Isuzu N-Series. Manual - part 226

HYDRAULIC BRAKES 5A-63

Clevis and Lock Nut Replacement

Removal

1. Remove hydraulic booster assembly.

Refer to “Removal” of Hydraulic Booster in this
section.

2. Secure the hydro boost assembly to the jig using

the four stud bolts on the surface of the flange for
attachment to the vehicle.

3. Being careful not to exert any off-center load on the

operating rod, loosen the lock nut and remove the
clevis and lock nut.

Installation

1. Screw the lock nut and then the clevis onto the op-

erating rod.

2. Adjust so that the booster clevis position dimension

(the distance to the center of the clevis hole from
the surface of the flange for attachment to the ve-
hicle) is 109 

± 1 mm (4.29 ± 0.04 in), and tighten

the lock nut with the prescribed torque.
When tightening the lock nut, be careful not to de-
form the clevis.

Tighten:
Lock nut to 20 N

⋅m (2.0 kg⋅m / 14 lb⋅ft)

3. Attach the hydro boost assembly to the vehicle.

Refer to “Installation” of Hydraulic Booster in this
section.

Legend

1. Accumulator
2. Stud bolt
3. Cover boss
4. Lock nut
5. Clevis
6. Operating rod
7. Guard
8. Flange

N5A0010E

5A-64 HYDRAULIC BRAKES

Guard Replacement

Removal

1. Remove hydraulic booster assembly.

Refer to “Removal” of Hydraulic Booster in this
section.

2. Secure the hydro boost assembly to the jig using

the four stud bolts on the surface of the flange for
attachment to the vehicle.

3. Being careful not to exert any off-center load on the

operating rod, loosen the lock nut and remove the
clevis and lock nut.

4. Remove the guard from the cover boss anchoring

groove and from the operating rod anchoring
groove, and pull it out.

Installation

1. With a dry cloth, clean well the cover boss anchor-

ing groove and the operating rod anchoring
groove, and verify that no foreign matter is present.

2. Insert from the large diameter hole side of the

guard end-face into the operating rod outside di-
ameter part, assemble the small diameter hole part
of the guard end-face into the anchoring groove of
the operating rod, then assemble the large diame-
ter hole part securely into the anchoring groove of
the boss of the cover.

3. Screw the lock nut and then the clevis onto the op-

erating rod.

4. Adjust so that the booster clevis position dimension

(the distance to the center of the clevis hole from
the surface of the flange for attachment to the ve-
hicle) is 109

±1 mm (4.29 ± 0.04 in), and tighten the

lock nut with the prescribed torque. When tighten-
ing the lock nut, be careful not to deform the clevis.

Tighten:
Lock nut to 20 N

⋅m (2.0 kg⋅m / 14 lb⋅ft)

5. Attach the hydro boost assembly to the vehicle.

Refer to “Installation” of Hydraulic Booster in this
section.

Legend

1. Accumulator
2. Stud bolt
3. Cover boss
4. Lock nut
5. Clevis
6. Operating rod
7. Guard
8. Flange

N5A0010E

HYDRAULIC BRAKES 5A-65

Load Sensing Proportioning Valve

Removal

1. Nut
2. Washer
3. Load sensing Proportioning Valve
4. Bracket

Installation 

To install, follow the removal steps in the reverse order.

Adjustment 

1. Fluid Pressure Measurement

1) Rear axle weight adjustment

With an axle weight meter, adjust the rear axle
weight with a person sitting in the driver’s seat
and a weight loaded in the rear body.

For (A), refer to the adjustment standard table.

Legend

1. Nut

3. Load sensing proportioning valve

2. Washer

4. Bracket

N5A0220E

N (kg/lb)

Adjustment value

(A)

5A-66 HYDRAULIC BRAKES

2) Installation of a fluid pressure gauge

Remove the air bleeder of the left hand wheel
front and rear brakes. Bleed air out of the fluid
pressure gauge with the measurement hose of
the fluid pressure gauge installed.

Pressure Tester: Brake oil (Fluid pressure gauge)
5-8840-2190-0

3) Rear wheel cylinder fluid pressure measure-

ment
Step on the brake pedal until the fluid pressure
of the front wheel cylinder gets to 7845 kPa (80
kg/cm

2

 / 1138 psi), and check the rear wheel

cylinder fluid pressure. (Read the value of the
front wheel cylinder fluid pressure 2 seconds

after the measurement. When measuring the
L.S.V fluid pressure, keep the brake pedal
pressed down without stepping it down twice or
releasing it.)

For (B), refer to the adjustment standard table.

2. Oil Pressure Adjustment

1) L.S.V spring shackle adjustment

Loosen the adjust nut of the L.S.V spring
shackle, and adjust the length of the L.S.V
spring shackle.
When the oil pressure is insufficient, turn the
adjust nut clockwise to extend the span “A”.
When the oil pressure is too high, turn the ad-
just nut counterclockwise to reduce the span
“A”.

After adjustment, tighten the lock nut securely and install
the cotter pin.

Tighten:
Lock nut to Max. 10 N

⋅m (1.0 kg⋅m / 87 lb⋅in)

Legend

1. Weight
2. Platform (which is the same height as the axle 

weight meter)

3. Axle weight meter

N5A0223E

N5A0224E

Rear Wheel Cylinder Fluid Pressure

kPa (kg/cm

2

/

psi)

Standard

(B)

mm (in)

Item

Span adjusted

Standard of span “A”

78 (3.07)

Range adjustable

72 — 84 (2.83 — 3.31)

N5A0225E