GMC 1989 Light Duty Truck, Repair Manual, Page: 120 / 998

3B3-6 POWER STEERING
— Sealing and bearing surfaces of the pitman
shaft ( 221 ) for roughness, nicks, or other dam ­
age. Replace the pitman shaft assembly if nec­
essary.
— Pitman shaft (221) for excessive wear or scor­
ing. C heck the se ctor gear teeth fo r w ear.
Replace the pitman shaft assembly if neces­
sary.
— Adjuster screw (222) threads for wear. The
adjuster screw must be free to turn with no end
play.
2. Rack piston.
— Worm (248) and rack piston (214) grooves and
all balls (213) for scoring. BOTH M UST BE
REPLACED as a matched assembly.
— Seal (216) and ring (217) for wear.
— Ball return guide halves (212) for cracks and
damaged.
— Bearing (247) and races (246) for scoring and
excessive wear.
— Rack piston (214) teeth and external ground
surfaces for scoring or excessive wear. If either
condition exists, replace the rack piston (214)
and worm (248).
3. Adjuster plug.
— Spacer (235) for wear or cracks.
— Races (236, 238) for wear or scoring.
— Adjuster plug (240) threads for wear.
— Bearing (237) for wear or scoring.
— Needle bearing (241) for wear, pitting or scor­
ing. Replace if necessary.
4. Valve and stub shaft.
— Seals (231) and rings (232).
— Shaft pin for wear or cracks. If excessively worn
or broken, replace the com plete valve and shaft
assembly.
— Ground surface of the stub shaft (251). If a cro­
cus cloth ca nn ot clean the nicks or burrs,
replace the entire valve assembly.
— Outside diam eter of the valve spool and inside
diam eter of the valve body (250). If a crocus
cloth cannot clean the nicks or burrs, replace
the entire shaft and valve assembly.
— The small notch in the skirt of the valve for wear.
If worn replace the com plete valve assembly.
— Valve spool inside the valve body (250). The
valve spool, when lubricated with steering fluid,
must rotate freely w ithout binding. If binding
occurs, replace the com plete valve and shaft
assembly.
ASSEMBLY
■►4* install or Connect (Figures 1 ,4 , and 10 through 14)
Tools Required
J 4245 Snap Ring Pliers
J 6217 Valve C onnector
J 21552 Ball Retainer
J 22407 Bearing Installer
J 8092 Bearing Driver
J 7079 Bearing Remover and Installer
J 8524-1 Driver
J 7624 Bearing Preload Spanner W rench
1 . Balls (213), alternately by color, in the rack piston
(214) (figure 1 2). Use J 21552 in the rack piston.
• Lubricate the 24 balls with power steering fluid.
2. Balls (213), alternating by color, in the ball guide (212)
(figure 13).
• Retain the balls in the guide with petroleum
jelly.
A. In s ta ll B a lls In T h is H o le W h ile S lo w ly
R o ta tin g W o rm C o u n te rc lo c k w is e
B. W orm F la n g e
2 U
R ack p js to n
210. S cre w
211. C la m p
212. Ball G u id e s
213. B a lls
B-06517
F ig u re 1 2 — Installing th e Balls into th e R ack P iston
Figure 1 3 — R etain in g th e B alls in th e Ball G uide