Isuzu Trooper (1998-2002 year). Manual - part 215

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.

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