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F. If after adjusting the pressure relief screw the pressure does not come up to specification, the
pump may be at fault, repair or replace pump.
NOTE:
If pump is faulty it is also likely the power steering will show signs of low pressure.
2. Fan motor runs continuously.
A. Check for 12 volts at the relief valve solenoid. Solenoid will not operate properly with less than 12
volts.
B. If check shows 12 volts at solenoid, solenoid or solenoid valve may be faulty. Repair or replace
solenoid or solenoid valve.
C. If check shows no voltage at solenoid, check voltage supply at temperature control switch. If check
shows 12 volts at temperature control switch, switch is at fault, replace switch. If check shows no
voltage, check circuit breaker and all connections, short in circuit or open circuit.
3. Fan motor runs under speed.
A. Check engine speed at idle and full RPM.
B. See Steps 1-D, through 1-F.
4. Shaft seal leak on pump is recognized by excessive addition of hydraulic oil, or in the Cummins 5.9T,
and overfilled condition of the engine crankcase. Replace shaft seal or pump. Change engine oil.
COOLING SYSTEM
CAUTION: Use extreme care when removing a radiator pressure-control cap. The sudden release of pres-
sure from a heated cooling system can result in a loss of coolant and possible personal injury (scalding)
from the hot liquid or steam.
Coolant should be drained and replaced every 2 years. See individual Quick Reference Maintenance Chart
for complete guidelines for each engine.
On vehicles used in stop-and-go service, such as the Q-Bus, engine hoses deteriorate more rapidly; there-
fore it is important to inspect all such hoses frequently. Hoses which are worn, chafed, hardened or cracked
must be replaced before a leak develops. On an age hardened hose, retightening a worm screw clamp will not
stop connection leaks, and further indicates that the hose needs replacement. It is also important not to over-
tighten clamps as this can damage the hose, or distort the tubing connector. When replacing a hose, the clamp
should be torqued to 45 inch lbs. When checking a hose clamp, clamps should be torqued to a minimum of 34
inch lbs.
QBRE PITMAN ARM
If it becomes necessary to remove the pitman arm from the steering gear, it is possible with the gear still
on the vehicle. The pitman arm may be removed as follows:
1. Remove the front of the drag rod from the pitman arm.
2. Rotate the steering gear so that the pitman arm nut and bolt are accessible with a socket and extension
for a ratchet wrench.
3. Locate and mark pitman arm and steering gear output shaft with a scribe or felt marker before re-
moval of pitman arm to ensure reinstallation in the same location.
4. After removing the pitman arm nut and bolt, the pitman arm boss must be spread in order to loosen
the pitman arm for removal from the shaft. Spreading the boss may be accomplished by using the
correct size Allen wrench, a chisel or a pitman arm spreader.
