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#1 Creaking front suspension

Posted: Mon Jun 15, 2009 10:49 am
by Heuer
Out driving with the wife over the weekend and she commented about the creaking noise when braking, especially to a stop, which has spurred me on to do something about it. It has been doing this on and off for a few years and thinking it through I reckon it is down to the anti-roll bar bushes. It happens as the nose dips coming to a stop and the only thing on the suspension that can rotate is the roll bar in its bushes I assume. The bushes are polyurethane which according to one vendor are "self-lubricating" although they then go on to list "polyurethane bush lubricant" :roll:

The creaking disappears in humid, damp or wet weather only to return as conditions improve. I did get rid of it once by spraying all the suspension bushes with silicone spray but this seems like an unsatisfactory fix for a number of reasons. My thoughts are to dump the poly bushes and go back to quality rubber types as I am becoming convinced polyurethane ones are the cause and offer no real improvement over the standard spec ones.

Any thoughts before I start?

#2

Posted: Mon Jun 15, 2009 1:01 pm
by Moeregaard
David, have a look at the links connecting the anti-roll bar to the A-arm. I've seen them "creep" on the bushes until there is light metal-to-metal contact between the link and bar. You might try removing the bushes and applying a silicone-based grease during reassembly.

You are correct that silicone sprays are not satisfactory for this. Although you are running poly bushes, if you use any of this stuff on natural rubber items the solvent-based carrier will contribute to their early demise. Don't even get me started on WD-40--I've seen that stuff misused more times than I count.

#3

Posted: Tue Jun 16, 2009 10:38 am
by Echezeaux
David,
My last 4x4 was fitted with polybushes all around, and not long after just by driving it on a normal road : couic couic!! Cric cric!! After trying several lubricants in a can, I ended up removing all bushes one by one to re lubricate them with that special grease, lasted two weeks after that I cranked up the volume of the radio ! :x

#4

Posted: Wed Jun 24, 2009 10:37 am
by Heuer
Success! The creaking under braking was down to the poly bushes on the anti-roll bar. My car has the 7/8" bar (from the S3?) and had moulded on poly bushes, presumably sold as an 'upgrade'. After removing the bar I found I could recreate the noise by twisting the bush on the bar - so much for the much lauded 'self lubricating' properties of polyurethane. I cut them off and installed standard rubber ones and also changed the link bushes whilst I was at it. Car drives, corners and performs beautifully with no untoward noises.