parking brake ISUZU TROOPER 1995 Owner's Manual

SA-2 HYDRAULIC BRAKES
BRAKE SYSTEM DIAGNOSIS
ROAD TESTING THE BRAKES
Brake Test
Brakes should be tested on a dry, clean, reasonably
smooth and
level roadway. A true test of brake
performance cannot be made
if the roadway is
wet, greasy
or covered with loose dirt so that 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 of the vehicle toward
wheels on one side or if the roadway is so rough
that wheels tend to bounce. Test the brakes at dif­
ferent vehicle speeds with both light and heavy
pedal pressure; however, avoid locking the wheels
and sliding the tires. Locked wheels and sliding
tires do not indicate brake efficiency, since heavily
braked but turning wheels will stop the vehicle in
less distance than locked wheels. More tire-to-road
friction is present
with a heavily braked turning tire
then
with a sliding tire.
The standard brake system is designed and
balanced
to avoid locking the wheels except at very high
deceleration
levels.
It
is designed this way because the shortest stopping
distance and best
control is achieved without brake
lock-up.
Because of high deceleration capability, a firmer pedal
may be felt at higher deceleration levels.
External Conditions That Affect Brake
Performance
1.
2.
3.
Tires: Tires having unequal contact and grip on
the road
will cause unequal braking. Tires must
be equally inflated, identical in size, and the tread
pattern
of right and left tires must be approxi­
mately equal.
Vehicle loading:
A heavily loaded vehicle requires
more braking effort.
Wheel Alignment: Misalignment of the wheels,
particularly
in regard to excessive camber and
caster,
will cause the brakes to pull to one side.
BRAKE FLUID LEAKS
With engine running at idle and the transmission in
"Neutral", depress the brake pedal and hold a constant
foot pressure on the pedal. If pedal gradually falls
away with the constant pressure, the hydraulic system
may be leaking.
Check the master cylinder fluid level. While a slight
drop in reservoir level will result from normal lining
wear, an abnormally low level in reservoir indicates a
leak in the system. The hydraulic system may be
leaking internally as well as externally. Refer to
"Master Cylinder Inspection". Also, the system may
appear
to pass this test but still have slight leakage. If
fluid level
is normal, check the vacuum booster
push rod
length. If an incorrect length push rod is
found, adjust
or replace the push rod. Check the
brake
pedal travel and the parking brake adjust­
ment.
When checking the
fluid level, the master cylinder fluid
level
may be low from the "MAX" mark if the front and
rear
linings are worn. This is not abnormal.
WARNING LIGHT OPERATION
When the ignition switch is in the START position,
the
"BRAKE" warning light should glow and go off
when the ignition switch returns to the ON position.
The
following conditions will activate the "BRAKE"
light:
1. Parking brake applied. The light should be on
whenever the parking brake is applied and the
ignition switch is on.
2. Low fluid level. A low fluid level in the master
cylinder will turn the "BRAKE" light on (Except
Rear
Wheel Antilock Brake System (RWAL)
model).
3. During engine cranking the "BRAKE" light
should
remain on. This notifies the driver that
the warning circuit is operating properly.
4. In the event of a front or rear system malfunc­
tion (RWAL model only).
5. In the event of RWAL malfunction (RWAL
model only. Refer to Section 5A3).
ANTILOCK BRAKE SYSTEM (RWAL or
ABS}
Refer to Section 5A3 or 5A4 for inspection and di­
agnosis procedure of the hydraulic unit.
..

SA-4 HYDRAULIC BRAKES
Condition Possible Cause Correction
Brake Drag
1. Master cylinder pistons not returning 1. Adjust stop light switch and vacuum
correctly. booster operating rod. If necessary,
rebuild.
2. Restricted brake pipes or hoses. 2. Check for soft hoses or damaged pipes,
and
replace with new hoses and new
double-walled steel brake piping.
3. Parking brake maladjusted. 3. Adjust.
4. Parking brake lining clearance 4. Adjust
insufficient.
5. Brake pedal free play insufficient. 5. Adjust brake pedal height or power
cylinder operating rod.
6. Piston in master cylinder sticking. 6. Replace.
7. Piston in disc brake caliper sticking. 7. Replace piston seals.
8. Brake pads sticking in caliper. 8. Clean.
9. Return spring weakened. 9. Replace.
10. Praking brake binding. 10. Overhaul parking brakes and correct.
11. Front hub bearing preload incorrect. 11.
Adjust or replace.
12. Parking brake shoes not returning. 12.
Correct or replace brake back plate and
brake shoe
as necessary.
13. Obstructions in hydraulic circuit. 13. Clean.
14. Rotor warped excessively. 14.
Grind or replace.
15. Rear brake drum distorted. 15.
Grind or replace.
16. Check valve; vacuum hose faulty. 16. Replace.
17. Parking cable sticking. 17. Clean or replace.
Grabbing
or 1. Malfunctioning vacuum booster. 1. Check operation and correct as
Uneven Braking necessary.
Action
(All 2. Binding brake pedal mechanism. 2. Check and lubricate, if necessary.
conditions
3. Corroded caliper assembly. 3. Clean and lubricate.
listed
under
"Pulls")
Brake Noisy 1 . Brake pads worn. 1. Replace.
2. Brake pads hardened. 2. Replace.
3. Brake pads in poor contact with rotor. 3. Correct.
4. Brake disc(s) warped, worn or 4. Grind or replace.
damaged.
5. Disc brake anti-squeak shims fatigued. 5. Replace.
6. Front hub bearings loose or preload is 6. Adjust or replace.
incorrect.
7. Brake disc rusted. 7. Grind or replace.
Poor Brake 1. Master cylinder faulty. 1. Correct or replace.
Action 2. Vacuum booster faulty. 2. Correct or replace.
3. Level of brake fluid in reservoir too 3. Replenish and bleed.
low.
4. Air in hydraulic circuit. 4. Bleed.
5. Disc brake caliper faulty. 5. Clean or replace.
6. Water or oil on brake pads. 6. Clean or replace.
7. Brake pads in poor contact with rotor. 7. Correct.
8. Brake pads worn. 8. Replace.
9. Brake disc rusted. 9. Grind or replace.
10. Check valve in vacuum hose faulty. 10. Correct or replace.
•

HYDRAULIC BRAKES 5A-5
ON-VEHICLE SERVICE
FILLING MASTER CYLINDER
RESERVOIR
'\fl CAUTION:
'VI • 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 contami­
nation.
• Always fill the master cylinder reservoir when
the engine is
cold.
•
Never allow the brake fluid to come in contact
with the painted surfaces.
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
left
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 specified or brake fluid
with mineral oil or water mixed in will drop the boiling
point of brake fluid. It may, in turn, result 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, remove 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
pressure.
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.
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 dis­
connecting brake pipes at the master cylinder. If a
brake pipe is disconnected 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 (Fig. 5A-1}
7. Disconnect the rear wheel brake pipe master
cylinder (Fig. 5A-1 ). 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.

HYDRAULIC BRAKES 5A-21
MAIN DATA AND SPECIFICATIONS
GENERAL SPECIFICATIONS
Brake pedal
Pedal
free play
Pedal
height
Parking brake
Type Brake
handle(stem) travel
Master cylinder
Type
Piston bore diameter
TORQUE SPECIFICATIONS
mm (in)
mm (in)
mm (in)
13 (1131b·in)
Fig. 5A-23 6
to 10 (0.23 to 0.39)
208 to 218
(8.19 to 8.58)
Duo-servo
6 to 7 notches
When
pulled with a force of 30 kg (66 lb)
Dual-circuit
25.4 (1.000)
4-Wheel Antilock Brake System
N·m {lb·ft}
-Brake fluid pipe line -Flexible hose
Rear Wheel Antilock Brake System
-Brake fluid pipe line -Flexible hose

DISC BRAKES 5A2-1
SECTION 5A2
DISC BRAKES
w CAUTION:
All brake attaching fasteners are an important attaching part in that they could affect performance of vital
parts and systems, and/or could result in major repair expense. They must be replaced with one of the same
part
number or with an equivalent part if replacement becomes necessary. Do not use replacement parts of
lesser quality or substitute design. Torque values must be used as specified during reassembly to assure
proper retention of these parts.
CONTENTS
General Description . . . . . . . . . . . . . . . . . . . . 5A2-1
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5A2-1
Diagnosis
..................... See Section SA
On-Vehicle Service . . . . . . . . . . . . . . . . . . . . 5A2-2
Front Disc Brakes . . . . . . . . . . . . . . . . . . . . 5A2-2
Brake Pads
Inspection . .

. . . . . . . . . . . . 5A2-2
Brake Pads Replacement . . . . . . . . . . . 5A2-3
Servicing
the Rotor . . . . . . . . . . . . . . . . 5A2-4
Caliper Replacement . .

. . . . . . . . . . . . . 5A2-6
Rebuilding
the Caliper . . . . . . . . . . . . . 5A2-8 Rear
Disc Brakes .................... 5A2-1 0
Brake
Pads Inspection ............. 5A2-1 0
Brake Pads Replacement ........... 5A2-1 0
Servicing the Rotor ............... 5A2-12
Caliper Replacement .............. 5A2-14
Rebuilding the
Caliper ............. 5A2-17
Parking Brakes . . . . . . . . . . . . . . . .
See Section SC
Main Data and Specifications ........... 5A2-19
General Specifications ............... 5A2-19
Torque Specifications
............... 5A2-19
GENERAL DESCRIPTION
The disc brake assembly consists of a caliper, piston,
rotor, pad assembly and
support bracket. The caliper
assembly has a single bore and is mounted to the
support bracket with 2 mounting bolts. The support
bracket allows the caliper to move laterally against the
rotor. The
caliper is a one-piece casting with the
inboard side containing the piston bore. A square cut
rubber
seal is located in a groove in the piston bore
which provides the hydraulic seal between the piston
and the cylinder
wall.
NOTE:
• Replace all components included in repair kits
used
to service this caliper.
• Lubricate rubber parts with clean brake fluid to
ease assembly.
• If any hydraulic component is removed or
disconnected, it may be necessary to bleed all or
part of the brake system.
• Replace pads in axle sets only.
•
The torque values specified are for dry,
unlubricated fasteners.
• Perform service operation a clean bench free
from all mineral oil materials.
OPERATION
Hydraulic pressure, created by applying the brake
pedal, is converted by the caliper to a stopping force.
This force acts
equally against the piston and the
bottom of the caliper bore to move the piston outward
and to move (slide) the caliper inward resulting in a
clamping action on the rotor. This clamping action
forces the
linings against the rotor, creating friction to
stop the vehicle.

5A3-6 REAR WHEEL ANTILOCK BRAKE SYSTEM
SYSTEM DIAGRAM
4WD
switch
To 4WD
light -----11~-----lGY 3
Diagnostic Of------0 7 connector
For test
1-----11---+--y 17 Speed
sensor 1-----lt-----L
16
To
stoplight -----,
Stoplight switch
•IJI-----B 15
EBCM Pin View
i
&l ~ IU _, :;) Q
~ _, 0 a: .... z
8 IU ~ c( a: liD (.) z 0 a: 1-(.) IU _, IU
Pressure differential warning switch
(at Combination valve)
r-----+-<1 ~+II•
I•
6 LgB Parking brake _.-MI ____ ___,I'\.JI.Jr-, switch
5
BP -----'
2 w ------------~~._~
GR
4 BrR
9 BrY
20A Fuse F-9
RWAL 10
A •
1• h Fuse C-10
warnmg IQ t (Instrument
Antilock valve panel)
Isolation
valve
~ 4il .J o--1> ~
Reset ~1.5il
I
sw.
Dump valve
(Engine compartment)
13 YG - ACC IG1 Ignition
82 81 switch
50 A
Batt.
10 GW + ,,
15A BOA Fuse C-14 Main (Instrument fuse panel)
RWAL=Rear Wheel Antilock
CONNECTOR View
Fig. 5A3-6
•

REAR WHEEL ANTILOCK BRAKE SYSTEM 5A3-11
CHART B
Brake Light 110N" Rr. ABS Light "OFF' and Does Self Check
• START THE ENGINE, AND CHECK FOR BRAKE LIGHT.
• RELEASE PARKING BRAKE IF APPLIED.
J
I
I BRAKE LIGHT GOES OFF. J BRAKE LIGHT REMAINS ON.
I
I DISREGARD FAILURE. J • DISCONNECT THE PARKING BRAKE SWITCH CONNEC-
TOR FROM THE SWITCH, AND RECHECK FOR BRAKE LIGHT.
I
I
I BRAKE LIGHT GOES OFF. I BRAKE LIGHT REMAINS ON.
I I ADJUST OR REPLACE PARKING BRAKE SWITCH, AND J • DISCONNECT THE PRESSURE DIFFERENTIAL WARNING RECHECK IT.
SWITCH CONNECTOR
FROM THE SWITCH, AND RECHECK FOR BRAKE LIGHT.
I
I
I BRAKE LIGHT GOES OFF. I BRAKE LIGHT REMAINS ON.
j
I CHECK COMBINATION VALVE. REFER TO "HYDRAULIC I • DISCONNECT THE EBCM HARNESS CONNECTOR FROM
BRAKES" (SEC. 5A) FOR DIAGNOSIS.
EBCM, AND RECHECK FOR BRAKE LIGHT.
I
I
I BRAKE LIGHT GOES OFF. I BRAKE LIGHT REMAINS ON.
I
I REPLACE EBCM, AND RECHECK IT. I CHECK FOR SHORT TO GROUND IN BRAKE LIGHTWIRE,AND
REPAIR AND RECHECK THE SELF CHECK.
EBCM
= Electronic Brake Control Module

4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-5
DIAGNOSIS
GENERAL INFORMATION
ABS troubles can be classified to two types, those
which can be detected by the ABS warning light
and those which can be detected as a vehicle
abnormality by the driver.
In either case, locate the fault in accordance with
the "BASIC DIAGNOSTIC FLOWCHART" and repair.
Please refer to Section 5A, 5A1, 5A2, 5C for the
diagnosis
of mechanical troubles such as brake
noise, brake
judder (brake pedal or vehicle vibration
felt when braking), uneven braking, and parking
brake
trouble.
ABS SYSTEM SERVICE PRECAUTIONS
Required Tools and Items
Box Wrench
• Brake Fluid
Special Tool
Some diagnosis procedures in this section require
the installation of a special tool.
PINOUT BOX
In order to prevent damage to the 35-pin Electronic
Brake
Control Module (EBCM) connector, J-35592
pinout box should be installed on the EBCM
connector prior to probing any circuit with the
digital
multimeter. This pinout box is to be used
combined with J-35616 connector test adapter kit.
W IMPORTANT
Do not probe the 35-pin EBCM connector
without installing J-35592 pinout box. Damage
to connector terminals may occur if the pinout
box is not installed, resulting in improper
system operation. The following procedure
should be used to install J-35592 pinout box.
1. Ignition must be "OFF" when installing or
removing the 35-pin EBCM connector.
Fig. 5A4-3
2. Disconnect the 35-pin EBCM harness connector
by depressing the connector locking plate and
rotating
the connector toward the front of
vehicle.
3. Inspect the 35-pin connector for damage.
Connect J-35592 to the 35-pin connector.
4. Proceed with test as outlined in the diagnostic
procedure.
J-39200 HIGH IMPEDANCE MUL TIMETER
When circuit measurements are requested, use a
circuit tester
with high impedance.
COMPUTER SYSTEM SERVICE
PRECAUTIONS
The Antilock Brake System interfaces directly with
the Electronic Brake Control Module (EBCM) which
is a
control computer that is similar in some
regards
to the Engine Control Module. These
modules are designed to withstand normal current
draws associated with vehicle operation. However,
care
must be taken to avoid overloading any of the
EBCM circuits. In testing for opens or shorts, do not
ground or apply voltage to any of the circuits unless
instructed to
do so by the appropriate diagnostic
procedure. These circuits should only be tested
with a high impedance multimeter (J-39200) or
special tools as described in this section. Power
should never be removed or applied to any control
module with the ignition in the "ON" position.
Before removing
or connecting battery cables,
fuses
or connectors, always turn the ignition switch
to the "OFF" position.
GENERAL SERVICE PRECAUTIONS
The following are general precautions which should
be observed when servicing and diagnosing the
Antilock Brake System and/or
other vehicle
systems. Failure
to observe these precautions may
result in Antilock Brake System damage.
If welding work is to be performed on the
vehicle using an electric arc welder, the EBCM
and valve block connectors should be
disconnected before the
welding operation
begins.
The
EBCM and valve block connectors should
never be connected or disconnected with the
ignition "ON".
Hydraulic units of the Antilock Brake System
are not separately serviceable and must be
replaced
as assemblies. Do not disassemble
any
component which is designated as non­
serviceable in
this Section.

4-WHEEL ANTILOCK BRAKE SYSTEM (ABS) 5A4-31
MODE F6: WHEEL SENSORS
When conducting the wheel sensor test, note the following:
1) Accelerate vehicle only slightly above 20 km/h (12 mph).
2) When this speed is attained, put transmission into neutral and allow vehicle to coast to a halt. (Parking
brake may be engaged slightly.)
3) When vehicle is at a standstill, actuate either foot brake or parking brake.
When the
wheel speed sensor test is being performed, the output or speed value of all four sensors is
monitored
by TECH 1. When the output of wheel sensors becomes too low to convert into speed value, the
last known vehicle speed is displayed and the values are fixed. If wheel sensors are normal, it is at the
vehicle speed
of 5 km/h (3 mph) or less that their output is lost. Therefore, if all the fixed speed values are
less than 5 km/h (3 mph), the wheel sensors are normal. If one or more of the four speed values is more
than 5 km/h
(3 mph), it suggests that the following abnormalities have occurred to the sensor(s):
1. Excess gap between the sensor and sensor rotor.
2. Broken or damaged sensor rotor teeth.
3. Momentary open in sensor harness.

5A4-32 4-WHEEL ANTI LOCK BRAKE SYSTEM (ABS)
TECH 1 Display Key Operation
INSTRUCT I ON: This explains MODE F6.
DRIVE VE-Drive vehicle at 20 km/h (12 mph).
HICLE AT 20km/h Press the YES key for the next display.
AND THEN (YES)
RELEASE GAS Release accelerator pedal while driving, and put transmission into neutral.
PEDAL, DISENGAGE Press the YES key for the next display.
TRANSMISSION
AND (YES)
AS SOON AS THE After coasting to a halt with transmission in neutral, apply brakes
VEHICLE HAS immediately.
STOPPED APPLY Press the YES key for the next display.
BRAKES (YES) This completes instructions as to F6.
The test will be started with the next display.
BEGIN TEST Let's begin the test.
DRIVE VE-Carry out the test according to the display.
HICLE AT 20km/h ** indicates the wheel speed value into which the output of each sensor ** ** ** ** has been converted.
Decelerate vehicle by coasting until it comes to a halt. (Parking brake may
DECREASE VEHICLE be slightly engaged.)
SPEED TO Okm/h
** ** ** **
MEASURED WHEEL Make sure that there is no significant difference among the wheel speed
SPEED THRESHOLDS values.
** **
** ** The
data indicate 3-5 km/h (2-3 mph).
SEE CHART 6 (YES) See CHART 6 .. Refer to CHART C-2 for check procedure.
To obtain mph in
MODE: F6, display mph in MODE: FO once and thereafter, change to MODE:F6.