Description - GMC 1986 P-Truck Service Manual

MANUAL STEERING GEAR
The following notice applies to one or more steps in the assembly procedure of components in this portion of the
manual as indicated at appropriate locations by the terminology " NOTICE: See 'Notice' on page 3B2-1 of this
Section."
NOTICE: These fasteners are important attaching parts in that they could affect the performance of vital
components and systems, and/or could result in major repair expense. They must be replaced with one of
the same part number or with an equivalent part if replacement becomes necessary. Do not use a replace­
ment part of lesser quality or substitute design. Torque values must be used as specified during reassembly
to assure proper retention of these parts.
SUBJECT
Description .................................................................................................................................................................3B2- 1
Diagnosis Of Manual Steering System ................................................................................................................ 3B2- 2
On-Vehicle S e r v ic e ................................................................................................................................................. 3B2- 3
M a in te n a n ce ..........................................................................................................................................................3B2- 3
Steering Gear Replacem ent................................................................................................................................3B2- 3
Pitman Shaft Seal R e p lace m e n t....................................................................................................................... 3B2- 4
Steering Gear A d ju s tm e n ts ................................................................................................................................3B2- 5
Steering Gear High Point C e n te rin g .................................................................................................................3B2- 6
S pe cifica tio ns............................................................................................................................................................ 3B2- 7
Special T o o ls ............................................................................................................................................................3B2- 7
The steering gear is the recirculating ball nut and
worm type. The worm is located on the lower end of
the steering shaft. The ball nut is mounted on the worm
and the steel balls act as a rolling thread between the
worm and nut to provide a low friction drive between
them.
Teeth on the ball nut engage teeth on the pitman
shaft sector. The teeth on the ball nut are made so that
a tighter fit exists between the ball nut and pitman
shaft sector teeth when the front wheels are in the
straight ahead position. The sector teeth are slightly
tapered so that a proper preload may be obtained by
moving the pitman shaft endways by means of a pre­
load adjuster screw which extends through the gear
housing side cover. The head of the preload adjuster
and a selectively fitted shim fit snugly into a T-slot in
the end of the pitman shaft, so that the screw also
controls the end play of the shaft (figure 1).
SECTION 3B2
CONTENTS

DESCRIPTION

1. Ball Nut
2. Worm Bearing
3. Seal
4. Wormshaft
5. Balls and Guides
6. Adjuster Plug
7. Nut
8. Worm Bearing (Lower)
9. Pitman Shaft Sector
Figure 1-Manual Steering Gear
3B2-1
PAGE
B-07349