Pontiac FIREBIRD 1972 Service Manual page 1175

9-22 1972 PONTIAC SERVICE MANUAL
the jet pump principle. By reduction of velocity, velocity
energy is converted into supercharge pressure in cavity
(6). During this straight ahead driving condition, the dis-
charge pressure (pressure line) should not exceed 100 p.s.i.
CORNERING AGAINST WHEEL STOPS
When the steering gear control valve is actuated in either
direction to the point of cut-off, the flow of oil from the
pump is blocked. This condition occurs when the front
wheels meet the wheel stop, or when the wheel movement
is otherwise blocked by a curb or deep sand or mud. In
order to keep pressures and temperatures at a minimum,
the pump is equipped with a pressure relief valve. The
relief valve is contained inside the flow control plunger
(13). When the pressure exceeds a predetermined pres-
sure, (greater than maximum system requirements) the
pressure relief ball (14) opens, allowing a small amount of
oil to flow into the bypass hole (5). This flow of oil passing
through the pressure relief orifice (1 1) causes a pressure
drop and resulting lower pressure on the bottom end of the
control valve (9).
The pressure unbalance then causes the valve to compress
the spring (10) allowing the major portion of the oil to
bypass into the intake chamber (from 3 to 6) in the same
manner as is accomplished by flow controlling. Relief
pressures are limited between 900 and 1450 p.s.i. depend-
ing on the vehicle requirements.
STEERING WHEEL
GENERAL INFORMATION
The steering system consists of a steering wheel, steering
column, universal joint (except X Series), intermediate
steering shaft (except X Series), flexible coupling, manual
or power steering gear and steering linkage.
On B, A, G and F Series, the steering linkage is positioned
ahead of the front frame crossmember in accordance with
the steering gear location ahead of the front wheels. The
X Series steering gear and linkage is located behind the
front wheels. The steering knuckle arm is part of the
integral steering knuckle and brake caliper support on B
and F Series, therefore, refer to procedure outlined in
Section 3, Front Suspension, under STEERING
KNUCKLE AND/OR STEERING KNUCKLE ARM
(B & F SERIES)
-
REMOVE AND INSTALL when
servicing.
The intermediate steering shaft and universal joint are
used in conjunction with the steering gear location ahead
of the front wheels. On the F Series, the steering column
toe plate is welded to the column mast jacket.
If it becomes necessary to tow a car with the column
locked and the key is not available, a dolly should be
placed under the rear wheels and the car towed with the
front end raised. If a dolly is not available, tow the car by
lifting the rear end, providing the front wheels are locked
in essentially the straight ahead position (the use of a
steering clamp should be continued for this type of tow-
ing).
MINOR SERVICE
REMOVE
1. Remove screws attaching trim cover to wheel or on
sport type wheel, remove horn button by lifting
(Fig.9-20).
2. Remove nut from shaft.
3. Remove steering wheel using puller J 3044-1.
CAUTION: Do not hammer on end of steering
shaft, as hammering could steering shaft or oth-
erwise loosen plastic injections which maintain
column rigidity.
4. Disconnect horn wire insulator from canceling cam
tower by rotating insulator counter-clockwise to un-
lock position and then pull up.
INSTALL
CAUTION: See CAUTION on page I of this
Section regarding the fastener referred to in
step I .
1. Install by reversing above steps, making sure steering
wheel is in straight ahead position (Fig. 9-21).
Tighten steering wheel nut to 30 lb. ft. torque.
TURN SIGNAL SWITCH
REMOVE
1. Remove steering wheel (see STEERING WHEEL
-
REMOVE).
2. Remove the three cover screws and lift cover off the
shaft.