Chery A series. Manual — part 79
1 Front wheel hub
7 Bolt
13 Piston damping washer
2 Dust cover
8 Bolt
14 Bracket
3 Brake pad assy.
9 Left caliper housing
15 Lock screw
4 Dust boot
10 Piston
16 Brake disc
5 Guide rod
11 Piston gasket
17 Screw
6 Bleeder valve screw
12 Piston dust cover
Structure of Front Wheel Disc Brake
The rotating component of front brake is the brake disc, which is fixed onto the wheel hub
and rotates together with the hub. The brake caliper bracket is a fixed component (integrated
with the steering knuckle). When braking, the piston pushes the friction pad adjacent to the
piston due to the hydraulic pressure, and makes the pad press the brake disc. Since the brake
caliper moves relatively on the guide rod of caliper bracket, the counterforce will push the
caliper together with friction pad to the other side of brake disc, until the forces applied on
both friction pads are equalized.
The piston gasket installed in the caliper housing is elastically deformed when braking, and
resumes the original shape, based on the elastic restoring force, and makes the piston return
back to its original position when the brake is released. When brake clearance exceeds the set
value due to the wear of friction pad, the piston will slide relatively with the gasket so as to
achieve the automatic adjustment of clearance.
Characteristics of Front Wheel Disc Brake
* Stable braking performance. The disc brake is generally free of the friction adding effect,
so the friction factor makes very limited influence on the braking performance, and the
brake stability of whole vehicle is considerably improved.
* Good water stability, i.e., its efficiency decrease is small after being soaked in water. The
brake lining of disc brake is with high unit pressure which is easy to squeeze out the water,
and, based on the centrifugal force, only the first or twice braking is required to resume the
original after water is squeezed out. And, for the drum brake, tenth braking or more is
required to resume the original.
* Lower possibility of forming the hot crack or hotspot under the high temperature than
that of the brake drum provided that the brake disc is not too thick.
* Smaller dimension and lighter weight than drum brake in case that their output moments
of braking force are the same.
* Extremely low thermal expansion in the thickness direction of brake disc, which isn't the
same as the thermal expansion of brake drum to make the clearance of brake increase
considerably and cause the too larger travel of brake pedal.
* Easy and automatic clearance regulation, and simple maintenance and repair operation.
P-10
DISASSEMBLY/ASSEMBLY AND INSPECTION OF REAR WHEEL DRUM BRAKE
1. Stop dowel
7. Regulating plate
13. Parking braking cable
2. Bolt
8. Push rod
14. Brake shoe assy.
3.
Brake
wheel
cylinder
9.
Regulating
plate
spring
15.
Limit
spring
4.
Brake
back
plate
10.
Brake
shoe
fixing
spring
16. Limit spring seat
5.
Rubber
stop
block
11.
Lower
return
spring
17.
Brake
drum
assy.
6. Shoe plate
12. Return spring
P-11
DISASSEMBLY/ASSEMBLY OF BRAKE SHOE OF REAR WHEEL DRUM BRAKE
Removal:
-- Remove the rear wheel.
-- Insert the turning tool into the tire bolt fastening
hole on the brake drum, press the shoe clearance
regulating wedge-shaped block upwards to make
the brake shoe return back to its original position.
-- Detach the brake drum.
-- Remove the brake shoe fixing spring and parking
braking cable.
-- Unclip the lower limit spring seat of the shoe, and
remove the limit spring.
-- Remove the spring of the regulating
wedge-shaped block (as shown in the right
figure); And take off the return spring, as shown
in the figure.
-- Remove the brake shoe and friction lining assy.
-- It is only allowed to replace the whole brake shoe
and friction lining assy. when replacing.
Installation:
-- Fix up the fixing spring, as shown in the figure.
Install the brake shoe on the push rod, and insert
the regulating wedge-shaped block. And the side
with the convex positioning faces the brake back
plate.
P-12
-- Install the brake shoe and parking brake lever, and
reassemble the return spring, as shown in the
figure.
-- Fix the parking brake cable on the parking brake
lever, and install the brake shoe on the brake
wheel cylinder.
-- Install the lower return spring, and adjust the
return spring and the spring of wedge-shaped
block.
-- Install the brake drum and rear wheel hub bearing.
-- Forcefully step on the brake pedal several times to
make the friction lining of brake in place.
REPLACEMENT OF FRICTION LINING OF BRAKE
-- Check whether there are some oil stains on the
surface of friction lining of brake, and use an
abrasive cloth to grind off it, if any. Replace the
friction lining of drum brake in case it is worn to
its limit, and replace it together with the brake
shoe when replacing.
Caution: The friction lining of brake shall be
from the same manufacturer and with
the same quality when it is replaced
with new one.
INSPECTION OF REAR WHEEL DRUM BRAKE
-- Measure the inner diameter of brake drum, as
shown in the figure.
Standard inner diameter: 200 mm
Service limit: 201 mm
In case there are some scratches and indentions on
the inner circle of brake drum after use, reprocess
the inner circle on a lathe.
Caution: The inner diameter shall not be greater
than the service limit when the inner
circle is reprocessed on the lathe.
P-13
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