PART
3-4
POWER STEERING
Section
Page Section Page
1 Description
............................
.3-20 3 Removal and Installation
.................
.3-22
.................
2 In-Car Adjustments and Repairs
...........
.3-22
4
Major Repair Operations
.3-23
DESCRIPTION
Master-Guide Power Steering (Fig.
steering wheel movement, directs the
and fluid in the left end of the cylin-
1) is a hydraulically controlled link- pressure developed by the pump. der returns to the reservoir (Fig. 2).
age-type steering system which in-
cludes a fluid reservoir and pump, a
control valve, a power cylinder, the
connecting fluid lines, and the steer-
ing linkage. The roll-type hydraulic
pump, belt-driven from the engine
crankshaft, draws fluid from the res-
ervoir and provides fluid pressure
for the system. Within the pump it-
self is a pressure-relief valve which
governs the pressures within the
steering
-
system according to the
varying conditions of operation.
After fluid has passed from the pump
to the control valve and the power
cylinder, it returns to the reservoir.
When the front wheels are in the
straight-ahead position, the control
valve spool is held in the center
(neutral) position by its centering
spring. Fluid then flows around the
valve lands and returns to the reser-
voir (Fig. 2). Within the control
valve
body there is a reaction limit-
ing valve which reduces parking
effort.
When force of about
4
pounds is
exerted for a left turn, the valve
spool overcomes the pressure of the
centering spring and moves toward
the right end of the valve. As a re-
sult, pressure is exerted on the right
If the direction of the force on
the steering wheel is reversed, the
front wheels will return to the
straight forward position. Or as force
on the steering wheel falls below ap-
proximately
4
pounds the valve spool
centering spring forces the spool
back to the center position and there
the pressure on both sides. of the
power cylinder piston is equal. With
normal forward driving movement of
the car and in the absence of oper-
ative pressure within the power
cylinder, the front wheels will seek
to return to the straight ahead posi-
tion. This is a normal effect of the
The control valve, operated by side of the power cylinder piston, front wheel alignment.
For a right turn, the directional
forces explained above are reversed
(Fig. 2).
If, for any reason, the pump fails
to deliver fluid pressure, the car may
be steered without pump pressure.
An engine idle speed control device
(Fig. 3) eliminates the problem of
the engine stalling when the driver
parks the car. When the steering
spindle arm stops are contacted, the
output of the pump becomes maxi-
mum and the maximum pressure is
directed to the control valve.
The maximum pressure causes the
plunger of the control valve to move
the bellcrank linkage; thus, the prop-
er engine idle speed is maintained.
Refer to the engine specification sec-
1233-A
tion of this manual for the proper
FIG.
1
-Power Steering System
engine idle speeds.
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