Clutch replacment question?

So, I have done 3 clutch jobs so far. The first was on a B13 sentra, the clutch had been done a couple years before by a shop, then the disc failed (one of the springs fell out and got stuck between the disc and flywheel so it wouldn't engage), so I took it apart, did nothing but put a new disc in and it was fine for another 50k miles until it got totaled. The second was on my Shelby Charger, the turbo oil line leaked oil into the clutch, so I bought a new clutch kit, and just cleaned up the flywheel with an abrasive pad on a drill, and it worked fine another maybe 5k miles until I sold it, and as far as I know still is working. The 3rd was my dads Legacy, since it had 330k on the original clutch, we replaced the whole clutch (it was slipping quite a bit), and since it was very worn, we had the flywheel machined at the local Napa auto parts. This one, the clutch doesn't slip, but it chatters so bad its really unpleasant to drive, and the job is probably going to have to be done over again.

Sorry for the long introduction, but my question is, I need to do the clutch in my sisters 92 jetta (almost 100k miles, clutch is slipping due to wear, not oil contamination), do I use the flywheel as is (might not be such a good idea if it has enough wear to use up a whole disc?), have it machined (how do I know I wont have to do the job over again?), or buy a new flywheel (almost triples the cost of the job)..

The clutch chatter is most likely not caused by having the flywheel machined. If the flywheel on the Jetta is not scored or showing cracking on the surface, you can clean it up and be good to go. The slipping is caused by wear on the clutch disc and or losing tension from the pressure plate.

I'd take it apart and see what the flywheel looks like. If it looks smooth, I would just use a scotch brite pad on it and reinstall.

You need to look for cracks and hotspots in the surface, but the big thing to check is the flattness of the flywheel where the disc rides. If it has worn deep enough that the new disc sits on the edge of the worn part, it should be machined.

Thats hard to describe properly. The wearinfg surface should be dead flat.

Also, have a decent machine shop cut the flywheel. VW uses a stepped flywheel, so it need to be cut on two different surfaces to maintain the proper distance between them.

As to the Subaru clutch- did you try to save money when you bought the parts? Thats a very very bad idea......

The Subaru also has a stepped flywheel, and I think it was beyond what they could do a good job on at the napa machine shop. Probably the best thing would have been to spend $900 on a ACT clutch and flywheel, but on a $1500 car that seemed like a lot. The kit I used was a Sachs one.

On the VW, if the flywheel needs machining, is it just a gamble on who you get to do it whether it works or you have to buy a new one anyway?