Pontiac tempest 1968 Service Manual page 593

9-36
1968 P O N T I A C S E R V I C E M A N U A L
Fig. 9-64 Loading Rack Piston Nut
5, Insert guides into guide holes of rack-piston
nut. Guides should fit loosely.
6. Place return guide clamp over guides and in­
stall two screw and lock washer assemblies and
tighten to 10 ft. lb
0
torque.
CHECK WORM PRELOAD
The worm groove is ground with a high point in
the center. When the rack-piston nut passes over
this high point, a preload of 0 . 5 - 3
o
0 in
a
lb
0
torque
should be obtained with gears from Catalina models
without air conditioning and all Tempest Firebird
models and 1 . 5 - 4
0
5 in
Q
lb
0
torque on all other Pontiac
models.
lips are properly positioned* retaining ring is seated,
and
that approximately 1 / 1 6 " clearance is main­
tained between inner seal (single lip) and bearing,
4. If connectors were removed, install new con­
nectors by driving into place with tool J 6217 (Fig.
9 - 6 3 ) .
ASSEMBLE RACK-PISTON NUT AND WORM
1. Lubricate and install new ring back-up seal and
Teflon piston ring on rack-piston nut being careful
ring and seal do not twist during installation.
2. Insert worm into rack-piston nut to bearing
shoulder (Fig. 9 - 6 4 ) .
3. Align ball return guide holes with worm groove.
Load 15 balls into the guide hole nearest Teflon
piston ring. While slowly rotating worm to left, feed
balls through the circuit. Alternate black balls with
silver balls. If balls are installed properly, worm
should turn out of rack-piston nut.
4. F i l l one-half of ball return guide with remain­
ing 7 balls. Place other guide over balls and plug
each end with heavy grease to prevent balls from
falling out when installing guides into rack-piston
nut (Fig. 9 - 6 5 ) .
G R E A S E
B A L L R E T U R N G U I D E
NOTE: DO NOT refit rack-piston balls unless a
complaint of loose steering is received. Upon such
a complaint, a thrust adjustment and over center
adjustment should correct problem if it lies in
steering gear.
1. With worm pointing up, lightly clamp rack-
piston nut in a bench vise having brass jaws.
CAUTION: Do not hold rack-piston nut in area of
Teflon ring.
2. Place valve assembly on worm, engaging worm
drive pin.
3. Rotate worm until it extends 1 1 / 4 " from rack-
piston nut to thrust bearing face. This is center
position.
4. Attach an inch-pound torque wrench with 3 / 4 "
12-point socket to stub shaft (Fig. 9 - 6 6 ) .
"T
J 6 4 5 9
F i g . 9-65 Bali Return G u i d e
F i g . 9-66 Checking Worm Preload