Pressure Override Relief Valve - Test and Adjust
SMCS Code: 5117-025; 5117-081
Personal injury or death can result from sudden machine
Sudden movement of the machine can cause injury to
persons on or near the machine.
To prevent injury or death, make sure that the area around
the machine is clear of personnel and obstructions before
operating the machine.
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 product. Be prepared to collect
the fluid with suitable containers before opening any
compartment or disassembling any component containing
Refer to Special Publication, NEN G2500, "Caterpillar
Tools and Shop Products Guide" for tools and supplies
suitable to collect and contain fluids on Caterpillar
Dispose of all fluids according to local regulations and of
all fluids mandates.
Before you conduct the test procedure on the pressure
override relief valve (POR valve), the following steps must be
Make sure that the parking brake is applied.
Place the propel control lever in NEUTRAL position.
Place the machine in position against a solid, stationary
object such as a loading dock. The wheels and the
drum may be blocked instead of placing the machine
against a stationary object.
Follow the same test procedure and the same
adjustment procedure for the POR valves on the
axle propel pump and the drum propel pump.
Drum Drive Motor
(1) Brake line.
Remove brake line (1) from the drum drive motor. Plug
the brake line and cap the fittings.