Chery A15. Manual - part 79

Maintenance of brake caliper assy.

*  Check the crack and deformation of the brake caliper, and correct or replace it as

appropriate.

*   Check the breakage and crack of the dust boot of piston, and replace the boot, if any.

*   Check the aging, crack and other defectives of the sealing ring of piston, and replace the

ring, if any.

*   Check the oil leakage, motion blocked, unsmooth return of the piston, and repair it, if

any. Check the damage, corrosion and other defectives of the piston and cylinder wall, and
replace the brake caliper assy., if any.

EXPLOSION CHART AND STRUCTURAL CHARACTERISTICS OF FRONT
WHEEL DISC BRAKE

The front wheel disc brake adopts the single-cylinder floating caliper structure in where the
brake caliper body may slide in the axial direction relatively to the brake disc, the structure
of which is shown in the figure below.

Front Wheel Disc Brake

P-9

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