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Isuzu N-Series. Manual - part 233

HYDRAULIC BRAKES 5A-91

Master Cylinder Assembly (NKR / NPR / NQR / NPS)

Legend

1. Holder plate

13. Primary piston

2. Hose joint

14. Plug and O-ring

3. O-ring

15. Supporter

4. Primary piston assembly

16. Secondary piston assembly

5. Plug and O-ring

17. Primary cup

6. Secondary cup

18. Bushing

7. Bushing

19. O-ring

8. Primary cup

20. Secondary cup

9. Supporter

21. Screw

10. Screw

22. Spring retainer

11. Spring retainer

23. Secondary piston spring

12. Primary piston spring

24. Secondary piston

N5A0275E

5A-92 HYDRAULIC BRAKES

Disassembly

1. Holder Plate
2. Hose Joint
3. O-ring
4. Primary Piston Assembly

Draw out Piston by hand so that it may not be dam-
aged.

5. Plug and O-ring

Install master cylinder on a support plate (1), fix the
support in a vice, and loosen plug using a wrench
(2).
Support plate : 5-8840-2371-0
Wrench : 5-8840-2370-0
(Master cylinder inside diameter 31.7 mm, 30.1
mm)
Wrench : 5-8840-2369-0
(Master cylinder inside diameter 28.5 mm)
Wrench : 5-8840-2805-0
(Master cylinder inside diameter 34.9 mm)

6. Secondary Cup
7. Bushing
8. Primary Cup
9. Supporter

10. Screw
11. Spring Retainer
12. Primary Piston Spring
13. Primary Piston
14. Plug and O-ring

15. Supporter
16. Secondary Piston Assembly
17. Primary Cup
18. Bushing
19. O-ring
20. Secondary Cup
21. Screw
22. Spring Retainer
23. Secondary Piston Spring
24. Secondary Piston

Inspection and Repair

Make the necessary adjustments, repairs, and part re-
placements if excessive wear or damage is discovered
during inspection.

N5A0276E

N5A0277E

N5A0278E

HYDRAULIC BRAKES 5A-93

Cup and O-ring

1. Wash each part with brake oil and check for wear,

deterioration, and damage.

2. Replace the cups and O-rings.

Reassembly

1. Secondary Piston
2. Secondary Piston Spring
3. Spring Retainer
4. Screw
5. Secondary Cup
6. Bushing

Combine secondary cup and bushing with second-
ary piston as indicated as arrows, and push the as-
sembly in until bushing comes into contact with
cylinder body step.

7. O-ring

Install the O-ring to the bushing.

8. Primary Cup
9. Supporter

10. Plug and O-ring

Combine primary cup and supporter with plug as
indicated by arrows.

Then tighten plug to specified tightening torque.

Support plate : 5-8840-2371-0
Wrench : 5-8840-2370-0
(Master cylinder inside diameter 31.7 mm, 30.1
mm)
Wrench : 5-8840-2369-0
(Master cylinder inside diameter 28.5 mm)
Wrench : 5-8840-2805-0
(Master cylinder inside diameter 34.9 mm)

Notice:
If plug tightened to specified torque is found floating
from cylinder body, plug should be disassembled again
and check for abnormal parts fitting. Then reassemble.

N5A0281E

Plug Torque

⋅m (kg⋅m/lb⋅ft)

Master Cylinder
Inside diameter
(mm)

28.5

40 (4.1/30)

30.1

44 (4.5/33)

31.7

34.9

49 (5.0/37)

N5A0282E

5A-94 HYDRAULIC BRAKES

11. Primary Piston
12. Primary Piston Spring
13. Spring Retainer
14. Screw
15. Supporter
16. Primary Cup
17. Bushing

1) Combined the parts of primary piston as indi-

cated by arrows.
Then push the assembly in until bushing comes
into contact with the step in cylinder body.

2) Draw out primary piston alone taking care not

to be let bushing get out of the step.

18. Secondary Cup
19. Plug and O-ring

Combine secondary cup with plug as indicated by
arrow, and tighten to specified tightening torque.

Notice:
If plug tightened to specified torque is found floating
from cylinder body, plug should be disassembled again
and check for abnormal parts fitting. Then reassemble.
20. O-ring
21. Hose Joint
22. Holder Plate

N5A0283E

N5A0284E