Strange clunking noise from 911

[Captaintremendous]

Gents
I have a strange noise which comes from the rear left of my 1969 911. It is an intermittent clunk which occurs on left hand cornering. Not every time but often enough to drive me nuts! It almost sounds as if something has been left rolling around in the back of the car and every now and then clunks. I have had it up on the lift, looked in the engine bay, done a spanner check on everything I can get a spanner to, but it still persists. I thought it might be cv joints, but it doesn't happen on acceleration or de celeration, only on left hand cornering. Any ideas?

[Nick Moss]

Another DDKer suffered from this a few years ago, it was the bearing moving in the hub

[jb]

It could also be wear in the big bush where the banana arm is attached

[squirejo]

Another DDKer suffered from this a few years ago, it was the bearing moving in the hub

Which can end up "ovalising" the hole, solution is machining and figment of an oversized (Porsche) bearing. All of which Neil Bainbridge can do quite cost effectively.

[Northy]

As Nick said, I had exactly this and it was the bearing moving in the hub.

[Captaintremendous]

Interesting feedback gents. Both banana arm bushes have just been replaced which has improved but not removed the problem. Bearing movement could be the next port of call. Any other starters for ten?

[Captaintremendous]

Assuming it is the bearing moving in the hub, what is the solution? Presumably a worn hub would need to be replaced along with the bearing?
Russ

[Slope330]

i m the one Nick was referring too ,it was on a 2.4 '73 model .......a new bearing solved it , plan B was a larger one off a turbo.................tried just about everything else on the way !

[Captaintremendous]

Tell me about it!!................been driving me nuts!

[Alan @ CanfordClassics]

Hi, we have had to do this a lot of times in recent years. It was known problem at Porsche as they supply an over sized bearing for the steel arm. A turbo bearing will not work it is different. These bearings are pretty expensive, our solution ends up using the original size bearing which is both cheaper and also if they require replacement in the future then then standard bearing is fitted. Every car we now restore has this machining work done to it.

HTH

Alan

[Gary71]

Is part of the fix to fit a steel ring around the hub to prevent reoccurrence? Otherwise what stops it happening again?

[Captaintremendous]

Good point. Same size bearing, same problem I would have thought. Do the oversize bearings already mentioned come in one size and require machining of the hub to suit?

[Gary71]

I imagine Alan's solution involves a sleeve between machined out hub and standard bearing. My concern is removing wall thickness from the hub which is known to be flexible maybe allows easier reoccurrence of the original problem?

[Captaintremendous]

Update. Problem now solved. It was indeed an oversize bearing that was required. The work was successfully carried out by BS Motorsport.

[dean1057]

I have the same noise coming from the left hand side.
So it number 7 on the drawing.
https://www.dropbox.com/s/6vb4q6ot4ivdb ... b.jpg?dl=0