Daewoo Matiz (2003 year). Manual - part 125

4A – 2 HYDRAULIC BRAKES

DESCRIPTION AND OPERATION

WARNING LAMP OPERATION

This brake system uses a BRAKE warning lamp located
in the instrument panel cluster. When the ignition switch
is in the III position, the BRAKE warning lamp should il-
luminate. It should go off when the ignition switch return
to II position. The following conditions will activate the
BRAKE warning lamp.

The lamp should be on whenever the parking brake
applied and the ignition switch is in the II position.

A low fluid level in the master cylinder will turn the
BRAKE warning lamp on.

D17A007A

HYDRAULIC BRAKES 4A – 3

COMPONENT LOCATOR

BRAKE SYSTEM (NON–ABS)

(Left–Hand Drive Shown, Right–Hand Drive Similar)

MAB4A001

1. Power Booster
2. Power Booster Boot
3. Cotter Pin
4. Clevis
5. Clevis Pin
6. Packing
7. Spacer
8. Master Cylinder Assembly
9. Fluid Reservoir Assembly

10. Reservoir Cap

11. Reservoir

12. Grommet Seal
13. Master Cylinder
14. Proportioning Valve
15. Stoplamp Switch
16. Brake Pedal Assembly
17. Clutch Pedal Spring

18. Pedal Bracket Assembly
19. Clutch Pedal Pad
20. Clutch Pedal
21. Cushion
22. Bushing
23. Retaining Ring
24. Spring
25. Brake Pedal Pad
26. Brake Pedal
27. Brake Pedal Spring
28. Accelator Pedal Pad
29. Accelator Pedal
30. Rear Drum Brake Hose
31. E Ring
32. Front Disc Brake Hose
33. Brake Hose Coupling Bolt
34. Plain Washer

4A – 4 HYDRAULIC BRAKES

DIAGNOSITIC INFORMATION AND PROCEDURES

BRAKE SYSTEM TESTING

(Left–Hand Drive Shown, Right–Hand
Drive Similar)

Brakes should be tested on a dry, clean, reasonably
smooth and level roadway. A true test of brake perfor-
mance cannot be made if the roadway is wet, greasy, or
covered with loose dirt whereby all tires do not grip the
road equally. Testing will also be adversely affected if the
roadway is crowned so as to throw the weight so roughly
that the wheels tend to bounce.

Test the brakes at different vehicle speeds with both light
and heavy pedal pressure; however, avoid locking the
brakes and sliding the tires. Locked brakes and sliding
tires do not indicate brake efficiency since heavily
braked, but turning, wheels will stop the vehicle in less
distance than locked brakes. More tire-to-road friction is
present with a heavily braked, turning tire than with a
sliding tire.

Because of the high deceleration capability, a firmer
pedal may be felt at higher deceleration levels.

There are three major external conditions that affect
brake performance:

Tires having unequal contact and grip of the road will
cause unequal braking. Tires must be equally in-
flated, and the tread pattern of the right and the left
tires must be approximately equal.

Unequal loading of the vehicle can affect the brake
performance since the most heavily loaded wheels
require more braking power, and thus more braking
effort, than the others.

Misalignment of the wheels, particularly conditions of
excessive camber and caster, will cause the brakes
to pull to one side.

To check for brake fluid leaks, hold constant foot pres-
sure on the pedal with the engine running at idle and the
shift lever in NEUTRAL. If the pedal gradually falls away
with the constant pressure, the hydraulic system may be
leaking. Perform a visual check to confirm any sus-
pected leaks.

Check the master cylinder fluid level. While a slight drop
in the reservoir level results from normal lining wear, an
abnormally low level indicates a leak in the system. The
hydraulic system may be leaking either internally or ex-
ternally. Refer to the procedure below to check the mas-
ter cylinder. Also, the system may appear to pass this
test while still having a slight leak. If the fluid level is nor-
mal, check the vacuum booster pushrod length. If an in-
correct pushrod length is found, adjust or replace the
rod.

Check the master cylinder using the following proce-
dure:

Check for a cracked master cylinder casting or brake
fluid leaking around the master cylinder. Leaks are in-
dicated only if there is at least one drop of fluid. A
damp condition is not abnormal.

Check for a binding pedal linkage and for an incorrect
pushrod length. If both of these parts are in satisfac-
tory condition, disassemble the master cylinder and
check for an elongated or swollen primary cylinder or
piston seals. If swollen seals are found, substandard
or contaminated brake fluid should be suspected. If
contaminated brake fluid is found, all the components
should be disassembled and cleaned, and all the rub-
ber components should be replaced. All of the pipes
must also be flushed.

Improper brake fluid, or mineral oil or water in the fluid,
may cause the brake fluid to boil or cause deterioration
of the rubber components. If the primary piston cups in
the master cylinder are swollen, then the rubber parts
have deteriorated. This deterioration may also be evi-
denced by swollen wheel cylinder piston seals on the
drum brake wheels.

If rubber deterioration is evident, disassemble all the hy-
draulic parts and wash the parts with alcohol. Dry these
parts with compressed air before reassembly to keep al-
cohol out of the system. Replace all the rubber parts in
the system, including the hoses. Also, when working on
the brake mechanisms, check for fluid on the linings. If
excessive fluid is found, replace the linings.

If the master cylinder piston seals are in satisfactory
condition, check for leaks or excessive heat conditions.
If these conditions are not found, drain the fluid, flush the
master cylinder with brake fluid, refill the master cylin-
der, and bleed the system. Refer to “Manual Bleeding
the Brakes” in this section.

BRAKE HOSE INSPECTION

The hydraulic brake hoses should be inspected at least
twice a year. The brake hose assembly should be
checked for road hazard damage, cracks, chafing of the
outer cover, and for leaks or blisters. Inspect the hoses
for proper routing and mounting. A brake hose that rubs
on a suspension component will wear and eventually
fail. A light and a mirror may be needed for an adequate
inspection. If any of the above conditions are observed
on the brake hose, adjust or replace the hose as neces-
sary.

HYDRAULIC BRAKES 4A – 5

WARNING LAMP OPERATION

This brake system uses a BRAKE warning lamp located
in the instrument panel cluster. When the ignition switch
is in the

III

position, the BRAKE warning lamp should

glow and then go OFF when the ignition switch returns
to the

position.

The following conditions will activate the BRAKE lamp:

Parking brake applied. The light should be on when-
ever the parking brake is applied and the ignition
switch is

Low fluid level. A low fluid level in the master cylinder
will turn the BRAKE lamp ON.

BRAKE SYSTEM FAULT

ÁÁÁÁÁÁÁÁÁÁ

Condition

ÁÁÁÁÁÁÁÁÁÁÁÁÁ

Probable cause

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Correction

Brake Warning Lamp ON

Brake fluid leaks.

Repair the leaks or add th fluid.

Parking brake switch shorted to
ground.

Repair the short ground.

Faulty the fluid level sensor.

Replace the sensor.

Stoplamp ON

Faulty the stoplamp switch.

Replace the stoplamp switch.

Push rod length is short.

Adjust the push rod length of the
power booster.

Stoplamp switch circuit shorted to
battery.

Repair or Replace the wiring harness.

Poor Braking

Brake fluid lacks or leaks.

Repair the leaks or add the fluid.

Brake fluid contamination.

Replace the fluid.

Air in the brake system.

Bleed the brake system.

Damaged brake lines.

Replace the brake lines.

Damaged vacuum hose or faulty
check valve.

Replace the vacuum hose or check
value.

Dragging Brake

No free play at the brake pedal.

Adjust the free play.

Weakened the brake pedal return
spring.

Replace the return spring.

Faulty master cylinder.

Replace the master cylinder.

Air in the brake system.

Bleed the brake system.

Pedal Over Stroke

Brake fluid lacks or leaks.

Repair the leaks or add the fluid.

Poor adjustment of the brake pedal
free play.

Adjust the push rod length of the
power booster.

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