaft at 1000 rpm. Measure the pump flow at 690 kPa (100 psi) and at 6900 kPa (1000 psi). Use these values in the top part of Formula II. For the bottom part of the formula, run the pump shaft at 2000 rpm. Measure the pump flow at 690 kPa (100 psi).Formula II Pressure Test Tools
The 4C-4892 Fittings Group can be used to make pressure tests on the machine systems. Before any tests are made, visually inspect the complete hydraulic system for leskage of oil and for parts that are damaged. For some of the tests a magnet and a ... mm (in)measuring rule are usable tools.The 4C-4892 Fittings Group has ORFS connectors and NPT threads on the fittings. ORFS-to-metric and NPT-to-metric adapters must be used as necessary when checking pressures on this machine. When any test is made of a machine system, the hydraulic oil must be at the normal temperature for operation.