Opel Frontera UBS. Service manual — part 1102

POWER ASSISTED BRAKE SYSTEM 5C – 13

CHECKING BRAKE PEDAL HEIGHT

The push rod serves as the brake pedal stopper when
the pedal is fully released. Brake pedal height
adjustment should be performed as follows:

Adjust Brake Pedal
1. Measure the brake pedal height after making sure

the pedal is fully returned by the pedal return
spring.
Pedal height (L2) must be measured after starting
the engine and revving it several times.

Pedal Free Play (L1)

mm (in)

6 – 10 (0.23 – 0.39)

Pedal Height (L2)

mm (in)

LHD

RHD

208 – 218

211 – 221

(8.19 – 8.58)

(8.31 – 8.70)

NOTE:
Pedal free play (L1) must be measured after turning
off the engine and stepping on the brake pedal firmly
five times or more.

2. If the measured value is not within the above

range, adjust the brake pedal as follows:
a) Disconnect the stop light switch connector.
b) Loosen the stop light switch lock nut.
c) Rotate the stop light switch so that it moves

away from the brake pedal.

d) Loosen the lock nut on the push rod.
e) Adjust the brake pedal to the specified height

by rotating the push rod in the appropriate
direction.

f)

Tighten the lock nut to the specified torque.

Lock Nut Torque

N·m (kg·m/lb·ft)

20 (2.0 / 15)

g) Adjust the stop light switch to the specified

clearance (between switch housing and brake
pedal) by rotating the switch housing.

Clearance

mm (in)

0 – 0.2 (0 – 0.008)

NOTE:
While adjusting the installation of the stoplight
switch, make sure that the threaded part of the
stoplight switch does not push the brake pedal.

h) Tighten the stop light switch lock nut.
i)

Connect the stop light switch connector.

Switch

Floor panel

(L3)

(A)

(L2)

(L1)

Lock nut

(A)

5C – 14 POWER ASSISTED BRAKE SYSTEM

CHECKING BRAKE PEDAL TRAVEL

1. Pedal height (L3) must be measured after starting

the engine and removing it several times to apply
vacuum to the vacuum booster fully.

NOTE:
Pedal height (L3) must be 100 mm (3.9 in)/85 mm (3.5
in) (LHD/RHD) or more when about 50 kg (110.25 lb)
of stepping force is applied.

2. If the measured value is lower than the above

range, air existing in the hydrauic system is
suspected and perform bleeding procedure.

FRONT AND REAR DISC BRAKE PADS
INSPECTION

Check the outer pad by looking at each caliper from
above. Check the thickness on the inner pad by
looking down through the inspection hole in the top of
the caliper. Whenever the pad is worn to about the
thickness of the pad base, the pad should be removed
for further measurements. The pad should be
replaced anytime the pad thickness (t) is worn to
within 1.0 mm (0.039 in) of the pad itself.
The disc pads have a wear indicator that makes a
noise when the pad wears to where replacement is
required.

Minimum Limit

mm (in)

1.0 (0.039)

SERVICING THE FRONT BRAKE ROTOR

In the manufacturing of the front brake rotor, all the
tolerances regarding surface finish, parallelism and
lateral runout are held very closely. The maintenance
of these tolerances provide the surface necessary to
assure smooth brake operation.

LATERAL RUNOUT

Lateral runout is the movement of the rotor from side
to side as it rotates on the spindle. This could also be
referred to as “rotor wobble”.
This movement causes the piston to be knocked back
into its bore. This results in additional pedal travel and
a vibration during braking.

t

POWER ASSISTED BRAKE SYSTEM 5C – 15

CHECKING LATERAL RUNOUT

1. Adjust the wheel bearing correctly.

•

Refer to Front Hub and Disc in Driveline / Axle
Section.

2. Attach a dial indicator to some portion of the

suspension so that the stem contacts the rotor
face about 29 mm (1.14 in) from the rotor edge.

3. Move the rotor one complete rotation.

•

The lateral runout should not exceed 0.13 mm
(0.005 in).

Maximum Runout

mm (in)

0.13 (0.005)

PARALLELISM

Parallelism is the measurement of the thickness of the
rotor at four or more points around the circumference
of the rotor. All measurement must be made at 29 mm
(1.14 in) from the edge of the rotor.
The rotor thickness must not vary more than 0.010
mm (0.004 in) from point to point.

Maximum Parallelism

mm (in)

0.010 (0.0004)

REPLACING FRONT BRAKE ROTORS

When installing new brake rotors, do not refinish the
surfaces. These parts are at the correct level of surface
finish.

REFINISHING FRONT BRAKE ROTORS

Accurate control of the rotor tolerances is necessary
for proper performance of the disc brakes. Machining
of the rotor should be done only with precision
equipment. All brake rotors have a minimum
thickness dimension cast into them. This dimension is
the minimum wear dimension and not a refinish
dimension. The minimum wear dimension is 24.60
mm (0.969 in). The minimum refinish dimension is
24.97 mm (0.983 in).
When refinishing rotors, always use sharp cutting
tools or bits. Dull or worn tools leave a poor surface
finish which will affect initial braking performance.
Vibration dampening attachments should always be
used when refinishing braking surfaces. These
attachments eliminate tool chatter and will result in
better surface finish.
After refinishing, replace any rotor that does not meet
the minimum thickness of 24.97 mm (0.983 in). Do not
use a brake rotor that will not meet the specification.

Minimum Wear Dimension

mm (in)

24.60 (0.969)

Refinish Dimension

mm (in)

24.97 (0.983)

t

5C – 16 POWER ASSISTED BRAKE SYSTEM

PARALLELSIM

Parallelism is the measurement of the thickness of the
rotor at four or more points around the circumference
of the rotor. All measurements must be made at 22 mm
(0.87 in) from the edge of the rotor.
The rotor thickness must not vary more than 0.010
mm (0.0004 in) from point to point.

Maximum Parallelism Variation

mm (in)

0.010 (0.0004)

REPLACING REAR BRAKE ROTORS

When installing new brake rotors, do not refinish the
surfaces. These parts are at the correct level of surface
finish.

REFINISHING REAR BRAKE ROTORS

Accurate control of the rotor tolerances is necessary
for proper performance of the disc brakes. Machining
of the rotor should be done only with precision
equipment. All brake rotors have a minimum
thickness dimension cast into them. This dimension is
the minimum wear dimension and not a refinish
dimension. The minimum wear dimension is 16.60
mm (0.654 in). The refinish dimension is 16.97 mm
(0.668 in).
When refinishing rotors, always use sharp cutting
tools or bits. Dull or worn tools leave a poor surface
finish which will affect initial braking performance.

SERVICING THE REAR BRAKE ROTOR

In the manufacturing of the rear brake rotor, all the
tolerances regarding surface finish, parallelism and
lateral runout are held very closely. The maintenance
of these tolerances provide the surface necessary to
assure smooth brake operation.

LATERAL RUNOUT

Lateral runout is the movement of the rotor from side
to side as it rotates on the spindle. This could also be
referred to as “rotor wobble”.
This movement causes the piston to be knocked back
into its bore. This results in additional pedal travel and
a vibration during braking.

CHECKING LATERAL RUNOUT

1. Attach a dial indicator to some portion of the

suspension so that the stem contacts the rotor
face about 22 mm (0.87 in) from the rotor edge.

2. Move the rotor one complete rotation.

•

The lateral runout should not exceed 0.13 mm
(0.005 in).

Maximum Runout

mm (in)

0.13 (0.005)

t