Cadillac 60 Series 1963 Shop Manual page 61

5-2
POWER STEERING
GEAR DESIGN
Stub Shaft
7
Rotary Valve ^1
Pitman Shaft < ^ ? F
Gear JT
Pitman Shaft
Piston
Worm
^ Shaft
\
Housing
Fig. 5-3 Steering Gear Cut-Away View
The major components of the steering gear are
the rotary valve assembly, steering worm, rack-
piston assembly, and the pitman shaft, Fig. 5-3.
The movement of these parts, while turning or
parking, is aided by hydraulic fluid supplied by
the pump. Manual steering, however, is always
available at times when the engine is not running,
or in the event of pump failure. Steering effort is
increased under such conditions.
The steering input shaft, hydraulic valve, worn>
shaft, and rack-piston assembly are all "in line".
All oil passages are internal within the gear hous-
ing, except for the pressure and return hoses be-
tween 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 sec-
tion of the gear housing. It contains a spool that
is held in neutral position by means of a torsion
bar. The spool is attached to one end of the tor-
sion bar. and the valve body to the other end.
Twisting of the torsion bar allows the spool to
rotate in relation to the valve body, thereby oper-
ating the valve.
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.
PUMP DESIGN
The major components of the power steering
pump are the oil reservoir, drive shaft, pump
housing, pump ring, pressure plate, thrust plate,
flow control valve, and rotor and vane assembly,
Fig. 5-4. The pump housing and component parts
are encased in the oil reservoir with only the
mounting face and shaft hub exposed. A filler cap
with a dipstick is integral with the oil reservoir.