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(039)
PART
3-3
STEERING
3-15
Section
Page
1 Description and Operation ................. 3-15
2 In-Car Adjustments and Repairs ............ 3-17
3 Removal and Installation .................. 3-20
4 Major Repair Operations .................. 3-21
II
DESCRIPTION AND OPERATION
FIG.
1-Power Steering System
POWER STEERING SYSTEM
The power steering system includes
the crankshaft-driven pump, the tor-
sion bar type steering gear, a fluid
reservoir, pressure and return lines,
and the steering linkage (Fig. 1).
The basic pump consists of a hous-
ing and cover, a rotor and rollers
wHich rotate within a cam ring, and
a pressure plate. A flow control valve
in the pump housing governs the flow
of fluid. Maximum pump pressure is
controlled by a relief valve inside
the flow control valve.
The major details of the power
steering gear are the sector shaft,
ball nut and worm shaft, torsion bar
and control valve, and the power
cylinder and piston. These details all
are contained within a one-piece
housing.
The movement of the control valve
depends upon the twisting of the
torsion bar. The resistance of the
front wheels to being turned governs
the amount of torsion bar twist. As
the torsion bar twiqs, the control
valve moves to direct fluid under
pressure in the side of the piston
which requires power assist.
The
windshield
wiper
svstcrn
HYDRO-WIPE
---r-i
ASSEMBLY
obtains its operating oil pressure
f;·u;n the
rpw,:·
steering hydraulic
·;v<-.tc-ln.
TORSION BAR STEERING GEAR
The
power steering unit is
a
torsion-bar type of hydraulic
assisH~d
system. This system furnishes power
to reduce the amount of turning
effort required at the steering wheel.
It
also reduces road shock and vibra-
tions.
The torsion bar power steering
unit includes a rack and piston, and
a worm and ball nut assembly which
is meshed to the gear on the steering
sector shaft. The unit also includes
a hydraulic valve, valve sleeve, and
torsion
bar
assembly
which
are
mounted on the end of the worm
shaft and operated by the twisting
action of the torsion bar.
The torsion-bar type of power
steering gear is designed with all
components in one housing (Fig. 2).
This makes possible internal fluid
passages between the valve and cyl-
inder. thus eliminating all external
lines and hoses, except the pressure
and return hoses hetween the pump
and gear assembly.
EAR
G1198-A
The power cylinder is an integral
part of the gear housing. This piston
is double acting, in that fluid pres-
sure may be applied to either side of
the piston. The one-piece piston and
power rack is meshed to the sector
shaft.
The operation of the hydraulic
control valve is governed by the
twisting of .a torsion bar. All effort
applied to the steering wheel is trans-
mitted directly through the torsion
bar to the ball nut and worm assem-
bly. Any resistance to the turning of
the front wheels results in twisting
of the bar. The twisting of the bar
increases as the front wheel turning
effort increases. The control valve
spool, actuated by the twisting of
the torsion bar, directs fluid to the
side of the piston where hydraulic
assist is required.
The lower end of the torsion bar
is splined to the lower end of the
inside diameter of the worm shaft.
The upper end of the worm shaft is
coarsely splined to the inside diam-
eter of the torsion bar and input
shaft
assembly
upper
end.
This
spline fit is sufficiently loose so that
the upper end of the torsion har
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