Check all oil lines, all hoses, and all connections for
damage and for leaks. Look for oil on the ground under
If oil can leak out of a fitting or out of a
connection, air can leak into the system. Air in
the system is as harmful as having too little oil.
SMCS Code: 3000-035
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, NENG2500, "Caterpillar Tools
and Shop Products Guide" for tools and supplies suitable
to collect and contain fluids on Caterpillar products.
Dispose of all fluids according to local regulations and
The checks during operation can be used to find
leakage in the system. These checks can also be
used to find a bad valve, a bad pump, or a bad
motor. Travel speed can be used to check the
condition of the propel motors and the pump.
Operate the machine in each direction and in all speeds.
Watch the drum and the wheels.
Starting and stopping operations should be progressive.
The drum and the wheel rotation should be normal at all
Check for noise from the pump and drive motors.
Check for the second of the relief valves that are
opening. The opening pressures of the relief valves are
given in Propel Pump Relief Valve -Test and Adjust and
Charge Relief Valve -Test and Adjust of this module.
After selecting the travel speed of the compactor, the
forward and reverse motion should be identical.
Probable Causes of Problems in the
The propel system engages very slowly when the operator
is attempting to shift.
Low charge pressure.
The orifices in the piston pumps are plugged.
The oil is too viscous and/or the oil is too cold.
The charge filter is plugged.
The hydraulic oil level is low.
The control valve is malfunctioning.