Isuzu N-Series. Manual - part 227

HYDRAULIC BRAKES 5A-67

2) L.S.V adjustment

When the adjustment cannot be done with the
L.S.V spring shackle, loosen the L.S.V adjust
nut (2 pcs.) and adjust the oil pressure to the
standard value by sliding the L.S.V up and
down. After the L.S.V adjustment, readjust the
length of the L.S.V spring shackle.

Tighten:
L.S.V adjust nut to 13 N

⋅m (1.3 kg⋅m / 113 lb⋅in)

3. Unit Inspection of L.S.V

1) Loosen the L.S.V adjust nut (2 pcs.). And then

lift the L.S.V up fully and tighten it up tentatively
so that the L.S.V spring will not move.

2) Under the same conditions as 1) above, check

the rear wheel cylinder fluid pressure.

For (C) and (D), refer to the adjustment standard
table.

Legend

1. L.S.V spring shackle
2. Adjust nut
3. Lock nut

Legend

1. L.S.V adjust nut
2. L.S.V spring
3. L.S.V

N5A0226E

N5A0227E

Legend

1. L.S.V adjust nut
2. L.S.V spring
3. L.S.V

Standard

Master cylinder fluid 

pressure

kPa (kg/cm

2

/psi)

Rear fluid pressure

kPa (kg/cm

2

/psi)

2942 (30 / 427)

(C)

7845 (80 / 1138)

(D)

N5A0228E

5A-68 HYDRAULIC BRAKES

Adjustment Standard Table

N5A0225E

Models

(A) N (kg/lb)

(B) kPa (kg/cm

2

/psi)

(C) kPa (kg/cm

2

/

psi)

(D) kPa (kg/cm

2

/

psi)

NHR55-1C

5884(600/1323)

3687

±588

(37.6

±6/535±85)

1442

±196

(14.7

±2/209±28)

1932

±343

(19.7

±3.5/280±50)

NHR55-3C

8826(900/1984)

NKR77-1D

12258(1250/2756)

NKR77-5D

11768(1200/2646)

NKR77-3E

6865(700/1543)

NKR77-5E

8826(900/1984)

NKR77-5H

8826(900/1984)

NKR55-1E

6865(700/1543)

NKR55-3E

6865(700/1543)

NKR55-5H

9807(1000/2205)

5031

±588

(51.3

±6/730±85)

1697

±196

(17.3

±2/246±28)

2922

±343

(29.8

±3.5/424±50)

NKR77-3EXY (Taiwan)

6865(700/1543)

3687

±588

(37.6

±6/535±85)

1442

±196

(14.7

±2/209±28)

1932

±343

(19.7

±3.5/280±50)

NKR77-3EXA (Taiwan)

7845(800/1764)

NKR77-5E (Taiwan)

9807(1000/2205)

NKR77-5H (Taiwan)

9807(1000/2205)

5031

±588

(51.3

±6/730±85)

1697

±196

(17.3

±2/246±28)

2922

±343

(29.8

±3.5/424±50)

NPR77-5D/5CW

11768(1200/2646)

3687

±588

(37.6

±6/535±85)

1442

±196

(14.7

±2/209±28)

1932

±343

(19.7

±3.5/280±50)

HYDRAULIC BRAKES 5A-69

Deceleration Sensing Proportioning Valve

DSPV Mounting Angle

Conduct the following inspections, and if any abnormality is found, replace.

NPR75-5E

8826(900/1984)

5031

±588

(51.3

±6/730±85)

1697

±196

(17.3

±2/246±28)

2922

±343

(29.8

±3.5/424±50)

NPR77-5H

8826(900/1984)

NPR70/75-5J/5HW

14710(1500/3307)

NPR75-5J/5HW

14710(1500/3307)

NPR70/75-5L/5KW

16671(1700/3748)

NQR75-5L/5KW

14710(1500/3307)

NQR75-5N (Australia)

12749(1300/2866)

NPR66-5J

8826(900/1984)

NPR66-5E

15691(1600/3527)

NPR66-5L (South
Africa)

12749(1300/2866)

NPR66-5L (GCC)

13729(1400/3086)

NPR71 / NQR70-5L

13729(1400/3086)

NQR71-5N

13729(1400/3086)

NQR75-5N (South
Africa)

14710(1500/3307)

NPS71/75-5J

17652(1800/3968)

Legend

1. Mounting angle

3. Ground surface

2. Mounting surface

4. Front

Models

Mounting Angle

NHR

12

°00′±45′

NKR

12

°30′±45′

Models

(A) N (kg/lb)

(B) kPa (kg/cm

2

/psi)

(C) kPa (kg/cm

2

/

psi)

(D) kPa (kg/cm

2

/

psi)

N5A0230E

5A-70 HYDRAULIC BRAKES

Condition

Procedure

Judgement

As installed in the vehi-
cle

Measure braking force to make sure of 
normality.

If no braking force, adherence of ball 
(deceleration sensing) to seal is sus-
pected.

Bleed air also from the DSPV side of 
breather.

If no brake fluid does not come out, the 
same trouble as above is suspected.

Check fluid leakage.

No problem, if there is no leak.

Check mounting angle. (Refer to the 
table.)

If installed at an abnormal angle, though 
rare, specified braking force is unobtain-
able or DSPV does not work.

As not installed in the 
vehicle

Incline DSPV back and forth to see if the 
ball moves insides.

No problem, if a ball sound is heard from 
within.