Clutch faults (Audi A6 C4)

Cause	Method of elimination
The clutch pedal does not return to its original position (on cars with hydraulic clutch)
Air entering the hydraulic drive, working fluid level below normal	Restore the working fluid level to normal, remove air from the hydraulic drive.
Seizure of pistons in the master or slave cylinder. Leakage of working fluid fluid in the master or slave cylinder	Replace faulty parts, remove air from the hydraulic drive.
Same (on vehicles with mechanical clutch drive)
Clutch cable jamming. Self-adjusting mechanism defective (if available)	Replace the cable.
Same (all cars)
Return spring faulty (if available)	Replace the return spring.
Clutch pedal sticking	Clean and lubricate the pedal axle. Replace if necessary bushing.
Clutch release fork sticking on clutch housing	Clean the fork pivot. Perform any necessary repairs.
Sticking or increased friction between parts in the clutch basket	Clean and lubricate sliding areas. Perform the necessary repair.
Increased clearance of the clutch release bearing on the guide in the bushing, bearing seizure	Replace the guide bushing and clutch release bearing.
Pressure plate diaphragm spring failure	Replace the pressure plate assembly.
The clutch pedal is too "hard" (on vehicles with mechanical clutch drive)
Clutch cable sticking. Cable corrosion in the sheath. The self-regulating mechanism is faulty (if available)	Replace the drive cable.
Clutch release fork sticking on clutch housing	Clean and lubricate the ball joint. Replace the bushing.
Same (all cars)
Clutch pedal sticking.	Clean and lubricate the hinge joints. Replace the bushing. Before checking, disconnect the master cylinder push rod or drive cable from the pedal
Peripheral spring jamming. Peripheral spring defect	Clean and lubricate the hinge joints. Replace the spring.
Increased elasticity of the return spring (if available). Installed incorrect return spring	Install the return spring of the correct type.
Same (all cars)
Increase in the effort required to disengage the clutch due to wear of friction linings	Inform the customer: Clutch release force increases with increasing wear.
Sticking or increased friction between parts in the clutch basket	If the distance from the rivet heads to the surface of the lining exceeds 0.1 mm, then replace the clutch driven disc.
Increased clearance of the clutch release bearing on the guide bushing, clamp under	Clean and lubricate mating parts. Worn guides replace the bushings.
Wear of the contact surfaces of the clutch release bearing and clutch release forks	Replace worn parts.
The pressure plate has the wrong springs installed	Install springs with the corresponding catalog number.
The clutch driven disk hub is jammed on the splines of the primary clutch gearbox shaft	Check for defects on the disc hub and shaft splines (scuffing). If necessary, replace the driven disk. Clean the hub splines and the splines of the primary shaft from corrosion and grease residue. Lubricate with a thin layer grease G 000 100 input shaft splines. Remove excess grease by moving driven disk along the splines of the primary shaft in both directions.
Increased noise when disengaging the clutch (on cars with mechanical clutch drive)
Transmission noise enters the passenger compartment through the clutch cable	Replace the anti-noise body parts, or strengthen them with additional noise protection.
Transmission noise enters the passenger compartment through the clutch cable (sticking, increased friction, unraveling)	Replace the drive cable.
When the clutch pedal is fully depressed, the diaphragm spring the pressure plate touches the driven clutch disc (free pedal travel less than normal adhesion)	Adjust the clutch pedal free play.
The self-regulating mechanism is faulty (if available)	Replace the drive cable.
Lubrication of the friction surfaces of the clutch pressure plate is required and diaphragm spring	Lubricate the contact surfaces with a thin layer of G 000 100 grease. Replace worn parts.
Clutch pedal sticking, pedal shaft bent	Clean and lubricate the pedal axle. Replace if necessary bushing.
Seizure of the peripheral spring axis due to increased friction, misalignment	Clean and lubricate the axle.
Increased noise from the return spring (if provided by the design)	Lubricate the spring axle.
Defective clutch release bearing or bearing race, contact surface wear (warping)	Usually fixed by replacing the bearing. Replace damaged ones guide bushings.
Defect of contact surfaces of pressure plate (bending or breakage of the edges of the petals of the diaphragm pressure spring). Violation of the centering clutch release bearing	Replace the pressure plate. Check the condition of the release bearing clutch and bearing races. Replace if necessary. Check condition centering bushings.
Crankshaft guide bearing wear (if any), misalignment engine and gearbox installations	Replace the bearing, apply grease based on molybdenum disulfide. Check the condition of the centering sleeve.
Incorrect installation of the clutch slave disc	Install the slave disk correctly.
A slave disk is installed that does not match the given type clutch	Install the disk of the required type.
Grinding noise when shifting into gear or reverse, the gear shift mechanism is jammed, gear shifting is impossible, the clutch does not work (on vehicles with hydraulic clutch)
Lowering the working fluid level. Air entering the hydraulic drive. Fluid leakage from the working or main cylinder, elasticity of the tube walls hydraulic drive. Incorrect adjustment of the clutch release fork	Check the hydraulic drive. Restore the working fluid level, bleed the hydraulic drive. Replace faulty parts. Restore the level working fluid, bleed the hydraulic drive. Adjust correctly.
Same (on vehicles with mechanical clutch drive)
Misalignment of parts	Replace faulty parts.
Pedal free play exceeds normal limits	Check the pedal free play and adjust if necessary.
The drive cable installed is not suitable for this clutch (increased length)	Install the drive cable of the required type.
Drive cable jamming	The self-regulating mechanism is faulty (if any). Replace the cable.
Same for all cars
Insufficient clutch pedal travel (carpet or covering interferes under the pedal). The clutch is not fully depressed	Notify the customer.
The grinding noise is caused only by the engagement of the reverse gear	Notify the customer. Before turning on the reverse press the clutch pedal and wait 3 - 6 seconds depending on the diameter driven disk. First, the primary shaft of the gearbox with the driven disk must stop.
Incorrect adjustment of the gear shift mechanism	Check and adjust if necessary.
The gear shift lever support needs lubrication correct fit of the gear shift mechanism parts.	Lubricate the gear shift mechanism, replace faulty ones details.
Sticking or increased friction of the driven clutch disc splines of the primary shaft. Corrosion of the driven disk hub or damage during installation. Misalignment of the driven disk hub	Check the hub splines for damage, if necessary replace the driven disk. Remove corrosion and grease residue from the hub and splines of the primary shaft. Apply a very thin layer of grease to the splines of the primary shaft grease G 000 100. Remove excess grease by moving the disc along the primary shaft in both directions. If the hub is not centered, check the position centering bushings. Check the condition of the clutch release bearing, bearing races, pressure plate and crankshaft guide bearing. Replace if necessary.
Too little pressure plate protrusion (disc installed the wrong type)	Replace the pressure plate.
Defective crankshaft guide bearing. Gearbox input shaft rotates with clutch disengaged	Check the condition of the centering bushings. If necessary replace. Check the condition of the gearbox input shaft.
Violation of mutual centering of the engine and gearbox (centering pins are missing bushings), due to which the driven disk ring is deformed	Defective crankshaft guide bearing. Before installation Gearbox install centering bushings. Check the condition of the driven disk, pressure plate and guide bearing (if any). If necessary replace.
Wear of friction linings due to gear engagement at high speeds revolutions, i.e. switching to a lower gear at high speed movements	Replace the driven disk, notify the customer.
Wear of friction linings due to intentional slippage of the clutch during acceleration	Defective synchronizers and/or shift mechanism gears. Repair the gearbox.
Incorrect installation of the pressure plate.	Deformation of the driven disk due to improper driving. Check condition of the parts. Replace if necessary. Check the position of the mounting studs. If the grinding noise does not disappear after this replacement, then check the condition splines on the driven disk hub and freedom of rotation of the primary shaft Gearbox, check the condition of the guide bearing (if any) crankshaft, repair the gearbox.
Same for all cars
The grinding noise occurs in 2nd gear and only when the transmission is cold	Notify the customer. Change if necessary oil in the gearbox, filling in oil with a higher viscosity.
Increased thickness of the driven disk	Replace the slave disk.
Sticking of the driven disk to the flywheel due to corrosion (car not used for a long time, high relative humidity)	Lightly clean adjacent surfaces. In case of severe corrosion replace parts.
The clutch is slipping (cars with hydraulic clutch)
The piston of the master or slave cylinder does not return to its original position position	Replace the master or slave cylinder. Change the working fluid, bleed the hydraulic drive.
Same (vehicles with mechanical clutch drive)
Incorrect adjustment of the drive cable (insufficient free play cable stroke)	Adjust the cable. If necessary, replace the cable with the desired one type.
The self-regulating mechanism is faulty (if available)	Replace the cable if necessary.
Cable jamming	Replace the cable if necessary.
Same (all cars)
The driven and pressure plates are of the wrong type	Replace with disks of the required type.
Wear of the driven disk, burnout of the pressure plate, formation grooves due to overheating, deformation of the pressure plate due to improper installation, weak pressure plate force. Incorrect driving under normal wear and tear	Replace the driven and pressure plates. Notify customer.
Increased friction of transmission parts, sticking of pedal rod	Clean and lubricate the hinge joints if necessary repair.
Oiling of clutch discs and flywheel. Wear of crankshaft seal. Grease getting onto the rubbing surfaces due to excessive lubrication of the hub slave disk	Replace the driven disk. Clean the contact surfaces of the pressure plate disk and flywheel. Replace the crankshaft seal, remove excess grease from the primary shaft.
Incorrect installation of the slave disk	Install the disk correctly. Check the condition of the slave disk. Replace if necessary.
The clutch "leads", jerks when starting to move (cars with hydraulic clutch)
Incorrect clutch adjustment	Adjust correctly.
Air entering the hydraulic drive, defects in the main and working cylinders	Replace faulty parts. Check the working fluid level, bleed the hydraulic drive, check for leaks.
The master or slave cylinder pushrod does not return to starting position	Replace faulty parts. If necessary, replace the working one liquid. Bleed the hydraulic drive.
Same (vehicles with mechanical clutch drive)
Cable jamming	Replace the cable.
Pedal sticking.	Before checking, disconnect the cable from the pedal. Clean and if necessary, lubricate the hinge joints. Replace the bushing if necessary.
Clutch release fork sticking or excessive friction	Clean and lubricate the hinge joints. If necessary replace the bushing.
Same (all cars)
Unstable engine operation	Check engine adjustment, eliminate the cause.
Driving errors: too low revs when accelerating	Notify the client.
The slave disk is of the wrong type	Replace the disk.
Noises at idle
Damping springs broken	Replace the slave disk.
There is no damping plate on the driven disk (increased noise on idle)	Install the damping plate.
Deformation, breakage or ovality of the pressure plate	Replace the pressure plate.
Unstable engine operation	Check engine settings, eliminate the cause.
Violation of the correct position of the engine due to softness of its suspension parts	Check engine mount components. Replace if necessary.
The shock absorbers are faulty	Replace shock absorbers.
Oiling of the friction linings of the driven disk, contact surfaces pressure plate and flywheel	Determine the cause of the oil leak. Repair if necessary. Replace the driven disk. Clean the pressure plate and flywheel.
Increased clearance of the clutch release bearing on the guide sleeve (uneven distribution of force acting on the diaphragm spring pressure plate)	Replace the bearing and guide bushing. Check the condition of the parts and articulated joints.
Uneven operation of the pressure diaphragm spring due to increased play in the clutch release bearing causing uneven distribution diaphragm contour forces	Check the mating surface of the friction linings of the driven disk bearing surface of the flywheel and the condition of the diaphragm spring. If necessary replace the pressure plate. Replace the bearing and guide bushing.
Deformation of the clutch basket during assembly, resulting in damage correct position of the pressure plate	Clean the flywheel and pressure plate from grease. If serious damage is found, destruction (burrs, traces of overheating, grooves) replace. Remove grease from the hub and from the splines of the input shaft. Apply a thin layer of G000 grease 100 on the splines of the primary shaft. Remove excess grease by moving the driven disk along the primary shaft in both directions.