Clutch Diagnosis

1
Clutch Diagnosis
2
Possible Problems

• Slipping
• Chatter
• No release
• Excessive effort
• Insufficient pedal travel
• Excessive pedal travel
• Harsh engagement
• Noise

3
Slipping

• Possible causes
• Normal wear
• Oil contamination
• Weak pressure plate
• Overloading
• Misadjusted linkage
• Diagnosis
• Lug the engine in high gear

4
Chattering

• Grabbing or jerking that occurs when starting out
  in low gear
• Possible causes
• Broken or deteriorated motor mounts
• Broken or deteriorated rear axle control arm
  bushings
• Burned or glazed clutch disc
• Worn clutch hub splines
• Warped pressure plate or flywheel
• Collapsed Marcel springs

5
No Release

• Possible Causes
• Improper linkage adjustment
• Loose linkage
• Binding between clutch disc hub and input shaft
• Bent or warped clutch disc
• Clutch disc installed backwards
• Seized pilot bearing
• Rusted clutch disc (long-term storage)

6
Excessive Effort

• Possible Cause
• Binding linkage or cable
• Obstructed or restricted hydraulic line
• High performance pressure plate installed
• Wrong release fork or linkage
• Lack of leverage

7
Insufficient Pedal Travel

• Possible causes
• Worn clutch
• Misadjusted linkage

8
Excessive Pedal Travel

• Possible causes
• Misadjusted Linkage
• Improperly bled hydraulic system
• Faulty master/slave cylinder

9
Harsh Engagement

• Possible Causes
• Oil contamination
• Flattened Marcel springs
• Broken torsional dampening springs

10
Noise

• The key to diagnosing noises is to understand
  what is turning against what when
• Example
• A worn pilot bearing should not make noise when
  the clutch is engages because the input shaft and
  the crankshaft are turning at the same speed in
  the same direction
• Possible sources of noise
• Pilot bearing
• Throwout bearing
• Input shaft bearing
• Linkages
• Release fork pivot ball

11
Noise Diagnosis
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Clutch Repair

• Transmission must be removed to repair clutch
• Bellhousing may be removable
• Always resurface flywheel
• May be stepped
• Height of steps is important
• Replace entire clutch assembly
• Disc
• Pressure plate
• Pilot bearing
• Throwout bearing

13
Flywheel Resurfacing
14
Flywheel Resurfacing