GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 48
BRAKES
BASIC OPERATING PRINCIPLES
Hydraulic systems are used to actuate t he brakes of all modern automobiles.
The system transports the power required to force the frictional surfaces of the
braking system together from the pedal to the individual brake units at each
wheel. A hydraulic system is used for two reasons.
First, fluid under pressure can be carried to all parts of an automobile by small
pipes and flexible hoses without taking up a significant amount of room or
posing routing problems.
Second, a great mechanical advantage can be given to the brake pedal end of
the system, and the foot pressure requi red to actuate the brakes can be
reduced by making the surface area of t he master cylinder pistons smaller than
that of any of the pistons in t he wheel cylinders or calipers.
The master cylinder consists of a flui d reservoir along with a double cylinder
and piston assembly. Double type master cylinders are designed to separate
the front and rear braking systems hydraulic ally in case of a leak. The master
cylinder coverts mechanical motion from t he pedal into hydraulic pressure within
the lines. This pressure is translated back into mechanical motion at th\
e wheels
by either the wheel cylinder (drum brak es) or the caliper (disc brakes).
Steel lines carry the brake fluid to a po int on the vehicle's frame near each of
the vehicle's wheels. The fluid is then ca rried to the calipers and wheel cylinders
by flexible tubes in order to allow for suspension and steering movements.
In drum brake systems, each wheel cylinde r contains two pistons, one at either
end, which push outward in opposite direct ions and force the brake shoe into
contact with the drum.
In disc brake systems, the cylinders ar e part of the calipers. At least one
cylinder in each caliper is used to fo rce the brake pads against the disc.
All pistons employ some type of seal, us ually made of rubber, to minimize fluid
leakage. A rubber dust boot seals the outer end of the cylinder against dust and
dirt. The boot fits around the outer end of the piston on disc brake calipers, and
around the brake actuating rod on wheel cylinders.
The hydraulic system operates as follows : When at rest, the entire system, from
the piston(s) in the master cylinder to t hose in the wheel cylinders or calipers, is
full of brake fluid. Upon app lication of the brake pedal, fluid trapped in front of
the master cylinder piston(s) is forced through the lines to the wheel cylinders.
Here, it forces the pistons outward, in the case of drum brakes, and inward
toward the disc, in the case of disc brakes. The motion of the pistons is
opposed by return springs mounted outside the cylinders in drum brakes, and
by spring seals, in disc brakes.
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 50
DISC BRAKES
Instead of the traditional ex
panding brakes that press out ward against a circular
drum, disc brake systems utilize a disc (rotor) with brake pads positioned on
either side of it. An easily-seen analog y is the hand brake arrangement on a
bicycle. The pads squeeze onto the rim of the bike wheel, slowing its motion.
Automobile disc brakes use the identical principle but apply the braking effort to
a separate disc instead of the wheel.
The disc (rotor) is a casting, usually eq uipped with cooling fins between the two
braking surfaces. This enables air to ci rculate between the braking surfaces
making them less sensitive to heat bui ldup and more resistant to fade. Dirt and
water do not drastically affect braking ac tion since contaminants are thrown off
by the centrifugal action of the rotor or scraped off the by the pads. Also, the
equal clamping action of the two brake pad s tends to ensure uniform, straight
line stops. Disc brakes are inherently se lf-adjusting. There are three general
types of disc brake:
1. A fixed caliper.
2. A floating caliper.
3. A sliding caliper.
The fixed caliper design uses two pistons mounted on either side of the rotor (in
each side of the caliper). The caliper is mounted rigidly and does not move.
The sliding and floating designs are quite similar. In fact, these two types are
often lumped together. In both designs, the pad on the inside of the rotor is
moved into contact with the rotor by hy draulic force. The caliper, which is not
held in a fixed position, moves slightly, bringing the outside pad into contact with
the rotor. There are various methods of attaching floating calipers. Some pivot
at the bottom or top, and some slide on mounting bolts. In any event, the end
result is the same.
DRUM BRAKES
Drum brakes employ two brake shoes mounted on a st ationary backing plate.
These shoes are positioned inside a circul ar drum which rotates with the wheel
assembly. The shoes are held in place by springs. This allows them to slide
toward the drums (when they are applied) while keeping the linings and drums
in alignment. The shoes are actuated by a wheel cylinder which is mounted at
the top of the backing plat e. When the brakes are app lied, hydraulic pressure
forces the wheel cylinder's actuating links outward. Since these links bear
directly against the top of the brake s hoes, the tops of the shoes are then forced
against the inner side of the drum. This action forces the bottoms of the two
shoes to contact the brake drum by rotati ng the entire assembly slightly (known
as servo action). When pressure within the wheel cylinder is relaxed, return
springs pull the shoes back away from the drum.
Most modern drum brakes are designed to self-adjust themselves during
application when the vehicle is moving in reverse. This motion causes both
GM – CAMARO 1982-1992 – Repair Guide (Checked by WxMax) 337
7. Use a suitable tool to remove the pinion seal.
To install: 8. Inspect the sealing surfaces of the pinion yoke for nicks or damage and
replace, as necessary. Examine the carrier bore and remove any burrs
that may cause leaks around the outside of the seal.
Fig. 3: Seal installation
9. Install the seal using a suitable installer.
10. Apply a seal lubricant to the outer diameter of the pinion flange and the
sealing lip of the new seal.
11. Install the pinion yoke on the drive pinion by taping with a soft-face
hammer until a few pinion threads project through the pinion yoke.
12. Install the washer an d pinion flange nut. While hol ding the pinion yoke,
tighten the nut to the same positi on as marked earlier, then tighten an
additional
1/16 in. (1.6mm) turn beyond the marks.
13. Install the driveshaft.
14. Install the rear wheels and tires. Check and add the correct lubricant, as
necessary.
BORG-WARNER REAR AXLE 1. Raise and safely support the vehicle.
2. Remove both rear wheel and tire assemblies.
3. Matchmark the driveshaft and pinion yoke so they may be reassembled
in the same position. Remove the driveshaft.
4. Using a beam-type inch pound to rque wrench on the pinion yoke nut,
measure and record the amount of pi nion bearing, axle bearings and