2002 ISUZU AXIOM brake light

5C±7 POWER±ASSISTED BRAKE SYSTEM
General Diagnosis
ConditionPossible causeCorrection
Brake PullTire inflation pressure is unequal.Adjust
Front wheel alignment is incorrect.Adjust
Unmatched tires on same axle.Tires with approx. the same amount
of tread should be used on the same
axle.
Restricted brake pipes or hoses.Check for soft hoses and damaged
lines. Replace with new hoses and
new doubleªwalled steel brake
piping.
Water or oil on the brake pads.Clean or replace.
Brake pads hardened.Replace
Brake pads worn excessively.Replace
Brake rotor worn or scored.Grind or replace.
Disc brake caliper malfunctioning.Clean or replace.
Front hub bearing preload incorrect.Adjust or replace.
Loose suspension parts.Check all suspension mountings.
Loose calipers.Check and tighten the bolts to
specifications.
Brake Roughness or Chatter
(Pulsates)Excessive lateral runout.Check per instructions. If not within
specifications, replace or machine
the rotor.
Parallelism not within specifications.Check per instructions. If not within
specifications, replace or machine
the rotor.
Wheel bearings not adjusted.Adjust wheel bearings to correct
specifications
Pad reversed (steel against iron).Replace the brake pad and machine
rotor to within specifications.
Excessive Pedal EffortMalfunctioning vacuum booster.Check the vacuum booster operation
and repair, if necessary.
Partial system failure.Check the front and rear brake
system for failure and repair. Also,
check the brake warning light. If a
failed system is found, the light
should indicate failure.
Excessively worn pad.Check and replace pads in sets.
Piston in caliper stuck or sluggish.Remove caliper and rebuild.
Fading brakes due to incorrect pad.Remove and replace with original
equipment pad or equivalent.
Vacuum leak to vacuum booster.Check for ruptured or loose hose.
Check the direction of check valve
within vacuum hose.Correct vacuum hose direction.
Grease on the brake pads.Replace or clean.

5C±8
POWER±ASSISTED BRAKE SYSTEM
Condition CorrectionPossible cause
Excessive Brake Pedal TravelAir in hydraulic circuit.Bleed the hydraulic circuit.
Level of brake fluid in the reservoir
too low.Replenish brake fluid reservoir to
specified level and bleed hydraulic
circuit as necessary.
Master cylinder push rod clearance
excessive.Adjust
Leakage in hydraulic system.Correct or replace defective parts.
Brake DragMaster cylinder pistons not returning
correctly.Adjust the stop light switch and
vacuum booster push rod. If
necessary, rebuild.
Restricted brake pipes or hoses.Check for soft hoses or damaged
pipes, and replace with new hoses
and new double±walled steel brake
piping.
Parking brake maladjusted.Adjust
Parking brake lining clearance
insufficient.Adjust
Brake pedal free play insufficient.Adjust the brake pedal height or
power cylinder operating rod.
Piston in the master cylinder sticking.Replace
Piston in the disc brake caliper
sticking.Replace piston seals.
Brake pads sticking in caliper.Clean
Return spring weakened.Replace
Parking brake binding.Overhaul the parking brakes and
correct.
Front hub bearing preload incorrect.Adjust or replace.
Parking brake shoes not returning.Correct or replace the brake back
plate and brake shoe as necessary.
Obstructions in hydraulic circuit.Clean
Rotor warped excessively.Grind or replace.
Rear brake drum distorted.Grind or replace.
Parking cable sticking.Grind or replace.
Grabbing or Uneven Braking Action
(All conditions listed under ªPullsº)Malfunctioning vacuum booster.Check operation and correct as
necessary.
Binding brake pedal mechanism.Check and lubricate, if necessary.
Corroded caliper assembly.Clean and lubricate.
Brake NoisyBrake pads are worn.Replace
Brake pads are hardened.Replace
Brake pads are in poor contact with
rotor.Correct
Brake disc(s) warped, worn or
damaged.Grind or replace.
Disc brake anti±squeak shims
fatigued.Replace
Front hub bearings are loose or
preload is incorrect.Adjust or replace.
Brake disc is rusted.Grind or replace.

5C±11 POWER±ASSISTED BRAKE SYSTEM
330RW012
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:

Right rear caliper or wheel cylinder

Left rear caliper or wheel cylinder

Right front caliper

Left 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 or
wheel cylinder.
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. Loosen the bleeder screw until fluid flows through the
tube.
23. Retighten the bleeder screw.
24. Release the brake pedal slowly.
25. Repeat steps 21 through 24 until the air is completely
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 wheel
is bled.
Be sure to monitor reservoir fluid level.
27. Depress the brake pedal to check if you feel
ªsponginessº after the air has been removed from all
wheel cylinders and calipers.
If the pedal feels ªspongyº, the entire bleeding
procedure must be repeated.28. After the bleeding operation is completed on the each
individual wheel, check the level of the brake fluid in
the reservoir and replenish up to the ªMAXº level as
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 hydraulic 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 the Brake
Hydraulic System
in this section.
Brake Hose Inspection
The brake hose 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.

5C±15 POWER±ASSISTED BRAKE SYSTEM
P & B (Proportioning and Bypass) Valve
P & B (Proportioning and Bypass)
Valve Sectional View
350RW014
Legend
(1) Master Cylinder (Secondary)
(2) Master Cylinder (Primary)
(3) Rear Brake
(4) Front Brake
The P&B valve contains two sections, each serving a
different function.
The proportioning section of the P&B valve proportions
outlet pressure to the rear brakes after a predetermined
rear input pressure has been reached. This is done to
prevent rear wheel lock up on the vehicles with light rear
wheel loads. The valve has a by±pass feature which
assures full system pressure to the rear brakes in the
event of front brake system malfunction. Also full front
pressure is retained in the event of rear brake
malfunction.
The P&B valve is not repairable and must be replaced as
complete assembly.
Removal
1. The P&B valve is not repairable and must be replaced
as a complete assembly. Care must be taken to
prevent brake fluid from contacting any painted
surface.
2. Remove hydraulic pipes (1) and plug the pipes (1) to
prevent the loss of fluid or the entrance of dirt.
3. Remove bolt (3).
4. Remove P&B valve (2).
350RW026
Installation
1. Install P&B valve (2).
2. Install bolt (3) and tighten the bolt to the specified
torque.
Torque: 22 N´m (16 lb ft)
3. Install hydraulic pipes (1) and tighten the bolt to the
specified torque.
Torque: 15 N´m (11 lb ft)
4. After installing the brake pipes, bleed the brakes as
refer to
Bleeding Brake Hydraulic System in this
section.

5C±17 POWER±ASSISTED BRAKE SYSTEM
Brake Pedal
Checking 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
310RY00004
1. Measure the brake pedal height after making sure the
pedal is fully returned by the pedal return spring.
Pedal height must be measured after starting the
engine and receiving it several times.
Pedal Free Play: 6-10 mm (0.23-0.39 in)
Pedal Free Play: 173-185 mm (6.81-7.28 in)
NOTE: Pedal free play 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 stoplight switch connector.
b. Loosen the stoplight switch lock nut.
c. Rotate the stoplight switch so that it moves away
from the brake pedal.
d. Loosen the lock nut (1) 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.
Torque: 20 N´m (15 lb ft)
g. Adjust the stoplight switch (2) to the specified
clearance (between the switch housing and the
brake pedal) by rotating the switch housing.
Clearance: 0.5±1.0 mm (0.02±0.04 in)
310RY00005
NOTE: While adjusting the stoplight switch, make sure
that the threaded part of the stoplight switch does not
push the brake pedal.
h. Tighten the stoplight switch lock nut.
i. Connect the stoplight switch connector.
Checking Pedal Travel
310RY00004
1. Pedal height must be measured after starting the
engine and revving it several times to apply vacuum
to the vacuum booster fully.
NOTE: Pedal height must be 95 mm (3.7 in) 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 may still be present in the hydraulic system
Perform the bleeding procedure.

5C±18
POWER±ASSISTED BRAKE SYSTEM
Brake Pedal and Associated Parts
310RY00006
Legend
(1) Brake Pedal Bracket Assembly
(2) Fulcrum Pin and Nut
(3) Connector
(4) Snap Pin
(5) Return Spring(6) Peadl Assembly
(7) Push Rod Pin
(8) Lower Cover
(9) Bolts and Nut
(10) Driver Knee Bolster
Removal
1. Disconnect the battery ª±º terminal cable, and wait at
least 5 minutes.
2. Disconnect the yellow 3 way SRS connector located
under the steering column.
3. Remove the engine hood opening lever.
4. Remove lower cover (8).
5. Remove driver knee bolster (10).
6. Disconnect the stop light switch connector (3).
Disconnect the anti-theft control module connector.
Refer to
Body and Accessories section in this
Manual.
7. Remove snap pin (4) and push rod pin (7).
8. Remove the steering column shaft fixing bolt and nut
(9) on the steering wheel side, and lower the steering
column shaft.
9. Remove the brake pedal bracket assembly (1).
10. Remove return spring (5).
11. Remove fulcrum pin and nut (2).12. Remove pedal assembly (6).
Installation
1. Apply grease to the entire circumference of the
fulcrum pin.
2. Install pedal assembly (6) and fulcrum pin and nut (2).
Tighten the nut (2) to the specified torque.
Torque: 35 N´m (26 lb ft)
3. Install the brake pedal bracket assembly (1).
Tighten the bolts and nuts soecified torque.
Torque: 15 N´m (11 lb ft)
4. Install return spring (5).
5. Adjust pedal free travel.
Refer to
Brake Pedal Adjustment in this section.
6. Tighten the steering column fixing bolt (9) (dash
panel) to the specified torque.
Torque: 20 N´m (14 lb ft)

5C±19 POWER±ASSISTED BRAKE SYSTEM
7. Tighten the steering column fixing nut (9) (Cross
Beam) to the specified torque.
Torque: 17 N´m (12 lb ft)
8. Apply grease to the entire circumference of the Push
rod pin (7).
9. Install push rod pin (7).
10. Install snap pin (4).
11. Connect the anti-theft control module connector.
Refer to
Body and Accessories section in this
manual.12. Connect the stop light switch connector (3).
13. Install driver knee bolster (10) and lower cover (8).
14. Install the engine hood opening lever.
15. Connect the yellow 3 way SRS connector located
under the steering column.
16. Connect the battery ª±º terminal cable.
Stoplight Switch
Parts Location
310RW008
Legend
(1) Connector
(2) Switch
(3) Lock Nut
Removal
1. Disconnect connector (1)
2. Remove lock nut (3).
3. Remove switch (2).
Installation
1. Adjust the stop light switch to the specified clearance
(between switch housing and brake pedal) by rotating
the switch housing.
Clearance : 0-0.2 mm (0-0.08 in)
NOTE: Do not attempt to force the push rod into position
during the stop light switch installation and adjustment
procedure.
310RY00005
2. Connect connector (1).
3. Install lock nut (3).

5C±55 POWER±ASSISTED BRAKE SYSTEM
NOTE: Do not over stretch the return spring.
305RS003
9. Remove upper (inner) return spring (9).
10. Remove hold-down spring and cup (3) and hold-down
pin (16).
11. Remove Trailing shoe assembly (7) with parking
brake lever (16).
12. Remove parking brake cable from parking brake lever
(11).
13. Remove retainer (14), wave washer (13), and parking
brake lever (11).
Brake Lining Inspection
Check the shoe assemblies for wear by removing brake
drum.
Replace the shoe assemblies, if lining thickness is less
than 1.0 mm (0.039 in).
The shoe assemblies have a wear indicator that makes a
noise when the linings wear to a degree where
replacement is required.
Minimum limit: 1.0 mm (0.039 in)
305RS001
Installation
1. Apply grease lightly to back place A.
305RW002
Legend
(1) Place A (3 portions for each side)
2. Install parking brake lever (11), wave washer (13),
and retainer (14).
3. Install trailing shoe assembly (7) with parking brake
lever (16).
4. Install the parking brake cable to parking brake lever
(11).
5. Install hold-down pin (16) and hold-down spring and
cup (3).
6. Install upper (inner) return spring (9).
7. Install leading shoe assembly (8) with upper (inner)
return spring (9).
NOTE: Do not over stretch the return spring.
305RS003
8. Install adjuster assembly (12).
9. Install hold-down pin (15) and hold-down spring and
cups (4).