Pontiac tempest 1968 Service Manual page 594

S T E E R I N G 9-37
5. Oscillate wrench through a total arc of approxi­
mately 60 degrees In both directions several times
and take a reading. Highest reading obtained with
worm rotating should be 0.5 to 3.0 in, lb
0
torque with
gears from Tempest, Firebird and Pontiac Catalina
models without air conditioning and 1.5-4.5 in
0
lb.
torque on all other Pontiac models. Record torque
when in specifications.
NOTE: DO NOT use torque wrench having max™
imum torque reading of more than 100 in. lb. When
taking following torque readings, take a reading,
pulling torque wrench to right and a reading, pull­
ing torque wrench to left. Total both readings and
take one-half of this total as average torque.
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. If balls were pitted or rough then
select proper ball size for proper adjustment.
6. If reading is too high or low (on new balls only),
disassemble and reassemble, using next size smaller
(or larger) balls and re check.
Table of Selective Sizes of
Steering Nut Balls
6
.28117" 5695512
7 .28125" 5695513
8 .28133" 5695514
9 .28141" 5695515
10
.28149" 5695516
11 .28157" 5695517
4. Install adjuster plug assembly on stub shaft so
bearing rests against upper bearing assembly.
ADJUST THRUST BEARING PRELOAD
1. Install worm valve assembly and adjuster plug
In housing as integral unit.
2. Tighten adjuster plug snug In gear housing and
back off slightly (1/8 turn maximum).
3. With torque wrench on stub shaft, read torque
required to rotate worm, valve assembly, and stub
shaft in housing (drag).
4. Turn adjuster plug in until torque reading in­
creases 0.5-2.0 in. lb. above drag reading obtained
in (3) above with gears from Tempest, Firebird, and
Pontiac Catalina models without air conditioning and
1.0-3.0 in. lb. torque on all other Pontiac models.
NOTE: Do not use torque wrench having maxi­
mum torque reading of more than 100 lb. in. When
taking following torque readings, take reading,
pulling torque wrench to right, and a reading, pull­
ing torque wrench to left. Total both readings and
take one-half of this total as average torque.
5. Install adjuster plug lock nut and tighten to 80
ft. lb. torque.
6. Recheck thrust bearing preload. Total thrust
bearing adjustment plus drag should not exceed 7.0
in. lb. torque with gears from Tempest, Firebird
and Pontiac Catalina models without air conditioning
and 8.0 in. lb. with all other Pontiac models.
A rack-piston nut with a ball size of 7 does not
have a number stamped on flat surface,, For ball
sizes other than No. 7, ball size is stamped on flat
surface of rack-piston nut. In order to obtain proper
worm bearing preload install proper new balls.
7. Remove rotary valve assembly from worm
head.
8. Position arbor tool J 7639 against worm end.
Turn worm out of rack-piston assembly following
worm end with arbor. Do not allow arbor to sepa­
rate from worm until rack-piston nut is fully on ar­
bor. The arbor now keeps the balls from dropping
out of ball nut.
ASSEMBLE WORM SHAFT, ROTARY VALVE ASSEMBLY
AND ADJUSTER PLUG AS AN ASSEMBLY
1. Assemble lower thrust bearing and races on
worm (Fig. 9-67).
2. Be sure O - ring seal is between valve body and
worm head and assemble valve assembly to worm by
aligning slot in valve body with pin on worm head.
REPLACE RACK-PISTON
1. Slip stub shaft flexible coupling onto end of
stub shaft.
2. Holding Teflon ring compressor sleeve tool
J 8947 or J 7576 tightly against the shoulder of gear
housing, insert the rack-piston nut and arbor into
housing holding the arbor (tool J 7539) until arbor
contacts worm end. See Fig. 9-68. Use tool J 8947
/ R O T A R Y V A L V E A S S E M B L Y
~ T O R S I O N B A R C A P
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T Q W O R M
o
R I N G
T H R U S T B E A R I N G
S T E E R I N G W O R M "
T H R U S T B E A R I N G R A C E S *
3. Install new O-ring on adjuster plug.
F i g . 9-67 Exploded View of Worm Shaft and Rotary Valve