Maverick and Comet Repair
Maverick and Comet Brakes
BRAKE SYSTEM
Self-adjusting, internal expanding duo-servo drum brakes are standard equipment
on all 1970-75 Maverick and Comets. Sliding caliper front disc brakes are
available as optional equipment on 1974-75 models and standard on 1976-77
models. Power assist is used on disc brake models.
DRUM BRAKES
Drum brakes on all Mavericks and Comets employ single-anchor,
internal-expanding, and self-adjusting brake assemblies. The automatic adjuster
continuously maintains correct operating clearance between the linings and the
drums by adjusting the brake in small increments in direct proportion to lining
wear. When applying the brakes while backing up, the linings tend to follow the
rotating drum counterclockwise, thus forcing the upper end of the primary shoe
against the anchor pin. Simultaneously, the wheel cylinder pushes the upper end
of the secondary shoe and cable guide outward, away from the anchor pin. This
movement of the secondary shoe causes the cable to pull the adjusting lever
upward and against the end of the tooth on the adjusting screw starwheel. As
lining wear increases, the upward travel of the adjusting lever also increases.
When the linings have worn sufficiently to allow the lever to move upward far
enough, it passes over the end of the tooth and engages it. Upon release of the
brakes, the adjusting spring pulls the adjuster lever downward, turning the
star-wheel and expanding the brakes.
INSPECTION
1. Raise the front or rear of the car and support the car with safety stands.
Make sure that the parking brake is not on.
2. If you are going to check the rear brakes, remove the lug nuts that attach
the wheels to the axle shaft and remove the tires and wheels from the car. Using
a pair of pliers, remove the tinnerman nuts from the wheel studs. Pull the brake
drum off the axle shaft. If the brakes are adjusted too tightly to remove the
drum, see Step 4. If you can remove the drum, see Step 5.
3. If you are going to check the front brakes, then the front tire, wheel and
brake drum can be removed as an assembly. Remove the hub cap, then either pry
the dust cover off the spindle with a screwdriver or pull it off with a pair of
channel-lock pliers. Remove the cotter pin from the spindle. Slide the nut lock
off the adjusting nut, then loosen the adjusting nut until it reaches the end of
the spindle. Do not remove the adjusting nut yet. Grab the tire and pull it out
toward yourself, then push it back into position. This will free the outer wheel
bearing from the drum hub. If the brakes are adjusted up too tightly to allow
the drum to be pulled off them, go to Step 4 and loosen up the brakes, then
return here. Remove the adjusting nut, washer and outer bearing from the
spindle. Pull the tire, wheel, and brake drum off the spindle.
4. If the brakes are too tight to remove the drum, get under the car (make sure
that you have safety stands under the car to support it) and remove the rubber
plug from the bottom of the brake backing plate. Shine a flashlight into the
slot in the plate. You will see the top of the adjusting screw starwheel and the
adjusting lever for the automatic brake adjusting mechanism. To back off on the
adjusting screw, you must first insert a small, thin screwdriver or a piece of
firm wire (coat-hanger wire) into the adjusting slot and push the adjusting
lever away from the adjusting screw. Then, insert a brake adjusting spoon into
the slot and engage the top of the star-wheel. Lift up on the bottom of the
adjustment spoon to force the adjusting screw star-wheel downward. Repeat this
operation until the brake drum is free of the brake shoes and can be pulled off.
5. Clean the brake shoes and the inside of the brake drum. There must be at
least 1/16 in. of brake lining above the heads of the brake shoe attaching
rivets. The lining should not be cracked or contaminated with grease or brake
fluid. If there is grease or brake fluid on the lining, it must be replaced and
the source of the leak must be found and corrected. Brake fluid on the lining
means leaking wheel cylinders. Grease on the brake lining means a leaking grease
retainer (front wheels) or axle seal (rear brakes). If the lining is slightly
glazed but otherwise in good condition, it can be cleaned up with medium
sandpaper. Lift up the bottom of the wheel cylinder boots and inspect the ends
of the wheel cylinders. A small amount of fluid in the end of the cylinders
should be considered normal. If fluid runs out of the cylinder when the boots
are lifted, however, the wheel cylinder must be rebuilt or replaced. Examine the
inside of the brake drum; it should have a smooth, dull finish. If excessive
brake shoe wear caused grooves to wear in the drum it must be machined or
replaced. If the inside of the drum is slightly glazed, but otherwise good, it
can be cleaned up with medium sandpaper.
6. If no repairs are required, install the drum and wheel. If the brake
adjustment was changed to remove the drum, adjust the brakes until the drum will
just fit over the brakes. After the wheel is installed it will be necessary to
complete the adjustment. See "Brake Adjustment" later in this chapter. If a
front wheel was removed, tighten the wheel bearing adjustment nut to 17-25 ft.
lbs. while rotating the wheel. This will seat the bearing. Loosen the adjusting
nut 1/2 turn, then retighten it to 10-15 ft. lbs.
BRAKE DRUM REMOVAL AND INSTALLATION
See Steps 3 and 4 under "Drum Brakes Inspection."
BRAKE SHOE REMOVAL AND INSTALLATION
NOTE: If you are not thoroughly familiar with the procedures involved in
brake replacement, only disassemble and assemble one side at a time, leaving the
other wheel intact as a reference.
1. Remove the brake drum. See the inspection procedure.
2. Place the hollow end of a brake spring service tool (available at auto parts
stores) on the brake shoe anchor pin and twist it to disengage one of the brake
retracting springs. Repeat this operation to remove the other spring
CAUTION: Be careful the springs do not slip off the tool during removal, as
they could cause personal injury.
3. Reach behind the brake backing plate and place a finger on the end of one of
the brake hold-down spring mounting pins. Using a pair of pliers, grasp the
washer on the top of the hold-down spring that corresponds to the pin that you
are holding. Push down on the pliers and turn them 90° to align the slot in the
washer with the head on the spring mounting pin. Remove the spring and washer
and repeat this operation on the hold- down spring on the other brake shoe.
4. Place the tip of a screwdriver on the top of the brake adjusting screw and
move the screwdriver upward to lift up on the brake adjusting lever. When there
is enough slack in the automatic adjuster cable, disconnect the loop on the top
of the cable from the anchor. Grasp the top of each brake shoe and move it
outward to disengage it from the wheel cylinder (and parking brake link on rear
wheels). When the brake shoes are clear, lift them from the backing plate. Twist
the shoes slightly and the automatic adjuster assembly will disassemble itself.
5. If you are working on rear brakes, grasp the end of the brake cable spring
with a pair of pliers and, using the brake lever as a fulcrum, pull the end of
the spring away from the lever. Disengage the cable from the brake lever.
6. The brake shoes are installed as follows: If you are working on the rear
brakes, the brake cable must be connected to the secondary brake shoe before the
shoe is in¬ stalled on the backing plate. To do this, first transfer the parking
brake lever from the old secondary shoe to the new one. This is accomplished by
spreading the bottom of the horseshoe clip and disengaging the lever. Position
the lever on the new secondary shoe and install the spring washer and the
horseshoe clip. Close the bottom of the clip after installing it. Grasp the
metal tip of the parking brake cable with a pair of pliers. Position a pair of
side cutter pliers on the end of the cable coil spring and, using the pliers as
a fulcrum, pull the coil spring back with the side cutters. Position the cable
in the parking brake lever.
7. Apply a light coating of high-temperature grease to the brake shoe contact
points on the backing plate. Position the primary brake shoe on the front of the
backing plate and install the hold-down spring and washer over the mounting pin.
Install the secondary shoe on the rear of the backing plate.
8. If working on the rear brakes, install the parking brake link between the
notch in the primary brake shoe and the notch in the parking brake lever.
9. Install the automatic adjuster cable loop end on the anchor pin. Make sure
that the crimped side of the loop faces the backing plate.
10. Install the return spring in the primary brake shoe and, using the tapered
end of a brake spring service tool, slide the top of
the spring onto the anchor pin.
CAUTION: Be careful to make sure that the spring does not slip off the tool
during installation, as it could cause injury.
11. Install the automatic adjuster cable guide in the secondary brake shoe,
making sure that the flared hole in the cable guide is
inside the hole in the brake shoe. Fit the cable into the groove in the top of
the cable guide.
12. Install the secondary shoe return spring through the hole in the cable guide
and the brake shoe. Using the brake spring tool, slide the top of the spring
onto the anchor pin.
13. Clean the threads on the adjusting screw and apply a light coating of
high-temperature grease to the threads. Screw the adjuster closed, then open it
one-half turn.
14. Install the adjusting screw between the brake shoes with the starwheel
nearest to the secondary shoe. Make sure that the star-wheel is in a position
that is accessible from the adjusting slot in the backing plate.
15. Install the short hooked end of the automatic adjuster spring in the proper
hole in the primary brake shoe.
16. Connect the hooked end of the automatic adjuster cable and the free end of
the automatic adjuster spring in the slot in the top of the automatic adjuster
lever.
17. Pull the automatic adjuster lever (the lever will pull the cable and spring
with it) downward and to the left and engage the pivot hook of the lever in the
hole in the secondary brake shoe.
18. Check the entire brake assembly to make sure everything is installed
properly. Make sure that the shoes engage the wheel cylinder properly and are
flush on the anchor pin. Make sure that the automatic adjuster cable is flush on
the anchor pin and in the slot on the back of the cable guide. Make sure that
the adjusting lever rests on the adjusting screw starwheel. Pull upward on the
adjusting cable until the adjusting lever is free of the starwheel, then release
the cable. The adjusting lever should snap back into place on the adjusting
screw starwheel and turn the wheel one tooth.
19. Expand the brake adjusting screw until the brake drum will just fit over the
brake shoes.
20. Install the wheel and drum and adjust the brakes. See "Brake Adjustment."
DRUM BRAKE ADJUSTMENT
NOTE: Drum, brakes installed in Mavericks and Comets are self-adjusting. All
that is normally required to adjust the brakes is to apply them moderately hard
several times while carefully backing the car in Reverse. However, if this
action proves unsatisfactory, or if it proves necessary to re-adjust the brakes
after replacing the linings or removing the drum, the following procedure may be
used.
1. Raise the car and support it with safety stands.
2. Remove the rubber plug from the adjusting slot on the backing plate.
3. Insert a brake adjusting spoon into the slot and engage the lowest possible
tooth on the starwheel. Move the end of the brake spoon downward to move the
starwheel upward and expand the adjusting screw. Repeat this operation until the
brakes lock the wheel.
4. Insert a small screwdriver or piece of firm wire (coat-hanger wire) into the
adjusting slot and push the automatic adjuster lever out and free of the
starwheel on the adjusting screw.
5. Holding the adjusting lever out of the way, engage the topmost tooth possible
on the starwheel with a brake adjusting spoon. Move the end of the adjusting
spoon upward to move the adjusting screw starwheel downward and contract the
adjusting screw. Back off the adjusting screw starwheel until the wheel spins
freely with a minimum of drag. Keep track of the number of turns the star- wheel
is backed off.
6. Repeat this operation for the other side. When backing off the brakes on the
other side, the adjusting lever must be backed off the same number of turns to
prevent side-to-side brake pull.
7. Repeat this operation on the other set of brakes (front or rear).
8. When all 4 brakes are adjusted, make several stops, while backing the car, to
equalize all of the wheels.
9. Road-test the car.