The most common problem is misaligning the input shaft when fitting the box. If the box is misaligned and not put in with the shaft in the same axis as the crank centreline, the clutch plate will bend a small amount, making it fail very quickly.
Also another common problem is not having alignment dowels fitted.

After the new clutch is installed & you're back on the road. Try taking it easy on the clutch for the first 150-300 miles approx. The new disc & pressure plate + remachined flywheel need some time to bed-in before lighting up the rear tires etc.
Some of the performance clutches that we install @ work have this tip in their warranty info.

ade

I do not have the knowledge to do it and also not the tools.
A very good friend of my dad has a brake and clutch place where we are going to take my car to do it on a lift.
Those car lifts are sooooo nice to work on your car with.
They do this kind of stuff everyday so I hope it will turn out better.

Now that you mention remanufactured clutch.
I think the guy who replaced my previous clutch that is chattering now is a remanufactured clutch as the old clutch that was removed was placed in the box that contained the new clutch.
It was'nt a make there was just written on the box "Genuine clutch".
I hope I have better results this time.

why not do it yourself it is not that hard, the best advise that I can give is to buy a tool to align the clutch plate, I cut of the front section of the input shaft to make my own.
Have the flywheel machined,make sure the clutch kit is new and not remanufactured,replace all seals while you have easy acces to them and above all have a few beers at hand and crank up the radio.

I think the most important thing is to get a guarantee ahead of time, something like "if it chatters within the first week, we'll do it over for free".

The only time I paid a shop to change a clutch, it ended up chattering ... and so I said I'd always do it myself after that. Athough once when I myself changed anothe cluth the same thing happened -- even though I put in new crank bushing, new disc, new pressure plate, new throwout bearing and re-surfaced the flywheel. I suspect the pressure plate had a defect.

It's very important to resurface the flywheel-I've seen guys do it with a lathe- but it's difficult to get the hard heat marks out unless you get it machined on a flywheel grinder. I agree with the cleaner the better when putting it all back together, and checking the seals too.
-Donnie

Why I also want to be there when they are replacing the clutch is to check what caused the problem.
I think it is maybe a bad presure plate or as you have mentioned a leak from my gearbox seal.
Although I have peeped into the inspection plate to see what is going on inside the bellhousing but there was no oil.
It can also be so little that it does'nt drip to leak out but be absorbed by the clutch plate.
Only taking it apart will tell the full story.
Any hints on the flywheel? It was skimmed when the previous clutch was installed.
It is also possible that they did a crappy job of it.
This is all the reasons why I want to be there when they install the new clutch kit.
I do not want a crappy job again.

The chattering can be oil from the gearbox or engine. If it happens just after installation, then it's more likely greasy fingers handling the clutch surfaces.

Hope this helps.

Basically I want to put in still the A12 clutch as the one in now is able to churp my 185 13 inch rears. There is no slipping problem.
It is just chattering like crap and it is starting to get heavy on the left foot to press.
I want it done perfectly to work for a long time in the future.
I do not want to spend money on clutches being put in like crap.
Would rather spend it on something else on the little beast.

i use a heavy duty a15 clutch, designed for vanettes, in my car, maybe you can get something similar over there as an upgrade