Isuzu N-Series. Manual - part 864

CLUTCH 7C-5

Troubleshooting

Trouble

Cause

Treatment

Dragging

Hydraulic line leakage.

Repair.

Air in line.

Bleed air.

Master cylinder and/or slave cylinder seals worn.

Replace seals.

Driven plate worn or warped.

Replace.

Diaphragm spring weak or tip of finger worn.

Replace.

Driven plate sticking on spline.

Apply grease or replace.

Release bearing worn or damaged.

Replace.

Clutch pedal excessive free play.

Readjust.

Slippage

Driven plate facing worn or oil soaked.

Replace.

Diaphragm spring weak.

Replace.

Pressure plate and/or flywheel warped.

Repair or replace.

Clutch pedal lack of free play.

Readjust.

Shudder (Chattering)

Engine mounting loose or broken.

Tighten or replace.

Driven plate facing warped.

Replace.

Driven plate surface of facing hardened.

Replace.

Driven plate facing oil soaked.

Replace and check oil leakage.

Driven plate damper spring weakened or broken.

Replace.

Pressure plate and/or flywheel warped.

Repair or replace.

Noisy

Release bearing binding.

Repair or replace, apply grease.

Release bearing worn or broken.

Replace.

Release bearing insufficiently lubricated.

Replace.

Driven plate damper springs weakened or broken.

Replace driven plate.

Pilot bearing worn or broken.

Replace.

Driven plate rivet loosened.

Replace driven plate.

Ball stud insufficiently lubricated.

Lubricate with grease.

Clutch pedal lack of free play.

Readjust.

Clutch pedal shaft insufficiently lubricated.

Repair or replace.

Pedal is Hard to Push

Hydraulic line blocked or crimped.

Clean out or replace.

Clutch booster malfunction.

Repair or replace.

Clutch pedal shaft insufficiently lubricated.

Repair or replace.

7C-6 CLUTCH

ON-VEHICLE SERVICE

Clutch Assembly

Components

Removal

1. Remove the transmission assembly from the vehi-

cle.

• Refer to TRANSMISSION ASSEMBLY.

2. Remove the pressure plate assembly.
3. Remove the driven plate assembly.

• Use pilot aligner 5-8840-2790-0 to prevent the

driven plate assembly from falling.

• Mark the flywheel and clutch cover for align-

ment when installing.

Legend

1. Driven plate assembly

4. Transmission assembly

2. Pressure plate assembly

5. Shift fork

3. Release bearing assembly

N7A0486E

N7A0487E

CLUTCH 7C-7

4. Remove the release bearing.
5. Remove the shift fork.

Inspection

Make the necessary adjustment, repairs, and part re-
placement if excessive wear or damage is found during
inspection.
Pressure Plate Assembly

• Visually inspect the pressure plate friction surface

for excessive wear and heat cracks. If excessive
wear or deep heat cracks are present, the pressure
plate assembly must be replaced.

Pressure Plate Warpage

• Use a straight gauge and a filler gauge to measure

the pressure plate friction surface flatness in four
directions.
If any of the measured values exceed the specified
limit, the pressure plate assembly must be re-
placed.

Pressure Plate Warpage
Limit : 0.3 mm (0.012 in)
Clutch Cover

• Visually inspect the entire clutch cover for exces-

sive wear, cracking, and other damage. The pres-
sure plate assembly must be replaced if any of
these conditions are present.

Clutch Set Force

1. Invert the pressure plate.
2. Place on the pressure plate, a new clutch disk, or

a spacer of 8.5 mm (0.33 in) in place of the clutch
disk.

3. Compress the pressure plate assembly until the di-

mension becomes 19 mm (0.748 in).

4. Note the pressure plate gauge reading.

Diaphragm Spring Finger Height

1. Place a spacer of 8.5 mm (0.33 in) under the pres-

sure plate.

N7A0488E

Clutch Set Force : 

Set Force

Engine Model

8,340 N (850 kg / 1,874 lb)

4HF1, 4HG1, 4HF1-II

9,500 N (970 kg / 2,139 lb)

4HG1-T, 4HE1-TC-N, 

4HK1-TC

6,200 N (633 kg / 1,396 lb)

4JH1-TC-S

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N7A0490E

7C-8 CLUTCH

2. Compress the pressure plate assembly and the di-

aphragm spring until the distance “B” becomes
specified. There are two ways to do this.
a. Use a bench press to press down on the pres-

sure plate assembly from the top.

b. Tighten the pressure plate assembly fixing

bolts.

3. Measure the distance between the base and the

top of the diaphragm spring.

Spring Finger Height
Standard : 49.0 — 51.0 mm (1.929 — 2.008 in)

Driven Plate Assembly

• Visually inspect the torsion spring for looseness,

breakage, and weakening. If any of these condi-
tions are found, the driven plate assembly must be
replaced.

• Visually inspect the facing surfaces for cracking

and excessive scorching.

• Visually inspect the facing surfaces for the pres-

ence of oil or grease. If any of these conditions are
found, the facing must be cleaned or the driven
plate assembly replaced.

• Check that the driven plate moves smoothly on the

transmission top gear shaft spline. Minor ridges on
the top gear shaft spline may be removed with an
oil stone.

Driven Plate Warpage

1. Insert pilot aligner 5-8840-2790-0 into the driven

plate spline hub. The pilot aligner must be held per-
fectly horizontal.

2. Set a dial indicator to the driven plate outside cir-

cumference.

3. Slowly turn the driven plate, and read the dial indi-

cator.

4. If the measured value exceeds the specified limit,

replace the driven plate assembly.

Driven Plate Warpage
Standard : 0.7 mm (0.028 in) or less
Limit : 1.0 mm (0.039 in)

Driven Plate Spline Free Play

1. Install the driven plate to the transmission top gear

shaft spline.

2. Set a surface gauge to the driven plate outside cir-

cumference.

3. Slowly turn the driven plate. Measure the spline ro-

tation free play.

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