Diagnosis Chart
The diagnosis charts describe common clutch problems, causes and correction. Refer to DIAGNOSIS CHART . Conditions, causes and corrective action are outlined in the indicated columns.
DIAGNOSIS CHART
| CONDITION | POSSIBLE CAUSES | CORRECTION |
|---|---|---|
| Disc facing worn out | 1. Normal wear. | 1. Replace cover and disc. |
| 2. Driver frequently rides (slips) the clutch. Results in rapid overheating and wear. | 2. Replace cover and disc. | |
| 3. Insufficient clutch cover diaphragm spring tension. | 3. Replace cover and disc. | |
| Clutch disc facing contaminated with oil, grease, or clutch fluid. | 1. Leak at rear main engine seal or transmission input shaft seal. | 1. Replace appropriate seal. |
| 2. Excessive amount of grease applied to the input shaft splines. | 2. Remove grease and apply the correct amount of grease. | |
| 3. Road splash, water entering housing. | 3. Replace clutch disc. Clean clutch cover and reuse if in good condition. | |
| 4. Slave cylinder leaking. | 4. Replace hydraulic clutch linkage. | |
| Clutch is running partially disengaged. | 1. Release bearing sticking or binding and does not return to the normal running position. | 1. Verify failure. Replace the release bearing and transmission front bearing retainer as necessary. |
| Flywheel below minimum thickness specification. | 1. Improper flywheel machining. Flywheel has excessive taper or excessive material removal. | 1. Replace flywheel. |
| Clutch disc, cover and/or diaphragm spring warped or distorted. | 1. Rough handling. Impact bent cover, spring, or disc. | 1. Replace disc or cover as necessary. |
| 2. Improper bolt tightening procedure. | 2. Tighten clutch cover using proper procedure. | |
| Facing on flywheel side of disc torn, gouged, or worn. | 1. Flywheel surface scored or nicked. | 1. Correct surface condition if possible. Replace flywheel and disc as necessary. |
| 2. Clutch disc sticking or binding on transmission input shaft. | 2. Lubricate splines with high temperature grease. | |
| Clutch disc facing burnt. Flywheel and cover pressure plate surfaces heavily glazed. | 1. Frequent operation under high loads or hard acceleration conditions. | 1. Correct condition of flywheel and pressure plate surface. Replace clutch cover and disc. Alert driver to problem cause. |
| 2. Driver frequently rides (slips) clutch. Results in rapid wear and overheating of disc and cover. | 2. Correct condition of flywheel and pressure plate surface. Replace clutch cover and disc. Alert driver to problem cause. | |
| 3. Contamination of clutch. | 3. Correct fluid leak. Replace clutch cover and disc. | |
| Clutch disc binds on input shaft splines. | 1. Clutch disc hub splines damaged during installation. | 1. Clean, smooth, and lubricate hub splines if possible. Replace disc if necessary. |
| 2. Input shaft splines rough, damaged, or corroded. | 2. Clean, smooth, and lubricate shaft splines if possible. Replace input shaft if necessary. | |
| Clutch disc rusted to flywheel and/or pressure plate. | 1. Clutch not used for and extended period of time (e.g. long term vehicle storage). | 1. Sand rusted surfaces with 180 grit sanding paper. Replace clutch cover and flywheel if necessary. |
| Pilot bearing seized, loose, or rollers are worn. | 1. Bearing cocked during installation. | 1. Install and lubricate a new bearing. |
| 2. Bearing defective. | 2. Install and lubricate a new bearing. | |
| 3. Bearing not lubricated. | 3. Install and lubricate a new bearing. | |
| 4. Clutch misalignment. | 4. Inspect clutch and correct as necessary. Install and lubricate a new bearing. | |
| Clutch will not disengage properly. | 1. Low clutch fluid level. | 1. Replace hydraulic linkage assembly. |
| 2. Clutch cover loose. | 2. Follow proper bolt tightening procedure. | |
| 3. Clutch disc bent or distorted. | 3. Replace clutch disc. | |
| 4. Clutch cover diaphragm spring bent or warped. | 4. Replace clutch cover. | |
| 5. Clutch disc installed backwards. | 5. Remove and install clutch disc correctly. | |
| 6. Release fork bent or fork pivot loose or damaged. | 6. Replace fork or pivot as necessary. | |
| 7. Clutch master or slave cylinder failure. | 7. Replace hydraulic linkage assembly. | |
| Clutch pedal squeak. | 1. Pivot pin loose. | 1. Tighten pivot pin if possible. Replace clutch pedal if necessary. |
| 2. Master cylinder bushing not lubricated. | 2. Lubricate master cylinder bushing. | |
| 3. Pedal bushings worn out or cracked. | 3. Replace and lubricate bushings. | |
| Clutch master or slave cylinder plunger dragging and\or binding | 1. Master or slave cylinder components worn or corroded. | 1. Replace clutch hydraulic linkage assembly. |
| Release bearing is noisy. | 1. Release bearing defective or damaged. | 1. Replace release bearing. |
| Contact surface of release bearing damaged. | 1. Clutch cover incorrect or release fingers bent or distorted. | 1. Replace clutch cover and release bearing. |
| 2. Release bearing defective or damaged. | 2. Replace the release bearing. | |
| 3. Release bearing misaligned. | 3. Check and correct runout of clutch components. Check front bearing sleeve for damage/alignment. Repair as necessary. | |
| Partial engagement of clutch disc. One side of disc is worn and the other side is glazed and lightly worn. | 1. Clutch pressure plate position incorrect. | 1. Replace clutch disc and cover. |
| 2. Clutch cover, spring, or release fingers bent or distorted. | 2. Replace clutch disc and cover. | |
| 3. Clutch disc damaged or distorted. | 2. Replace clutch disc. | |
| 4. Clutch misalignment. | 4. Check alignment and runout of flywheel, disc, pressure plate, and\or clutch housing. Correct as necessary. |