STEERING SENSOR VALVE
3. Plugged spool orifices
Problem No. 2
2. Install two 3000 PSI capacity gauges, one in
each of the ports as shown in the top picture
Extremely fast steering at high engine speed
on page no. 203.
3. Start the engine and warm the hydraulic fluid.
With the engine at low idle. turn the machine
1. Stuck spool
against the steering stops and hold. Both
gauges should read steering relief pressure or
2. Plugged spool orifices
4. Slowly accelerate the engine RPM and observe
Valve shifts at too high of engine RPM
RPM at which the gauge attached to port num-
b e r 2 indicates a drop in pressure to approxi-
mately 100 PSI. If the gauge attached to port
number 2 does not show a pressure drop off at
the specified RPM it will be necessary to adjust
the valve on the steering pump. The 175 shovel
To check for a worn pump:
should bypass at 1600 RPM.
5 . The gauge attached to port number 1 should
1. Install a flow meter in the discharge port of
indicate steering relief pressure. If this pres-
the power sensor valve. The return oil from the
sure is not correct, adjust it first.
flow meter can be routed tot he reservoir. Warm
the hydraulic fluid to 150 F.
6. If the gauge reading, attached to port number 2,
does not drop at the specified RPM, remove the
2 . Accelerate engine speed to maximum and
acorn nut and the lock nut from the adjusting
check the pump flow at 100 PSI or less. Re-
cord the engine speed and the pump GPM.
screw on the valve mounted on the steer pump.
Turn the screw clockwise to increase the RPM
3. Increase the pump pressure to 1500 PSI
at which the gauge drops; turn the screw
with the engine at maximum RPM. Record
counter-clockwise to decrease the RPM a
the pump flow (GPM) and the engine RPM.
which the gauge drops.
7. Tighten the locknut and replace the acorn nut.
4. Flow measured in step 3 must be 80% or more
of the flow measured in step number 2. If it is
Recheck the adjustment to make sure that it has
less than 80% the pump must be replaced.
Problem No. 4
TROUBLESHOOTING THE POWER STEERING
PUMP AND VALVE
Valve shifts at too low of an engine RPM
Remember that the power steering pump and
s e n s o r valve is only one of several components
used in the steering system. Be sure to examine
a l l components when troubleshooting the power
1. Incorrect pilot adjustment
sensor steering valve.
Problem No. 1
2. Orifices in the spool plugged
Slow steering at low engine speed.
When accelerating the engine, the valve shifts
1. Sticking spool
at too high of an engine RPM. When decelerating,
the valve shifts at too low of an engine RPM.
2. Broken spool return spring