Thread: Brake Wobble.
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      10-24-2012, 04:10 PM   #28
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United Kingdom

Drives: 325d MS Touring
Join Date: May 2010
Location: Peterborough

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Originally Posted by bigandy View Post
Braking from motorway speeds to a standstill wouldn't put in anywhere near enough temperature to cause pad transfer, you're talking about needing 600C plus before that kind of thing happens.

All discs have a level of DTV and judder as new, this will deteriorate over time through temperature cycling or in some cases pad transfer. This is normal though and should only be noticeable to the driver in extreme cases.

The reason a driver can feel it is usually because a small amount of run-out or DTV has built up and old or worn out bushes are no longer capable of isolating the vibration from the driver. Replacing the bushes will fix it unless the run-out/DTV is really bad, changing the discs will fix it temporarily, until that small amount of runout/DTV has built up again. The usual culprit is the FLCA rear bush, (or the equivalent depending on suspension architecture).

'Re-bedding' the brakes as BMMiniparts mentioned will temporarily reduce the DTV, but it will eventually come back.
Strange this. I have had my car for 5 months, done 10k miles and never had a brake wobble issue.

It is all about understanding why brake wobble evolves. Automatics are more prone because of the nature of sitting on the brakes when at traffic lights, junctions etc.

Never brake heavily to a standstill and sit on the brakes, let the car roll half a turn and use the handbrake.

Avoid long braking stops, where the pads are incontact with the disc.

Every now and again brake hard to deglaze the discs to remove the pad transfer.

Alternatively lift of the accelerator sooner so the car weight slows it down - thus saving fuel. Then brake but with more power thus not sitting on the brakes for too long.

In addition you should never need to brake when on any dual carriageway or motorway, except for roundabouts or slips roads thus reducing the pads transfer risk. I know of people who have got 80k miles from a set of discs.

It is all down to driving styles, not the actual parts, just how they are used.

E30 M3 1987
E34 M5 1990
E91 325d - 'Ecotuned'