| Diagnosis and Testing Clutch Since troubleshooting actually begins when repairs are taken on, the following procedure is recommended: - Check customer concern is clear. If necessary, reconstruct the concern on the vehicle.
- If the concern cannot be reconstructed, road test the vehicle and/or carry out a visual check as described in the following table:
Visual Inspection Chart | Mechanical | - Oil leaks from the transmission.
- Visibly damaged or worn parts.
- Loose or missing screws or nuts.
| - If the fault can be clearly identified during the course of the visual check, rectify it and check that the system operates properly.
- If the fault cannot be clearly identified, use the following Symptom Chart to identify it exactly.
Clutch Controls Since troubleshooting actually begins when repairs are taken on, the following procedure is recommended: - Check customer concern is clear. If necessary, reconstruct the concern on the vehicle.
- If the concern cannot be reconstructed, road test the vehicle and/or carry out a visual check as described in the following table:
- If the fault can be clearly identified during the course of the visual check, rectify it and check that the system operates properly.
- If the fault cannot be clearly identified, use the following Symptom Chart to identify it exactly.
Visual Inspection Chart | Mechanical | - Clutch operation - oil leaks.
- Visibly damaged or worn parts.
- Loose or missing bolts or nuts.
| Symptom Chart - Clutch Symptom Chart | Symptom | Possible Sources | Action | | Clutch slips | * Insufficient clutch pedal play * Clutch pedal movement restricted (floor covering underneath the pedal). * Stiff clutch pedal. * Clutch pedal travel does not match specifications. * Hardened or oily clutch discs. * Worn clutch discs. * Damaged clutch pressure plate. * Damaged or weak diaphragm springs. * Damaged flywheel. | * GO TO System Test A | | Clutch snatches | * Loose or worn engine or transmission mountings. * Damaged diaphragm spring. * Damaged clutch pressure plate. * Overheated friction surface on clutch disc. * Damaged flywheel. * Grease or oil on the clutch disc. | * GO TO System Test B | | Clutch does not disengage | * Air in the hydraulic clutch system. * Excessive clutch pedal play * Corroded or worn clutch disc splines. * Friction material has come away from clutch plate. | * GO TO System Test C | | Clutch pedal vibrates | * Faulty diaphragm spring * Flywheel run-out | * GO TO System Test D | | Unusual noises | * Damaged clutch release bearing * Excessive crankshaft end float. | * GO TO System Test E | Symptom Chart - Clutch Operation Symptom Chart | Symptom | Possible Sources | Action | | Clutch does not disengage | * Air in the hydraulic clutch system. | * | | * Brake fluid level too low. | * Top up brake fluid. | | * Clutch pedal travel does not match specifications. | * | | Hydraulic clutch operation system leaking. | * Leaking clutch master cylinder. * Clutch slave cylinder leaking. * Leaking hydraulic clutch pipes. | * GO TO System Test F | System Test - Clutch | PINPOINT TEST A : | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | A1: TEST CLUTCH SLIP | | | 1 Lock wheels and apply parking brake. | | | 2 Ignition switch in position III. | | | 3 Start the engine and engage fourth gear. Keep the clutch pedal depressed. | | | 4 Run the engine at approx. 2000 rev/min. | | | 5 Slowly release the clutch pedal, and at the same time try to maintain the engine speed. | | | Does the engine stall when the clutch pedal is fully released? Yes Clutch OK. No | | A2: CHECK THE CLUTCH PEDAL PLAY | | | 1 Operate clutch pedal manually to the point of resistance and release. | | | 2 Measure the clutch pedal play. | | | Is the play between 1 - 3 mm? Yes No | | A3: TEST CLUTCH PEDAL | | | 1 Check lubrication. | | | Is the clutch pedal pivot shaft sufficiently lubricated? Yes No Lubricate the clutch pedal pivot shaft with high-temperature grease (ESD-M1C220-A). | | A4: CHECK THE CLUTCH PEDAL TRAVEL | | | 1 Depress the clutch pedal by hand until it reaches the lower stop and then release it. | | | 2 Measure the pedal travel. | | | Is the measured pedal travel 125 ± 3 mm? Yes No | System Test - Clutch | PINPOINT TEST B : | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | B1: TEST CLUTCH SNATCH | | | 1 Ignition switch in position III. | | | 2 Start engine and engage first gear. Keep the clutch pedal depressed. | | | 3 Run the engine at between 1200 rev/min and 1500 rev/min. | | | 4 Release clutch pedal slowly. | | | Does the vehicle jerk when it starts off? Yes No Clutch OK. | | B2: TEST ENGINE AND TRANSMISSION MOUNTINGS | | | 1 Check engine and transmission mountings for damage or loosened bolts. | | | Are the engine or transmission mountings loose or damaged? Yes Tighten bolts and/or RENEW damaged engine mountings. No | | B3: TEST CLUTCH PRESSURE PLATE | | | 1 Remove clutch pressure plate. | | | Does the clutch pressure plate have signs of wear or damage? Yes Renew clutch pressure plate. No | | B4: TEST CLUTCH DISC | | | 1 Visual check of the clutch disc. | | | Is the clutch disc worn (measured thickness < 6,5 mm), oily or does it show burn marks, are cracks visible on the friction material? Yes Renew clutch disc. No | System Test - Clutch | PINPOINT TEST C : | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | C1: CHECK BRAKE FLUID LEVEL | | | 1 Check brake fluid level. | | | Is the brake fluid level between the MAX and MIN marks on the brake fluid reservoir? Yes No Top up brake fluid, check the brake and clutch systems for leaks. | | C2: MEASURE THE PEDAL TRAVEL. | | | 1 Depress the clutch pedal by hand until it reaches the lower stop and then release it. | | | 2 Measure pedal travel. | | | Is the measured pedal travel 125 ± 3 mm? Yes No | | C3: TEST DIAPHRAGM SPRINGS | | | 1 Remove the transmission. | | | Does the clutch pressure plate or the diaphragm spring have signs of wear or damage? Yes Renew clutch pressure plate. No | System Test - Clutch | PINPOINT TEST D : | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | D1: TEST CLUTCH PEDAL | | | 1 Remove the transmission. | | | Does the clutch pressure plate or the diaphragm spring have signs of wear or damage? Yes Renew clutch pressure plate. No | System Test - Clutch | PINPOINT TEST E : | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | E1: CHECK TRANSMISSION NEUTRAL POSITION | | | 1 Ignition switch in position III. | | | 2 Start engine and run it in neutral. | | | 3 Fully depress the clutch pedal. | | | Are there any noises when the clutch pedal is depressed? Yes No | | E2: CHECK THE CLUTCH PEDAL PLAY. | | | 1 Press the clutch down manually until resistance is felt, then release it again. | | | 2 Measure pedal travel. | | | Is the play between 1 - 3 mm? Yes No | | E3: CHECK THE CLUTCH SLAVE CYLINDER AND THE CLUTCH RELEASE BEARING | | | 1 Remove transmission. | | | 2 Check clutch slave cylinder bolts. | | | 3 Check the release bearing for wear and corrosion. | | | Are the bolts loose or are there any signs of wear or corrosion? Yes Tighten the bolts and/or RENEW the clutch slave cylinder with release bearing. No | | E4: CHECK THE TORSION DAMPERS OF THE CLUTCH DISC. | | | 1 Check the torsion dampers of the clutch disc for wear. | | | Do the torsion dampers of the clutch disc show signs of wear? Yes Renew clutch disc. No | System Test - Clutch Operation | PINPOINT TEST F : | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | F1: CHECK THE CLUTCH MASTER CYLINDER. | | | 1 Check the clutch master cylinder for leaks. | | | Clutch master cylinder OK? Yes No Renew clutch master cylinder. | | F2: CHECK THE HYDRAULIC CLUTCH PIPES. | | | 1 Check the hydraulic clutch pipes for loose connections and damage. | | | Are the hydraulic clutch pipes OK? Yes Verify the customer concern. No RENEW the hydraulic clutch pipes. | | F3: TEST CLUTCH SLAVE CYLINDER | | | 1 | | | Is the clutch slave cylinder OK? Yes No RENEW the clutch slave cylinder with integrated clutch release bearing. | iB5 Manual Transmission The diagnostics are divided into groups (main concerns A, B, and C). The following procedure is recommended before carrying out any repair work or renewing the manual transmissions: Main concern A: Poor gearshifting Main concern B: Transmission noises - If transmission noises are reported, first check the transmission fluid level. If damage has been caused as a result of lack of fluid, renew the manual transmission. Find out how much fluid is left and make a note of it on the warranty charge request form.
- Check that the engine/transmission guide sleeves are present.
Main concern C: Oil leakage - Check that the leaking fluid is actually transmission fluid and not brake fluid (from the hydraulic clutch system) or engine oil.
- Check the transmission fluid level and, if necessary, drain off any excess fluid. REFER to Section 308-06 Manual Transmission/Transaxle External Controls.
- Locate the oil leak with the aid of a fluorescent test fluid and a UV leak tester.
- Clean the transmission and the adjacent areas carefully before the road test.
Main concern A: Poor gearshifting Symptom Chart | Symptom | Possible Sources | Action | | Large amount of force required to change gear | * Clutch not disengaging properly | * | | * Installation position of clutch disc | * | | * External gearshift mechanism stiff. | * | | * Internal gearshift mechanism or synchroniser assembly damaged. | * | | * Wrong transmission fluid. | * Check whether the transmission is filled with the specified fluid, if necessary fill up in accordance with specifications. | | Engaged gear jumps out while driving. | * Gear lever boot hardened | * | | * Engine/transmission mounting loose, faulty or stressed. | * Check engine/transmission mountings and renew as necessary. - | | Noises whilst changing from one gear to another. | * Clutch not disengaging properly. | * | | * Worn or damaged selector forks, synchroniser rings or gear synchronisers (usually occurs at high engine loads) | * | | Gears cannot be engaged. | * External gearshift mechanism faulty. | * | | * Mobility of internal gearshift mechanism restricted. | * Detach the shift rod from the transmission and check whether the mobility of the internal gearshift mechanism is still restricted. If necessary remove and overhaul the transmission. REFER to Section 308-03 Manual Transmission/Transaxle. | | Gearshift mechanism is stuck in gear. | * External gearshift mechanism faulty. | * | | * Internal gearshift mechanism faulty. | * Detach the shift rod from the transmission and check whether the internal gearshift mechanism is still blocked. If necessary remove and overhaul the transmission. REFER to Section 308-03 Manual Transmission/Transaxle. | Main concern B: Transmission noises Symptom Chart | Symptom | Possible Sources | Action | | Buzzing, rattling or metallic scraping noises from the transmission in idle | * Rotational vibration from the engine not sufficiently damped by the clutch. | * These noises do not affect the operation and durability of the transmission. | | Brief scratching noise during gearshifting. | * Inadequate gear synchronisation. | * Fit a complete set (synchroniser hub and synchroniser rings) and renew the two gearwheels belonging to the synchroniser unit. Because of various changes and difficulty in estimating the level of wear, complete renewal (as described above) is recommended. REFER to Section 308-03 Manual Transmission/Transaxle. | | * Faulty clutch. | * | Main concern C: Oil leakage Symptom Chart | Symptom | Possible Sources | Action | | Oil leakage | * Speedometer drive gear (leaking O-ring) | * | | * Seal lip of input shaft oil seal damaged. | * | | * Oil leaking between the transmission housing halves or from the selector mechanism mating face. | * Disassemble the transmission, clean the mating faces (check the surfaces for damage). Seal the transmission using a new housing gasket. REFER to Section 308-03 Manual Transmission/Transaxle. | | * Transmission fluid level too high or wrong type of transmission fluid used. | * | | * Check that the fluid leak is not being caused by other components (engine or power steering). | * Accurately identify the oil leak. | | * Worn or damaged components | * Take off the dust seal from the clutch housing before removing the transmission. Check the clutch slave cylinder and the transmission input shaft oil seal, as well as the front axle driveshaft oil seals and the selector shaft for oil leaks. | | * Slight oil mist coming from the transmission breather. | * Slight oil mist from the transmission breather is normal. If there are any drops on the transmission breather then clean the breather. | General concerns: Symptom Chart | Symptom | Possible Sources | Action | | Noises in the forward gears | * Transmission fluid level too low. | * | | * Engine/transmission is touching the chassis/body. | * Check the points of contact or the faulty engine/transmission mountings and renew as necessary. | | * Engine/transmission flange bolts loose. | * | | * Transmission faulty, worn or faulty components. | * | | Reverse gear cannot be selected | * Reversing light switch faulty or wrong reversing light switch fitted. | * Check the reversing light switch and renew as necessary. | | * Internal components are worn or faulty. | * | | * Internal gearshift mechanism blocked by foreign bodies. | * | | Gearshift lever not functioning - no gear can be selected | * Shift rod clamping bolt loose | * | |
