Gear Service Adjustments - GMC T Series 1994 Repair Manual

GEAR SERVICE ADJUSTMENTS

Tools Required:
J 7754-01 Torque Wrench
NOTICE:
Repair the steering gear in a clean, dust-free
location. Use clean tools and equipment. Dirt or grit will
damage the machined surfaces and result in leaking, or
damage to the steering gear assembly.
Do not adjust with the steering gear installed in the vehicle.
It is difficult to properly adjust the preload while taking
torque readings through the steering column. Take the
time to make the adjustments properly, with the gear
removed from the vehicle.
Adjust
Inspect
Front end alignment.
Drag link adjustment.
Tire pressure.
Place a container under the steering gear or pump to
1.
catch fluid when disconnecting or connecting the
power steering lines. Remove the gear from the
vehicle.
• Disconnect drag link from the pitman arm.
• Disconnect steering coupling from the gear.
• Disconnect power steering lines at the gear.
• Remove four bolts that attach the gear to the
gear support.
2. Place the gear in a vise.
9
Important
Be sure to clamp the gear using soft jaws.
Clamp only on the mounting pads. Clamp­
ing the steering gear elsewhere can affect
your preload readings and cause gear dam­
age.
3. Drain the oil from the gear by rotating the gear
through its complete travel several times.
4. Center the steering gear by turning the stub shaft
from the right wheel stop to the left wheel stop while
counting the number of turns. Rotate the stub shaft
back half the of number turns to center position.
5. Use torque wrench J 7754-01 and a deepwell
3/4" 12 pt. socket. Check the total preload torque by
rotating through a 180° arc either side of center.
Take the reading while turning back over the center
position. Record the highest reading.
6. Turn stub shaft one half turn (180°) right or left from
center. Install torque wrench vertical on stub shaft.
Turn torque wrench 20° left or right of vertical.
Take torque reading while turning torque wrench
back to vertical. Subtract this reading from reading
taken in step 5. If the reading in step 5 is 0.23 N*m
(2 lb. in.), then the gear is adjusted properly. Go to
step 7. If less than 0.23 N*m (2 lb. in.), proceed with
the following adjustments.
• If the reading in step 5 is at least 0.23 N*m
(2 lb. in.) and not more than 1.13 N*m
(10 lb. in.), the gear is in proper adjustment.
Proceed with adjustment in step 7.
• If the reading in step 5 is less than 0.23 N*m
(2 lb. in.) or more than 1.13 N*m (101b. in.),
proceed with adjustment in steps 7 and 8.
7. With the gear on center, loosen adjuster plug lock
nut. Using spanner wrench J 7624, turn the adjuster
plug in (clockwise) until firmly bottomed in the
housing (approximately 20 lb. ft.).
Mark the housing even with one of the holes
in the adjuster plug.
M easure back in a counterclockw ise
direction 1/2 inch (approximately 20°) and
make a second mark on the housing.
Rotate adjuster plug counterclockwise until
hole in adjuster is in line with second mark.
Tighten lock nut. Make sure adjuster plug
does not move while lock nut is tightened.
Turn the stub shaft two turns right or left from
center. With the torque wrench installed on
the stub shaft near vertical, take the torque
reading. The torque reading should be
0.56-1.13 N#m(5-10 lb. in.) while turning
the torque wrench in an arc 20° left or right of
vertical.
8. With the gear on center, loosen the pitman shaft
adjuster lock nut. Make sure the adjusting screw is
backed out counterclockwise all the way. Turn the
adjuster screw clockwise 1/2 turn. This prevents the
pitman shaft from bottoming out in the side cover.
• Check preload by putting the torque wrench
vertical. Then move 90° left or right of
center. The torque reading should be the
highest reading taken while turning the torque
wrench back to center. Record the reading.
• Tighten the adjuster screw clockwise until
the torque wrench reading is 0.68-1.13 N*m
(6-10 lb. in.) higher than the reading taken in
previous step.
• Tighten the lock nut to 90 N*m (66 lb. ft.). Be
sure the adjuster screw does not turn.
• Recheck the preload after tightening
the locknut.
9. Reinstall steering gear in vehicle.