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rants are diametrically
opposite
each
other.
FLOW
CONTROL VALVE
Since the pump is a constant dis-
placement
pump,
the internal flow
will vary
directly
with the pump
speed.
However,
a power steering
gear
requires
a relatively
high
con-
stant rate of flow in the
parking
zol!e
and
up
to approximately 2800 RPM
and
thereafter
a lower rate of
flow.
This is
accomplished
by
means
of a
variable orifice
mechanism
shown in
f-ig.
37.
All of the internal pump flow is
ported
from the
pumping mechanism
(rotor, slippers, and cam
insert),
PART 3-3-
POWER
STEERING
through passage
A into the flo\1{ con-
trol
zone.
All of
flow goes
through
the orifice and out into the line until
the bypass
port
is cracked
open:
This
is the regulation point. The oil
drops
in
pressure
in
moving
through
the
orifice. The
lower pressure is then
sensed
through
a hole drilled in the
cover
communicating
to the rear of
the spool
valve.
The
difference
in
pressure
thus created on the spool
.
valve increases steadily and
propor-
tionally with increasing
RPM and
this moves the valve
progressively
back into its bore, thus
increasing
the
openmg
of the bypass port.
.
The
metering
pin
(Fig. 37)
travels
with the
spool
valve
decreasing the
net
area of the orifice
at higher
speeds.
This action reduces flow to
the steering
gear.
EJ
IN-CAR ADJUSTMENTS AND REPAIRS
·
HOISTING INSTRUCTIONS
Damage to suspension
and/
or
steering
linkage components
may oc-
cur if care is
not exercised
when posi-
tioning
the hoist
adapters
of
l
post
hoists prior to
lifting
the car.
If a 2 post
hoist
is used to lift the
car, place the
adapters
under the
front
suspension
lower arms.
Do not
aUow the adapten to contact the
steering linkage,
Pf.lMP BELT TENSION
AD)UsTMENT
Pump drive belt tension cannot
be
checked accurately using the
thumb
pressure or
belt
deflection
methods.
Correct belt
adjustment
is
assured only with the use of a belt
tension
gauge.
1.
Check the
belt tension with a
.
belt tension
gauge
(
8620-.H).
With
a
new
belt, or one
that has been
run for less than
10
minutes,
the ten-
sion should
be
within 120-150 lbs.
With a belt that has been run for
more
than 10
minutes,
the tension
should be within 90-120 lbs.
2.
To adjust the belt, loosen the
mounting
bolts incorporated
on
the
front face of the pump cover plate
(hub side) and one nut at the
rear.
Place a O fto inch open end wrench on
the
projecting
lh inch boss on the
front
face of
the pump cover plate
and pry
upward
to adjust belt tension.
When adjusting the power steering
pump belt tension, do not pry against
the pump or reservoir to obtain the
proper belt
tension.
The reservoir will
be
deformed when pried on or
pressed against and a leak will result.
3.
Recheck
the belt tension. When
the tension has been
correctly
ad-
justed,
torque the bolts and the nut
to specification.
POWER STEERING PUMP
TO
STEERING BOX HOSES AND
TUBES
Removal
1.
Remove the fluid from the
pump reservoir with a suction
gun.
2.
Disconnect
the fluid return
and
pressure
hoses from the
steering
box
and allow to drain into a
pan.
3.
Disconnect
the fluid
return
and
pressure
hoses from the
pump.
4. Raise the car on a hoist.
5.
Remove
the two bolts from the
left hand engine mount and one bolt
from the right hand engine mount
that attach the three tube clamps to
the crossmember.
6.
Lower the tubes, clamps and
insulator
assemblies from the
car.
7.
To remove the clamp and insu-
lator assemblies from the tubes it is
necessary to
compress
the
clamp
and
insulator
slightly
with a pair
of pliers
3-25
PRESSURE RELIEF
VALVE
When the
steering
wheel is turned
completely
to the stop
position
in the
right or left turn
direction,
or in the
case
of
a road load of
sufficient
mag-
nitude, the
steering gear
will not ac-
cept any flow from
the pump,
except
for a very limited volume
of
oil due
to
leakage
past valve seals. Because
of this
resistance,
excessive
hydraulic
pressure
would be developed,
if it
were not limited by the pressure re-
lief valve.
When relief
pressure
is
reached,
the pressure
relief ball
is forced off
its
seat,
allowing
oil to pass
through
the spool valve and dump into
the
bypass
port
(Fig.
37).
The relief valve
will continue
to limit oil
pressure
to
the relief setting for the duration of
the
overload condition.
to release the locking tongue and
while
compressed
lever the two legs
of the
clamp
apart with a screw
driver. The
clamp
and
insulator
may
now be
removed
from the tubes.
Installation
8. Install the retaining clamps and
insulators on the tubes.
When
installed
·
on the
insulators
it is necessary to
compress
the clamp sufficiently to
allow the locking tongue to snap into
place.
N.B. The fluid return hose must be
in the
uppermost position
in the in·
sulators
when
fitted to the
car.
9.
Position
the tube and hose as-
semblies on the
crossmember,
insert
the
attaching
bolts and torque to
specifications.
10. Lower the car.
11.
Connect
the fluid return hose
and
pressure
pipe to the steering
box.
12.
Connect
the fluid return and
pressure
hoses to the pump. Torque
all unions and clamps to specifica·
tions.
13. Fill the pump to the correct
level with
M2C33F Automatic
trans-
mission fluid.
14. Start the engine and turn the
steering
wheel to each end of its
travel several times to cycle the
system.
Then,
check for fluid
leaks.
15.
Stop the
engine
and check the
power
steering
fluid
level.
Add fluid
as
required.
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