Sami951

Hey guys,

Going on with my mission to wrap up the recent rebuild properly, I'm now trying to figure out why my car makes a very loud and disturbing clunk / clack from the passenger side rear wheel when I'm taking off from a stop and/or applying throttle after slowing down.

It feels like there's some slack somewhere, ie. when taking off, first there's the clunk, then the car starts moving...

Clutch is new (spec stg 2), pressure plate is new, it's not the rear brake pads (they move very little and wouldn't cause a sound this loud) and it's not the e-brake (replaced the shoes and adjusted everything nice and tight).

At the moment I'm thinking CV joints. Any other suggestions?

Antonio

My experience with bad CV joints it that do not usually make a big "clack" but rather annoying ticking. It sounds like something heavy is loose. If you had the car apart for major work, make sure that everything in nice and tight back there. I would also look at the tranny mount. It tends to develop lots of play over time.

cpt_koolbeenz

Make sure your rear suspension bolts (eccentric, etc.) are all tight!

reno808

CV or how about the HUB bearing. Friends car did this, but not a 951.

tifosiman

Probably not a CV or hub bearing, they have slightly different symptoms than described.

Did you have the trans out during your rebuild? Check the transmission mount. A loose eccentric could cause this symptom as well.

dime1622

does it also do it if you dont rev match when downshifting? if so, id be along tifo's line of thought - tranny mount.

dime1622

btw, how are you liking your spec clutch? mines still a little rough and jittery when it gets going. about 300 miles on the clutch so far.

SeaCay

Does your tire have abnormal wear? Have you looked at your suspension bushings? My S2 had the same issue, turned out to be worn bushings.

Sami951

The transmission was out. Need to check the mount, I've been suspecting there's something wrong with it for quite some time (before the rebuild I was experiencing weird shaking at the rear end of the car when accelerating hard, haven't tried with the rebuilt engine yet...).

We didn't touch the eccentrics and I don't think it's the bushings either, as this problem didn't exist before the rebuild and I don't think those would go loose / wear out when the car stood for the two months it did..

Thanks for all the ideas, keep them coming

Sami951

Ok took the axle out and both CV's were in really, really bad shape, allowing the shaft to move way too much, effectively bottoming out on the wheel side.

I even had replacement CVs handy but they seemed to have ~25 splines on the inside, where as the shaft had ~35 splines - so much for the GKN guidebook which falsely states all 220hp turbos between '85.5-'88 would have the same CVs; apparently the '86 turbo uses the same joint as the N/A 944. Oh well.

reno808

"before the rebuild I was experiencing weird shaking at the rear end of the car when accelerating hard" They will do that until they snapped like me today. Lucky i was near my house. Had to walk all the home in sandles. AWSOME

tifosiman

Yep, you are right. They changed to the ones with more splines on the 87 turbo.

Glad you got it worked out, sorry it cost you more money though!

Sami951

tifo - which one uses more splines, '86 or '87? The joints I have have approx. 25 splines, the shaft that came out has 35 splines ... the car is '86 ... I'm wondering if it's physically possible to fit an incorrect shaft ('87+), and if so, could that possibly explain the rather quick failure of the joints ...

didn't cost too much btw, I got the new joints pretty cheap (a friend works at a spare parts store which sells gkn/löbro -> nice discount) and I already have somebody (with a later model 951) who wants them