2004 ISUZU TF SERIES engine

5C-20 BRAKES







Operation

The operation of the P-valve by the master cylinde
r
pressure is unchanged up to the brake points
A and B.
If master cylinder fluid pressure penetrates into the second
break point
B, the fluid pressure pressing against the seal
2, (which isolated route 4 and route 5), passing the route
4of the master cylinder side, overcomes the operating
force of the spring
3 + fluid pressure affecting the seal 2of
the wheel cylinder, and presses the piston
1to the right
side, resulting in the opening of the routes
4 and 5, and
canceling of the P-valve operation.
Then, because the master cylinder fluid pressure and the
wheel cylinder fluid pressure, up to the point
C, operate on
the identical surface of the seal
2, both have identical
ascending ratio.
However, because of the operation of spring
3 in the wheel
cylinder side, wheel cylinder fluid pressure operate to
preserve the balance against the master cylinder fluid
pressure on the lower level with the difference in pressure
resulting from this spring.
03260002-2


Valve Maintenance
In the case of fluid leak or other abnormalities, faulty valve
should be replaced.
The valve is set up at the engine room.
Note:
The blend proportioning valve is not repairable and must
be replaced as a complete assembly.

BRAKES 5C-25


Filling Master Cylinder Reservoir
CAUTION :
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 fluid 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.
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. Thoroughly clean reservoir cap before removal
to avoid getting dirt into reservoir. Add fluid as required to
bring level to the “MAX” mark on the reservoir tank. Use
“DOT 3” Hydraulic Brake Fluid.

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, leakage
from the hydraulic pressure system is possible.
Make sure by visual check that there is no leak.




BLEEDING OF THE BRAKE HYDRAULIC
CIRCUIT
If air enters the bake lines, it will cause poor brake action.
Therefore, bleeding should be performed if the brakes have
been used with the level of brake fluid in the reservoir
excessively low or if brake pipes have been disconnected in
the course of brake servicing.
Bleeding operation calls for co-operative action of 2 persons.

Set the parking brake firmly while bleeding.

Perform bleeding operation with ENGINE RUNNING, to
prevent damage to push rod seal.

Make sure exhaust is suitably ventilated.

Bleed the hydraulic system with the fluid reservoir filled to
the specified level.

Bleed the system starting with the rear wheel cylinde
r
farthest from the master cylinder.

5C-26 BRAKES


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 disconnected at one wheel, only that
wheel cylinder/caliper needs to be bled. If the pipes are
disconnected at any fitting located between the master cylinder
and brakes, then the brake system served by the disconnected
pipe must be bled.

1. 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.
2. Remove the master cylinder reservoir cap.

3. Fill the master cylinder reservoir with brake fluid. Keep the
reservoir at least half full during the air bleeding operation
4. Always use new brake fluid for replenishment.
5. In replenishing rake fluid, take care that air bubbles do no
t
enter the brake fluid.


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


Bleeding the Master Cylinder
6. 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.
7. Depress the brake pedal slowly once and hold it depressed.
8. Completely seal the delivery port of the master cylinder with
your finger, where the pipe was disconnected then release
the brake pedal slowly.
9. Release your finger from the delivery port when the brake
pedal returns completely.
10. Repeat steps 7 through 9 until the brake fluid comes out o
f
the delivery port during step 7.
NOTE : Do not allow the fluid level in the reservoir to go below
the half-way mark.
11. Reconnect the brake pipe (1) to the master cylinder and
tighten the pipe.
12. Depress the brake pedal slowly once and hold it depressed.
13. Loosen the rear wheel brake pipe (1) at the master cylinder.
14. Retighten the brake pipe, then release the brake pedal
slowly.

5C-28 BRAKES


27. 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 “MAX" level as necessary.
28. Attach the reservoir cap.
29. Stop the engine.




05007-1


BRAKE LINE (HOSES AND PIPES)

Inspect all hoses and pipes for wear, bending, chafing,
cracks, dents, or any other damage.
Make necessary correction or parts replacement if these
abnormal conditions are found through inspection.

All hoses, pipes and joints can be damaged easily.
Do not allow the hose to become excessively twisted and
bent when working with then, and pay special attention to all
the brake lines not to damage them when repairing o
r
replacing other parts (axle, suspension, etc).

Inspection for leakage should be performed by depressing
the brake pedal fully.
If leakage is apparent at the circumference of joints,
retighten or replace these parts.
This procedure must be performed whenever brake lines
are installed.

After disconnecting the hoses and pipes, cap or tape the
openings to prevent entry of foreign material.

BRAKES 5C-31

ADJUSTMENT PROCEDURE OF BRAKE PEDAL



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

RTW35CSH000601


Brake Pedal - Height
Measure the brake pedal height after making sure the pedal is
fully returned by the pedal return spring.
Note:
Pedal height (L2) must be measured after starting the
engine and increasing the revolution several times by
stepping on the accelerator pedal.
mm(in)

Pedal free play (L1) 6-10 (0.23 - 0.39)
M/T 174-186 (6.85-7.32)
RHD
LHD
A/T 176-188 (6.93-7.40) Height (L2)
Note:
Pedal free play must be measured after turning off the
engine and stepping on the brake pedal firmly five times
or more.
If the measured value deviates from the above range, adjust
the brake pedal as follows:
a) Disconnect the stop lamp switch.
b) Loosen the lock nut on the push rod.
c)
Adjust the brake pedal to the specified height by rotating the
push rod in the appropriate direction.



Lock Nut Torque N

m(kgf

m/lb
 
ft)
12 - 18 (1.2 – 1.8 / 9 - 13)

d) Install the stop lamp switch.

Note:
Pedal height (L
2) must be 80 mm (3.14 in.) or more when
applying about 50 kg (110.25 lbs.) of stepping force.

331R300005


How to connect the CLEVICE of BOOSTER ROD with PEDAL
ARM. and how to adjust the PEDAL SW.
After connecting the CLEVIS of BOOSTER ROD with PEDAL
ARM, adjust the PEDAL SW mounted (PDA) to PEDAL
BRACKET by the procedure explained still more bellow.
1. Set the hole of the CLEVIS of BOOSTER&M/CYL ROD
with the hole of the PEDAL ARM.
2. Enter the PIN; PUSH ROD to PEDAL to these holes
from left side of the PEDAL.
3. Enter and fix the PIN; SANP PIN FIX to the DITCH o
f
the PIN; PUSH ROD to PEDAL from right side of the
PEDAL.
4. Release the LOCK by turning the SWITCH counter-
clock-wise.

5C-60 BRAKES
Inspection and Repair
Vacuum Hose (The built in check valve)
360R300002


1) Inspect the check valve (2), which is installed inside the
vacuum hose.
2) Blow air into the hose from the booster side as shown in
the illustration. The air should pass freely through the
hose.
3) Blow air into the hose from the engine side. The check
valve should close to block the passage of air.
The vacuum hose and built-in check valve must be
replaced as a set if either is found to be defective.

Important Operation-Installation
8. Vacuum Booster Assembly
7. Vacuum Booster Fixing Nut
6. Snap Pin
1) Perform vacuum booster and vacuum booster push rod
adjustment.
Note :
When replacing either the master cylinder or vacuum booster,
be sure to measure push rod, and adjust if required.

RTW35CSH000901

2) Measure the dimension (B) of master cylinder.


3) Apply negative pressure by means of vacuum pump so
that the pressure in the vacuum booster becomes
GASOLINE ENGINE: 66.7 kPa (500 mm Hg) or DIESEL
ENGINE 93.3 kPa (700 mm Hg).
Note :
Be sure to apply NEGATIVE pressure after installing a push
rod gauge on the vacuum booster.

BRAKES 5C-61


















4) Measure dimension (A)

RTW35CSH000801







5) Calculate the gap (B-A) when assembling the master
cylinder and vacuum booster.

GAP mm (in
)
0 
0.4 (0 
0.0157)



6) If dimension (A) is out of the standard range, adjust the
push rod.

Loosen the push rod lock nut (1) on the vacuum
booster.

Set the clevis (2).

Use the adjuster (3) to adjust the length of the
protruding portion of the push rod.

Vacuum (negative) pressure should be GASOLINE
ENGINE: 66.7 kPa (500mm Hg) or DIESEL
ENGINE: 93.3 kPa (700mm Hg) after adjustment.

Tighten the push rod lock nut to the specified torque.







Torque N

m(kgf

m/lb

ft)
18 – 25 (1.8 – 2.5 / 13 – 18)

7) Install the vacuum booster assembly to the dash panel
and pedal mounting bracket.
Torque N

m(kgf

m/lb

ft)
18 – 24 (1.8 – 2.4 / 13 – 17)

5C-62 BRAKES
360r300003
5. Vacuum Hose
The check valve (2) is built-in to the vacuum hose.
When installing the vacuum hose make sure that the arrow on
the hose is facing the engine (1).
Note :

Do not apply oil to the vacuum hose.



Installation direction is very important. The booster will no
t
operate if the vacuum hose is installed in the wrong
direction.


4JA1-T/4JA1-TC/4JH1-TC LHD model (with 2nd Battery)


RTW45CLF000101