Testing and Adjusting
Hydraulic Oil Contamination - Test
SMCS Code: 3154-008; 3203-008; 4351-008;
Escaping fluid under pressure, even a pinhole size leak,
can penetrate body tissue, causing serious injury, and
possible death. If fluid is injected into your skin, it must
be treated immediately by a doctor familiar with this type
Always use a board or cardboard when checking for a
Personal injury can result from hydraulic oil pressure and
Hydraulic oil pressure can remain in the hydraulic system
after the engine has been stopped. Serious injury can be
caused if this pressure is not released before any service
is done on the hydraulic system.
Make sure all of the attachments have been lowered, oil is
cool before removing any components or lines. Remove
the oil filler cap only when the engine is stopped, and the
filler cap is cool enough to touch with your bare hand.
Care must be taken to ensure that fluids are contained
during performance of inspection, maintenance, testing,
adjusting and repair of the machine. Be prepared to
collect the fluid with suitable containers before opening
any compartment or disassembling any component
Refer to Special Publication, NENG2500, "Caterpillar Tools
and Shop Products Guide", for tools and supplies suitable
to collect and contain fluids in Caterpillar machines.
Dispose of all fluids according to local regulations and
If the oil becomes contaminated, premature component failure
could result. Contaminated oil can also contribute to
Use the following procedure in order to determine the
contamination of the oil in the hydraulic system.
Check the hydraulic filter element for foreign materials.
Bronze colored particles give an indication of pump or
motor port plate failure.
Shiny steel particles give an indication of pump or
motor piston failure.
Rubber particles indicate a seal failure or a hose
Aluminum particles give an indication of steering
and/or charge pump failure.
If any of these particles are found in the hydraulic
filter element, all components of the hydraulic oil
system must be cleaned. Do not use any
damaged parts. Any damaged parts must be
removed and new parts must be installed.
Piston Pump Flow -Test
SMCS Code: 3203-081-FW
This test is designed to determine whether a pump is operating
within design parameters.
For any pump test, the pump flow at 690 kPa (100 psi) will be
larger than the pump flow at 6900 kPa (1000 psi) if the pump is
operating at the same rpm. The pump flow is measured in
L/min (US gpm).
The difference between the pump flow of two operating
pressures is the flow loss.
Method of determining flow loss:
Pump flow at 690 kPa (100 psi)
Pump flow at 6900 kPa (1000 psi)
Example of determining flow loss:
217.6 L/min (57.5 US gpm)
196.8 L/min (52.0 US gpm)
20.8 L/min (5.5 US gpm)