GMC 1986 P-Truck Service Manual page 216

3B3-10 POWER STEERING
Tires for correct air pressure.
Power steering system, replacing parts as
necessary.
Im portant
• All tests are made with the engine idling at
normal operating temperature. Check the idle
adjustment and if necessary adjust the engine
idle speed to the correct specification. Refer to
FUEL SYSTEMS (SEC. 6C).
Test With J-5176-D
1. Place a container under the steering gear or
pump to catch the fluid when disconnecting or
connecting the hoses.
2. With the engine NOT running, disconnect the
pressure hose at the steering gear or power
steering pump and install J-5176-D to both hoses
using adapter fitting J-5176-20. The gage must be
between the shut-off valve and pump. Open the
shut-off valve.
3. Remove the filler cap from the pump reservoir
and check the fluid level. Fill the pump reservoir,
with power steering fluid, to the full mark on the
dipstick. Start the engine and, momentarily
holding steering wheel against stop, check the
connections at J-5176-D for leakage.
4. Bleed the system. Refer to " Bleeding the Power
Steering System."
5. Insert thermometer J-5421-02 in the reservoir
filler opening. Move the steering wheel from stop
to stop several times until the thermometer
indicates that the hydraulic fluid in the reservoir
has reached a temperature of 65° to 77°C (150°
to 170°F).
Figure 6—Tools For Power Steering System Test
Important
• To prevent scrubbing flat spots on the tires,
do not turn the steering wheel more than
five times without rolling the vehicle to
change the tire-to-floor contact area.
6. Start the engine and check the pumps fluid level.
Add power steering fluid if required. When the
engine is at normal operating temperature, the
initial pressure read on the gage (valve open)
should be in the 550-860 kPa (80-125 psi) range.
Should this pressure be in excess of 1380 kPa
(200 psi) — check the hoses for restrictions and
the poppet valve for proper assembly.
NOTICE: Do not leave valve fully closed for
more than 5 seconds as the pump could be
damaged internally.
7. Close the gate valve fully 3 times. Record the
highest pressures attained each time.
• If the pressures recorded are within the
specifications at the end of this section, and
the range of readings is within 345 kPa (50
psi), the pump is functioning within its speci­
fications.
• If the pressures recorded are high, but do
not repeat within 345 kPa (50 psi), the flow
controlling valve is sticking. Remove the
valve, clean it and remove any burrs using
crocus cloth or fine hone. If the system
c o n ta in s som e d irt, flu s h it. If it is
exceptionally dirty, both the pump and gear
must be completely disassembled, cleaned,
flushed and reassembled before further us­
age.
• If the pressures recorded are constant but
more than 690 kPa (100 psi), below the
minimum listed specification, replace the
B-07325