Worm Shaft, Rotary Valve Assembly And Adjuster Plug; Adjust Worm Bearing Preload - Pontiac Grand Prix Service Manual

9-40 1969 PONTIAC SERVICE MANUAL
complaint, a thrust bearing adjustment and over center
(high point) 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 1 114" from rack-pis-
ton nut to thrust bearing face. This* is center (high
point) position.
4. Attach an inch-pound torque wrench with 314"
12-point socket to stub shaft (Fig. 9-75).
5. Oscillate wrench through a total arc of approxi-
mately 1/2 turn left and 1/2 turn right from center
(high point) several times and take a reading. Highest
reading obtained with worm rotating should be 0.5 to
3.0 lb. in. torque with gears from Pontiac Catalina
models without air conditioning and all Tempest and
Firebird models or 1.5-4.5 lb. in. torque on all Pontiac
and Grand Prix models except Pontiac Catalina
models without air conditioning. Record torque when
in specifications.
NOTE: DO NOT use torque wrench having maximum
ue reading of more than 100 lb. in. When taking
torque readings, take a reading pulling torque
wrench to right and a reading pulling 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 bearing adjustment and over center
(high point) 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 riext size smaller
(or larger) balls and recheck.
TABLE OF SELECTIVE SIZES OF
STEERING NUT BALLS
6
.28117" 56955 12
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 7539 against worm end. Turn
worm out of rack-piston assembly following worm end
with arbor. Do not allow arbor to separate from worm
until rack-piston nut is fully on arbor. The arbor now
keeps the balls from dropping out of ball nut.
WORM SHAFT, ROTARY VALVE ASSEMBLY AND
ADJUSTER PLUG
ASSEMBLE
1. Assemble lower thrust bearing and races on worm
(Fig. 9-76).
2. Be sure O-ring seal is between valve body and worm
head and assemble valve assemble to worm by
aligning slot in valve body with pin on worm head.
3. Install new O-ring on adjuster plug.
4
4. Install adjuster plug assembly on stub shaft so
bearing rests against upper bearing assembly.
ADJUST WORM 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 increases
0.5-2.0 lb. in. above drag reading obtained in step 3
above with gears from Pontiac Catalina models
without air conditioning and all Tempest and Firebird
models or 1;O-3.0 lb. in. torque on all Pontiac and
Grand Prix models except Pontiac Catalina models
without
air
conditioning.
NOTE: Do not use torque wrench having maximum
torque reading of more than 100 lb. in. When taking
following torque readings, take reading pulling torque
wrench to right and a reading pulling 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 lb. ft.
torque.
6. Recheck thrust bearing preload. Total thrust bearing