Power Steering Gear And Pump - Pontiac TRANS AM 1977 Service Manual

POWER STEERING GEAR AND PUMP 3B3-1
SECTION 383
POWER STEERING GEAR AND PUMP
C AUTl 0 N
: All Steering gear fasteners are important attaching parts in that they could affmt the performance of vital
parts 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 i f replacement becomes necessary. Do not use a replacement part of lesser quality or substitute
design. Torque values must be used as specified during reassembly to assure proper retention of these parts.
CONTENTS OF THIS SECTION
General Description
..................................................................................................
3B3-1
Power Steering Gear
..........................................................................................
3B3-1
Power Steering Pump
.......................................................................................
3B3-2
Service Procedures
...................................................................................................
3B3-3
Pitman Shaft Seals
..............................................................................................
3B3-3
Steering Gear
........................................................................................................
3B3-4
Adjuster Plug Assembly
...................................................................................
3B3-5
Valve and Stub Shaft Assembly
.......................................................................
3B3-7
Pitman Shaft and Side Cover
...............................................................................
3B3-10
Rack-Piston
...........................................................................................................
3 ~ 3 - 1 0
Steering Gear Hose Connector
.........................................................................
3B3-1 1
Poppet Check Valve
....................................................................................
3B3-1 1
Pitman Shaft Needle Bearing and Seals
.........................................................
3 ~ 3 - 1 2
Adjustment
............................................................................................................
3B3-13
Power Steering Gear Ball Plug
............................................................................
3 ~ 3 - 1 7
Pump Belt
.............................................................................................................
3B3-1 7
..............................................................................................
Flow Control Valve 3B3-18
Pump Shaft Oil Seal
.............................................................................................
3B3-19
Power Steering Pump
...........................................................................................
3B3-20
Bleeding Power Steering System
..........................................................................
3B3-25
605 Power Steering Gear
.....................................................................................
3B3-35
Specifications
...........................................................................................................
3B3-39
GENERAL DESCRIPTION
POWER STEERING GEAR
The major internal components of the variable ratio
steering gear (Fig. 3B3-1) are the rotary valve assembly,
steering worm, rack-piston assembly and the pitman shaft.
The movement of these parts, while turning or parking, is
aided by hydraulic pressure supplied by the pump. Manual
steering is always available at times when the engine is not
running, or in the event of pump or belt failure. Steering effort
is increased under such conditions.
The steering stub shaft rotary valve, worm shaft, and
rack-piston assembly are all "in line". The rack-piston in the
variable ratio steering gear is modified to accomodate the
larger center tooth on the pitman shaft gear. All oil passages
are internal within the gear housing, except for the pressure
an-d return hoses between the gear and the pump.
The mechanical element of this steering gear is a low-
friction, recirculating ball system in which steel balls act as
a rolling thread between the steering worm and the rack-
piston. The one piece rack-piston assembly is geared to the
sector of the pitman shaft.
The hydraulic rotary valve is concentric with the input
shaft and is contained in the upper section of the gear
housing. It contains a spool that is held in neutral position
by means of a torsion bar and the valve body into the other
end. Twistine of the torsion bar allows the s ~ o o l to rotate in
relation to t i e valve body, thereby operatin; the valve (Fig.
3B3- 1).
Under normal driving conditions the steering wheel
effort will range from 1 to 1-1/2 pounds and parking effort
will range from 2 to 2-1/2 pounds.
B Series models with firm ride option use a straight 14: 1
ratio gear. All other models use a variable ratio (l6:l to 13:l)
power steering gear.
A production code is stamped on the gear side cover for
identification purposes.