Buick LeSabre 1965 Service Manual page 475

STEERING GEAR
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STEERING COLUMNS AND LINKAGE
POWER STEERING 8 - 1 1
RACK-PISTON NUT
BACK-UP
O-RING
VALVE BODY
WORM
CHECK
VALVE
ADJUSTER
PLUG
LOWER
THRUST
BEARING
UPPER
THRUST
BEARING
GEAR HOUSING
SNAP RING
PITMAN SHAFT
Worm shaft radial l o a d s are
transmitted to the gear housing
through the rack-piston nut. Worm
end thrust is c a u s e d by the
tendency of the worm to thread
itself into or out of the rack-
piston nut as the steering wheel is
turned right or left. This end
thrust is absorbed entirely by the
upper and lower thrust bearings.
The upper thrust bearing is lo-
cated between the valve body and
adjuster plug and the lower thrust
bearing is located between the
housing and upper end of worm.
The upper steering shaft is a
separate shaft supported in the
steering column jacket. Its upper
Figure 8-14—Power Steering Gear
end is supported by a bearing and
its lower end by an adapter and
ball bearing assembly.
The steering shaft is connected to
the power steering gear through a
flexible coupling which is riveted
to the steering shaft flange. This
flexible c o u p l i n g helps absorb
minor shocks and vibrations, and
dampens out hydraulic noises
from the gear assembly and the
steering column jacket assembly.
The power steering gear identifi-
cation number is stamped on the
gear housing side cover. The
first 3 digits show the day of the
year (1 through 365) the gear was
tested. The last digit shows the
year (5 for 1965 etc.)
c. Rotary Valve Assembly
The rotary valve assembly con-
trols the flow of oil from the
pump to the proper side of the
rack-piston nut when power as-
sistance is required and cuts off
this flow when power assistance
is not required.
The rotary valve assembly is lo-
cated in the upper section of the
gear housing and consists of a
stub shaft, a torsion bar, a valve
body, a valve spool and a valve
body cap. See Figure 8-15. The