Chevrolet 1988 Light Duty Truck Repair Manual page 115

The following notice applies to one or more steps in the assem bly procedure of com ponents in this portion of the
manual as indicated at appropriate locations by the term inology " NOTICE: Refer to Notice on page 3B3-1 of this S ection."
NOTICE: A ll s te e rin g fa ste n e rs are im p o rta n t a tta c h in g p a rt in th a t it c o u ld a ffe c t the p e rfo rm a n c e o f vita l c o m p o ­
n e n ts a n d system s, a n d /o r c o u ld re s u lt in m a jo r re p a ir expe n se . They m u s t be re p la c e d w ith o n e o f th e sam e p a rt
n u m b e r o r w ith an e q u iv a le n t p a rt i f re p la c e m e n t b e c o m e s necessary. Do n o t use a re p la c e m e n t p a rt o f le sser
q u a lity o r s u b s titu te d e sig n. T orque values m u s t be u se d as s p e c ifie d d u rin g re a sse m b ly to assure p ro p e r re te n tio n
o f th is part.
SUBJECT
D escrip tion ........................................................................................................................................................ j...............................3 B 3 - 1
Saginaw Integral Power Steering Gear- RV, G, P, ST, M ................................................................................................3 B 3 - 3
D isassem b ly..................................................................................................................................................................................3 B 3 - 3
Cleaning and In s p e c tio n .......................................................................................................................................................... 3 B 3 - 5
A s s e m b ly ...................................................................................................................................................................................... 3 B 3 -
Saginaw Integral Power Steering Gear- CK (GMT 4 0 0 ) .................................................................................................. 3 B 3 - 9
Saginaw Power Steering Pum p- Model T C ..........................................................................................................................3 B 3 -1 5
D isassem b ly..................................................................................................................................................................................3 B 3 -1 5
Cleaning and In s p e c tio n .......................................................................................................................................................... 3 B 3 -1 5
A s s e m b ly ...................................................................................................................................................................................... 3 B 3 -1 5
Saginaw Power Steering Pump Model P ................................................................................................................................3 B 3 -1 9
D isassem b ly..................................................................................................................................................................................3 B 3 -1 9
Cleaning and In s p e c tio n .......................................................................................................................................................... 3 B 3 -1 9
A s s e m b ly ...................................................................................................................................................................................... 3 B 3 -2 0
Saginaw Power Steering Pump Model C B ............................................................................................................................ 3 B 3 -2 0
Com ponent R e p a ir.....................................................................................................................................
Hydraulic Pump A s s e m b ly ......................................................................................................................................................3 B 3 -2 2
S p e c ific a tio n s ..................................................................................................................................................................................3 B 3 -2 4
Special T o o ls .................................................................................................................................................................................... 3 B 3 -2 5
The hydraulic power steering system consists of a
pump, an oil reservoir, a steering gear, a pressure hose,
and a return hose.
The steering gear is made by Saginaw Division, Gen­
eral Motors. The steering gear is identified by a large S
cast into the side of the housing. A building date is
stamped in the cover. The building date is a four digit
number. The first three digits are the Julian day of the
year. The remaining digit is the last digit of the year.
The power steering pump is made by Saginaw Division,
General Motors.
The power steering gear (figure 1) has a recirculating
ball system which acts as a rolling thread between the
worm shaft and the rack piston. The wormshaft is sup­
ported by a thrust bearing preload and two conical thrust
races at the lower end, and a bearing assembly in the
adjuster plug at the upper end. When the wormshaft is
turned right, the rack piston moves up in gear. Turning the
wormshaft left moves the rack piston down in gear. The
rack piston teeth mesh with the sector, which is part of the
pitman shaft. Turning the w orm shaft turns the pitman
shaft, which turns the wheels through the steering link­
age.
SECTION 3B3
POWER STEERING
CONTENTS
DESCRIPTION
POWER STEERING 3B3-1
The control valve in the steering gear directs the power
steering fluid to either side of the rack piston. The rack
piston converts the hydraulic pressure into a mechanical
force. If the steering system becomes damaged and loses
hydraulic pressure, the vehicle can be controlled m anu­
ally.
The hydraulic pump is a vane-type design. There are
two types, submerged and nonsubmerged. Submerged
pump (P models) have a housing and internal parts that
are inside the reservoir and operate submerged in oil. The
nonsubmerged pump (TC models with or w ithout reser­
voir) function the same as the submerged pump except
that the reservoir is separate from the housing and inter­
nal parts.
There are two bore openings at the rear of the pump
housing. The larger opening contains the cam ring, pres­
sure plate, thrust plate, rotor and vane assembly, and end
plate. The smaller opening contains the pressure line
union, flow control valve, and spring. The flow control ori­
fice is part of the pressure line union. The pressure relief
valve inside the flow control valve limits the pump pres­
sure.
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6
............................ 3 B 3 -2 0>