Drum Brakes - Ford Comet 1965 Shop Manual

P A R T 2-1-GENERAL BRAKE SERVICE
2-7
blies installed, insert a feeler gauge
between the lining and rotor. If the
clearance is not within 0.002-0.010-
inch, check for shoe and lining as-
semblies not being properly seated
on the caliper bridges, for a piston
pushed back in the cylinder bore, for
a seized piston, or for malfunction
of a piston seal.
Ordinarily, the clearance should
be 0.002-0.010-inch. However, if
the vehicle was stopped by a brake
application just prior to checking
the clearance, the brakes may drag
slightly.
4. To check rotor runout, first
eliminate the wheel bearing end play
by tightening the adjusting nut. After
tightening the nut check to see that
the rotor can still be rotated.
5. Clamp a dial indicator to the
caliper housing so that the stylus
contacts the rotor at a point approxi-
mately 1-inch from the outer edge.
Rotate the rotor and take an indica-
tor reading. If the reading exceeds
0.002-inch total indicator runout, re-
place the rotor. Do not attempt to
refinish a rotor that indicates runout
in excess of specification. When the
runout check is finished be sure to
adjust the bearings as outlined in
Group 3, in order to prevent bear-
ing failure.
6. Check the rotor for scoring.
Minor scores can be removed with
a fine emery cloth. If the rotor is
excessively scored, replace it.
7. Visually check the caliper. If it
is cracked or if excess leakage is evi-
dent, it should be replaced. Slight
leakage or seized pistons indicate re-
moval and disassembly.
8. If upon disassembly the caliper
is found to be distorted or damaged,
or if the cylinder bores are scored
or excessively worn, replace the as-
sembly.
The two halves of the caliper as-
sembly should never be separated.
Damage or failure of one requires
replacement of both as a unit.
DRUM BRAKES
1. Remove the wheel from the
drum, and remove the drum as out-
lined in Part 2-2, Section 2. Wash
all the parts except the brake shoes
in a cleaning fluid and dry with com-
pressed air.
2. Brush all dust from the carrier
plate and interior of the brake drum.
3. Inspect the brake shoes for ex-
cessive lining wear or shoe damage.
If the lining is worn to within 1/32-
inch of the rivet heads or if the
shoes are damaged, they must be re-
placed. Replace any lining that has
been oil saturated. Replace the lin-
ing in axle sets. Prior to replacement
of the lining, the drum diameter
should be checked to determine if
oversize linings must be installed.
4. Check the condition of the
brake shoes, retracting springs, and
drum for signs of overheating. If the
shoes have a slight blue coloring, or
if the springs show a change in free
length, indicating overheating, re-
placement of the retracting and hold
down springs is necessary. Over-
heated springs lose their pull and
could cause the new lining to wear
prematurely if they are not replaced.
5. If the car has 30,000 or more
miles of operation on the brake lin-
ings, or signs of overheating are
present when relining brakes, the
wheel cylinders should be disassem-
bled and inspected for wear and dirt
in the cylinder. The cylinder cups
and other parts contained in the
overhaul kit should be replaced, thus
avoiding future problems.
6. Inspect all other brake parts
and replace any that are worn or
damaged.
7. Inspect the brake drums and,
if necessary, refinish. Refer to Part
2-2, Section 4 for refinishing.
BOOSTER UNIT—COMET
A disassembled view of the brake
booster is shown in Fig. 41, Part 2-2.
After disassembly, immerse all
metal parts in cleaning solvent.
Clean the plastic parts in alcohol
only, taking care to avoid chipping
or damage. Replace all rubber parts.
Use an air hose to blow out dirt and
cleaning solvent from recesses and
internal passages. When overhauling
a vacuum booster, use all parts fur-
nished in the repair kit.
BOOSTER UNIT—FAIRLANE
A disassembled view of the brake
booster is shown in Fig. 50, Part 2-2.
After disassembly, immerse all
metal parts in a suitable solvent.
Use only alcohol on rubber parts or
parts containing rubber. After the
parts have been thoroughly cleaned
and rinsed in cleaning solvent, the
metal parts which come in contact
with hydraulic brake fluid or rubber
parts should be rewashed in clean
alcohol before assembly. Use an air
hose to blow dirt and cleaning fluid
from the recesses and internal pas-
sages. When overhauling a power
booster, use all parts furnished in
the repair kit. Discard all old rub-
ber parts.
Inspect all other parts for damage
or excessive wear. Replace damaged
or excessively worn parts. If the
inside of the booster body is rusted
or corroded, polish it with steel wool
or fine emery cloth.