Clutch Repair

Master and Slave Cylinder

Symptoms: clutch pedal won’t return all the way to rest position, encouragement from your toe may bring it up.
Each cylinder new is about $60-70, there are rebuild kits available, and sometimes just changing the brake fluid will bring them back to life.
Replacement Clutch Kit
A Sachs kit will be substantially less expensive than OEM Audi.
Things to replace:
  • Slave cylinder
  • Clutch master cylinder
  • Throwout bearing
  • Throwout bearing sleeve (metal, not plastic)
  • Pilot bearing
  • Output shaft seal
  • Driveshaft seals (3)
  • Turn flywheel
  • Rear main seal (optional)
  • Oxygen sensor (optional)
Things to check while you’re in there:
  • CV joints and boots
  • Starter
  • Transmission wing to subframe bushings
  • Any hoses (or other stuff) that are easier to access now that the tranny is out
Double-Clutching
Audi manual gearboxes are quite strong, and along with the clutch, will last a long time. However, some have reported worn out synchros on high mileage cars, probably due to years of abuse (by the previous owner, right?). The synchros allow smooth shifts because they match the speed of the gearbox to the engine automatically. When they go out, you’ll get grinding noises when selecting a certain gear and it’ll be difficult or impossible to move the shifter into that gear, especially during a downshift. Even though it’s a gearbox problem, not a clutch problem, if you are unable to select a gear because of a bad synchro, you can use a technique called double-clutching to get by until you can fix the gearbox.
3rd to 2nd downshift example:
  • press clutch
  • from 3rd gear, select neutral
  • release clutch
  • blip throttle – the amount of throttle input will vary depending on your speed
  • press clutch
  • select 2nd gear
  • release clutch
What’s happening is while you blip the throttle in neutral with the clutch engaged, the input shaft of the gearbox is brought up to the same speed of the gear you want to select (2nd) thus matching the speed and producing a smooth downshift without slowing the car down significantly. Doing this while upshifting is even easier, you just remove step #4, but you have to do step 3 when the engine falls to the rpm that corresponds to your road speed in the next higher gear. It’s not usually necessary for upshifting, because the input shaft naturally slows down when you press the clutch anyway, so it’s close to the proper speed of the next higher gear.
This all happens in less than 1 second. If you hesitate too long, the input shaft will slow down, defeating the previous action. It takes practice to get the hang of it, but once you do there’s something satisfying about coordinating all this action in such a short period.