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PART
2-1-GENERAL BRAKE SERVICE
2-3
3. If the brake warning lamp
does not light when a pressure
differential condition exists in the
brake system, -the condition may be
caused by:
(a) burnt out warning lamp.
(b) inoperative warning lamp switch.
(c) open circuit in switch to lamp
wiring.
ROAD TEST
The car should be road tested only
if the brakes will safely stop the car.
Apply the brakes at a speed of 25-30
mph to check for the c:xistence of the
trouble symptoms listed in Table 1 ,
Page 2-6 with the exception of those
resolved in the preliminary tests and
brake chatter. For each of the symp-
toms encountered, check and elimin-
ate the causes which are also listed in
Table
1.
To check for brake chatter
or surge apply the brakes lightly
from approximately 50 mph.
If the preliminary tests show that
the booster is inoperative or if a hard
pedal condition still exists after
eliminating the cause of Hard Pedal
B
COMMON ADJUSTMENTS AND REPAIRS
The brake systems of all car models
are designed to permit full stroke of
the master cylinder when the brake
pedal is fully depressed.
No brake pedal clearance adjust-
ment is required or provided for.
With the brake master cylinder outlet
lineS disconnected and the brake
pedal fully
depress~
at approxi-
mately 50 lbs. force, the brake pedal
assembly should not touch the dash
panel if the brake system is correctly
installed.
·
PARKING BRAKE LINKAGE
ADJUSTMENT-
ALL MODELS
Check the parking brake cables
when the brakes are fully reltased.
If the cables are loose, adjust them
as follows:
1.
Fully release the parking brake
handle.
2. Raise the car.
3. Turn the adjustment nut for-
ward against the equalizer until a
moderate drag is felt when turning
rear wheels.
4. Slacken the adjustment until
the rear wheels are just free to rotate.
HYDRAULIC SYSTEM BLEEDING
When any part of the hydraulic
system has been disconnected for
repair or replacement, air may get
into the lines and cause spongy pedal
action. Bleed the hydraulic system
after it
has been properly connected
to be sure that all air is expelled from
the brake cylindel'$ or disc brake
calipers and lines.
The hydraulic system can be bled
manually or with pressure bleeding
equipment.
·
With disc brakes, more pumping
.
of the pedal is required and more
frequent checking of the master
cylinder may be necessary while
bleeding.
On
all vehicles except the G.T. the
warning light switch must be removed
from the master cylinder prior to
bleeding the system or after brake
malfunction; if this is not done the
switch may·be damaged.
MANUAL BLEEDING
The primary and secondary (front
and rear) hY.draulic brake systems are
individual -systems and are bled
separately. Bleed the longest line
first on the individual system being
serviced. During the complete
bleeding
-
operation, DO NOT
allow the reservoir to run
dry.
Keep the master cylinder reservoirs
filled with Motorcraft brake -fluid.
Do not mix low tempera-
ture brake fluids with the
~ci
fied fluid during the bleeding
operations. Never re-use brake
fluid which has been drained
from the hydraulic system.
1.
To bleed the secondary (rear)
brake system, position a suitable
i
in. ring spanner (Fig. 1) on the
bleeder fitting on the brake wheel
cylinder. Attach a rubber drain tube
to the bleeder fitting. The end of the
tube should fit snugly around the
bleeder fitting.
2. Submerge the free end of the
tube in a container partially filled
with clean brake fluid, and loosen the
bleeder fitting approximately
!
of a
turn.
3. Push the brake pedal down
slowly through its full travel. Close
the bleeder fitting, then return the
pedal to the full release position.
Repeat this
operation until air
bubbles cease to appear at the sub-
merged end of the bleeder tube.
4. When the fluid
is completely
free of air bubbles, close the bleeder
fitting and remove the bleeder tube.
listed in Table 2, Page 2-7 the trouble
may be caused by vacuum leakage.
Disconnect the vacuum line at the
booster, remove the vacuum mani-
fold and check valve assembly, and
look for a sticking or faulty check
valve. Check all vacuum connections
for leakage or obstruction. Check all
hoses for a leaking or collapsed con-
dition. Repair or replace parts as
necessary.
If the trouble persists, replace the
vacuum booster. The booster is not a
serviceable item and if found defec-
tive must be replaced.
FIG. 1 - Wrench for Bleeding
Brake Hydraulic System
5. Repeat this procedure at the
brake wheel cylinder on the opposite
side. Refill the master cylinder reser-
voir after each wheel cylinder is bled
and install the master cylinder cover
and gasket. Be sure the diaphragm
type gasket is properly posi-
tioned in the master cylinder
cover. When the bleeding opera-
tion is completed, the fluid level
should
be filled to within
i
ln. of
the top of the reservoirs.
6. If the primary (front brake)
system is to be bled, repeat steps
1-5
at the left front brake caliper or
cylinder and ending at the right front
brake caliper or cylinder.
7. On disc brake equipped models
be sure that the front brake pistons
are returned to their normal positions
and that the pad and lining assem-
blies are properly seated by depress-
ing the brake pedal several times until
normal pedal travel is established.
8~
Replace the warning light
switch.
*G.T.
only.
Centralize the differential
valve (Page 2-4).
PRESSURE BLEEDING
Bleed the longest lines first. The
bleeder tank should contain enough
new Brake Fluid to ·complete the
bleeding operation. Use Motorcraft
Brake Fluid.
Do not mix low temperature brake
fluid with the specified brake fluid
during the bleeding operations. Never
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