Ford Thunderbird 1967 - Part 3-3: Steering

3-18
PART
3-3-
Steering
Section
Page
1
Description
and
Operation
3-18
S tee
ring
Gear
3.
1
g
Power
Steering
Pump
3-20
2
In-Vehicle
Adjustments and
Repairs
3-20
Valve
Spool
Centering
Check
3-20
Steering
Gear
Adjustments
3-21
Pump
Belt
Tension
Adjustment
3-21
Power
Steering
Pump
Drive
Belt
Replacement
3-21
3
Removal
and
Installation
3-21
Steering
Gear
3-21
Section
Page
Power
Steering Pump
3-22
Vehicles
Without
Air
Conditioner
3-22
Vehicles With Air
Conditioners
3-22
Power
Steering
Pump
Pulley
3-22
Power
Steering
Pump
Reservoir
3-23
4
Major
Repair Operations
3-23
Steering
Gear
3-23
Valve
Centering
Shim
Replacement
3-23
Steering
Gear
Disassembly
3-25
Parts Repair or
Replacement
3-26
Steering
Gear
Assembly
3-27
DESCRIPTION AND
OPERATION
STEERING GEAR
DESCRIPTION
The power
steering
unit (Fig.
1)
is
a torsion-bar type
of
hydraulic
as
sisted
system.
This system
furnishes
power
to
reduce the amount of
turn
ing
effort required at the
steering
wheel.
It
also
reduces road shock and
vibrations.
The torsion bar power
steering
unit
includes
a
worm and one-piece rack
piston,
which
is meshed
to
the
gear
teeth on the
steering
sector shaft.
The
unit also
includes a
hydraulic
valve,
valve
actuator,
input shaft and tor
sion
bar
assembly
which are
mounted
on the
end
of
the
worm shaft and
op
erated
by
the
twisting
action of the
torsion bar.
The
torsion-bar
type of
power
steering
gear
is designed
with the one
piece
rack-piston,
worm and
sector
shaft in one
housing
and
the valve
spool in an
attaching
housing
(Fig.
1).
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
between the
pump
and
gear
assembly.
The
power
cylinder
is an
integral
part of
the
gear housing.
The
piston
is
double
acting,
in
that
fluid
pres
sure
may
be
applied
to
either side of
the
piston.
A
selective
metal
shim,
located
in
the
valve
housing
of
the
gear
is for
the
purpose of
tailoring
steering
gear
efforts.
If
efforts are
not
within
specifi
cations
they
can
be
changed
by
in
creasing
or
decreasing
shim
thickness
as
follows:
Efforts
heavy
to
the
left
-Increase
shim
thickness.
Efforts
light
to
the
left
Decrease
shim
thickness.
INPUT SHAFT
OUTLET PORT
INLET
PORT
SECTOR
SHAFT COVER
CONTROL VALVE HOUSING
MOUNTING PADS
SECTOR
SHAFT
FIG. 1
Power
Steering
Gear
A
change of
one shim size
will in
crease
or decrease
steering
efforts
ap
proximately
1
1/2
in-lbs.
Shims
are available in the
follow
ing
thicknesses
and
are notched on the
outside
diameter for identification.
0.0057-0.0063
inch
0 notch
0.0077-0.0083
inch
1
notch
0.0097-0.0103
inch
2 notches
0.0117-0.0123
inch
3 notches
0.0137-0.0143
inch-
4
notches
Do
not
use
more
than
one
shim.
The
operation
of the hydraulic
con
trol
valve
spool
is governed
by
the
G1276-A
tvnsting
of a
torsion
bar. All
effort
applied
to the
steering
wheel is
trans
mitted
directly
through the
input
shaft
and
torsion bar
to the worm
assembly
and
integral
piston.
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 as
sist is
required.
The
upper
end
of
the
torsion
bar