Opel Frontera UBS. Manual - part 216

POWER ASSISTED BRAKE SYSTEM  5C – 9

SERVICING

FILLING MASTER CYLINDER RESERVOIR

CAUTION:

1) Use only specified brake fluid. Do not use any

fluid which contains a petroleum base. Do not
use a container which has been used for
petroleum based fluids or a container which is
wet with water. Petroleum based fluids will
cause swelling and distortion of rubber parts in
the hydraulic brake system. Water mixed with
brake fluid lowers the fluid boiling point. Keep all
fluid containers capped to prevent
contamination.

2) Always fill the master cylinder reservoid when

the engine is cold.

3) Never allow the brake fluid to come in contact

with the painted surfaced.

The master cylinder reservoir must be kept properly
filled to ensure adequate reserve and to prevent air
and moisture from entering the hydraulic system.
However, because of expansion due to heat absorbed
from the brakes and the engine, the reservoir must not
be overfilled. The brake fluid reservoir is on the
master cylinder, which is located under the hood on
the driver side of the cowl. Thoroughly clean reservoir
cap before removal to avoid getting dirt into reservoir.
Remove cap and diaphragm. Add fluid as required to
bring level to the “MAX” mark on the reservoir tank.
Use “DOT 3“ Hydraulic Brake Fluid. If the fluid cap
diaphragm is stretched, return it to the original
position before installing.

DETERIORATION OF BRAKE FLUID

Using any other brake fluid than speficied or brake
fluid with mineral oil or water mixed in will drop the
boiling point of brake fluid. It may, in turn, reuslt in
vapor lock or deteriorated rubber parts of the
hydraulic system. Be sure to change brake fluid at
specified intervals.
If rubber parts are deteriorated, remover all the
system parts and clean them with alcohol. Prior to
reassembly, dry the cleaned parts with air to remove
the alcohol. Replace all hoses and rubber parts of the
system.

LEAKAGE OF BRAKE FLUID

With engine idling, set shift lever in the neutral
position and continue to depress brake pedal at a
constant pedal application force.
Should the pedal stroke become deeper gradually,
leak from the hydraulic pressure system is possible.
Make sure by visual check that there is no leak.

5C – 10 POWER ASSISTED BRAKE SYSTEM

BLEEDING BRAKE HYDRAULIC SYSTEM

A bleeding operation is necessary to remove air from
the hydraulic brake system whenever air is introduced
into the hydraulic system. It may be necessary to
bleed the hydraulic system at all four brakes if air has
been introduced through a low fluid level or by
disconnecting brake pipes at the master cylinder. If a
brake pipe is disconneted at one wheel, only that
wheel cylinder/caliper needs to be bled. If pipes are
disconnected at any fitting located between master
cylinder and brakes, then the brake system served by
the disconnected pipe must be bled.

1. For 4-wheel Antilock Brake System (ABS)

equipped vehicle, be sure to remove the ABS main
fuse 40A located at the relay and fuse box  before
bleeding air. If you attempt to bleed air without
removing the main fuse, air cannot be let out
thoroughly, and this may cause damage to the
hydraulic unit. After bleeding air, be sure to
replace the ABS main fuse back to its original
position.

2. Set the parking brake completely, then start the

engine.

NOTE:
The vacuum booster will be damaged if the bleeding
operation is performed with the engine off.

3. Remove the master cylinder reservoir cap.
4. Fill the master cylinder reservoir with brake fluid.

Keep the reservoir at least half full during the air
bleeding operation.

5. Always use new brake fluid for replenishment.
6. In replenishing brake fluid, take care that air

bubbles do not enter the brake fluid.

•

When the master cylinder is replaced or
overhauled, first bleed the air from the master
cylinder, then from each wheel cylinder and
caliper following the procedures described
below.

Bleeding the Master Cylinder

7. Disconnect the rear wheel brake pipe 1 from the

master cylinder. Check the fluid level and
replenish as necessary. If replenished, leave the
system for at least one minute.

8. Depress the brake pedal slowly once and hold it

depressed.

9. Completely seal the delivery port of the master

cylinder where the pipe was disconnected with
your finger, then release the brake pedal slowly.

10. Release your finger from the delivery port when

the brake pedal returns completely.

11. Repeat steps 7 through 9 until the brake fluid

comes out of the delivery port during step 7.

NOTE:
Do not allow the fluid level in the reservoir to go
below the half-way mark.

2

1

POWER ASSISTED BRAKE SYSTEM  5C – 11

12. Reconnect the brake pipe 1 to the master cylinder

and tighten the pipe.

13. Depress the brake pedal slowly once and hold it

depressed.

14. Loosen the rear wheel brake pipe 1 at the master

cylinder.

15. Retighten the brake pipe, then release the brake

pedal slowly.

16. Repeat steps 13 through 15 until no air comes out

from the port when the brake pipe is loosened.

NOTE:
Be very careful not to allow the brake fluid to come in
contact with painted surfaces.

17. Bleed the air from the front wheel brake pipe

connection 2 by repeating steps 7 through 16.

Bleeding the Caliper

18. Bleed the air from each wheel in the order listed

below.
LHD models:
1) Right rear caliper
2) Left rear caliper
3) Load sensing proportioning valve (only for

Europe and South Africa)

4) Right front caliper
5) Left front caliper
RHD models:
1) Left rear caliper
2) Right rear caliper
3) Load sensing proportioning valve (only for

Europe and South Africa)

4) Left front caliper
5) Right front caliper

Conduct air bleeding from the wheels in the above
order. If no brake fluid comes out, it suggests that air
is mixed in the master cylinder. In this case, bleed air
from the master cylinder in accordance with Steps 7
through 17, and then bleed air from the caliper.

19. Place the proper size box end wrench over the

bleeder screw.

20. Cover the bleeder screw with a transparent tube,

and submerge the free end of the transparent tube
in a transparent container containing brake fluid.

21. Pump the brake pedal slowly three (3) times

(once/sec), then hold it depressed.

22. Loose the bleeder screw until fluid flows through

the tube.

23. Retighten the bleeder screw.
24. Release the brake pedal slowly.
25. Repeat step 21 through 24 until the air is

compeletely removed. It may be necessary to
repeat the bleeding procedure 10 or more times
for front wheels and 15 or more times for rear
wheels.

26. Go to the next wheel in the sequence after each

wheels is bled. Be sure to monitor reservoir fluid
level.

5C – 12 POWER ASSISTED BRAKE SYSTEM

27. Depress the brake pedal to check if you feel

“sponginess” after the air has been removed from
all wheel cylinders and calipers. If the pedal feels
“spongy”, the entire bleeding procedure must be
repeated.

28. After the bleeding operation is completed on each

individual wheel, check the level of brake fluid in
the reservoir and replenish up to the “MAX” level if
necessary.

29. Attach the reservoir cap.

•

If the diaphragm inside the cap is deformed,
reform it and install.

30. Stop the engine.

FLUSHING BRAKE HYDRAULIC SYSTEM

It is recommended that the entire hydraulic system be
thoroughly flushed with clean brake fluid whenever
new parts are installed in the hydraluic system.
Approximately one quart of fluid is required to flush
the hydraulic system.
The system must be flushed if there is any doubt as to
the grade of fluid in the system or if fluid has been
used which contains the slightest trace of mineral oil.
All rubber parts that have been subjected to a
contaminated fluid must be replaced.

BRAKE PIPES AND HOSES

The hydraulic brake system components are
interconnected by special steel piping and flexible
hoses. Flexible hoses are used between the frame and
the front calipers, the frame and rear axle case and the
rear axle and the rear calipers.
When the hydraulic pipes have been disconnected for
any reason, the brake system must be bled after
reconnecting the pipe; refer to “Bleeding Brake
Hydraulic System” in this section.

BRAKE HOSE INSPECTION

The brake hoses should be inspected at least twice a
year. The brake hose assembly should be checked for
road hazard, cracks and chafing of the outer cover,
and for leaks and blisters. Inspect for proper routing
and mounting of the hose. A brake hose that rubs on
suspension components will wear and eventually fail.
A light and 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 necessary.

CAUTION:
Never allow brake components such as calipers to
hang from the brake hoses, as damage to the hoses
may occur.