I've just fitted an exedy standard blue box clutch to my WRX and have noticed that in 1st or reverse it judders quite bad when the throttle is feathered. It is fine if you put a bit more throttle on, but is this normal? Thanks for your help.

It will need time to bed in... give it a few hundred miles and see how it is

Judder can be caused by ridges in the flywheel that are worn in by the old clutch plates rivits or oil contamination, did you check the flywheel for flatness before bolting the new clutch on ?

I will double check with the mechanic. He did have to change the oil seal on the flywheel. Would you feel a judder in all gears if it was the flywheel?

Generally it's only really noticeable on pull away if it's to do with flywheel surface flatness .

As sandy said it can dissappear after a while once it beds in to the flywheel surface (if the ridges weren't exessive)

I've only ever fitted 4 clutches , 1 with a new lightweight exedy flywheel and the other 3 with old oe flywheels.

I never had any judder but I had the old ones I fitted skimmed ,cos they had visual "ridges" in them .

OK thanks for the help. Will it damage the new clutch in any way?

If it's just a case of bedding into the slight ridges , once the plate face has worn into the same shape as the flywheel, it will be making full contact and hopefully not judder .

Great, thanks mate