GMC 4000 Series Service Manual page 509

Sec. 9B
Page 498
POWER STEERING
cylinder in tight; then back off to nearest cotter
pin hole and install new cotter pin.
3. Turn front wheels from extreme right to
extreme left and check to see that power cylinder
does not bottom, preventing stops from hitting
the axle.
4. Connect hydraulic hoses to power cylinder
ports. Tighten hose fittings to 25-40 foot-pounds
torque.
NOTE: Make certain hoses are not kinked and
do not bind when wheels are turned.
5. Bleed the hydraulic system and bring fluid
to proper level as previously directed.
POWER CYLINDER SEAL
REPLACEMENT
REMOVAL (Fig. 8)
NOTE: The piston rod seal, wiper ring and
retainer, socket end ball stud seats, and adjuster
screws are the only parts of the power cylinder
that can be replaced.
1. If not previously removed, remove cotter
pin, adjuster screw, and ball seats from one end
of the power cylinder. Use a wide blade screw ­
driver to turn adjuster screw out. Repeat these
procedures at opposite end of the cylinder.
2. Loosen clamp bolt on the outside of the
socket.
3. Using a wide bl^de screwdriver to keep
the piston from turning, unthread socket end from
piston rod.
4. Force piston rod in and out of power cyl­
inder to drain remaining fluid.
5. Using Tru-Arc snap ring pliers, remove
the scraper retainer snap ring from groove in
piston rod guide assem bly.
6. Apply air pressure to the retraction port
G M C S E R V I C E M A N U A L
in the guide assembly while at the same time hold­
ing a finger over the extension port (fig. 8). This
will dislodge wiper ring assembly, scraper retain­
er, scraper retainer O-ring seal, and piston rod
seal from the guide assembly
CLEANING AND INSPECTION
ing solvent and compressed air. Replace all parts
that are not in first class condition.
ASSEMBLY (Refer to Fig. 8)
thin layer of Lubriplate or equivalent, and insert
it into the guide assembly with the "U" of the cup
toward the bottom of opening in guide.
"U" side pointing out.
Tru-Arc snap ring pliers, install the retaining
snap ring. Make sure retaining ring is well seated
in groove of the guide assembly.
rod until it shoulders against the rod.
ball seats; then thread the adjuster screw s into the
sockets loosely.
AXLE MOUNTED CYLINDER
cylinders are shown in figure 9.
against wheel stop.
Figure 9 — A xle M o u n te d Pow er Cylinder Adjustment
Clean and inspect the components using clean­
1. Lubricate lip of the piston rod seal with a
2. Install scraper retainer O-ring seal.
3. Install the scraper retainer in guide with
4. Insert the wiper ring assembly; then using
5. Thread the socket end assembly on piston
6. Tighten the clamp bolt securely.
7. At both ends of the power cylinder, install
POWER CYLINDER ADJUSTMENT
Adjustment dimensions for all axle mounted
1. Attach power cylinder to axle.
2. Position wheels in full right-hand turn,
3. Depress power cylinder piston rod into