Strange Noise whilst applying brakes
Strange Noise whilst applying brakes
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nbetts

Original Poster:

1,455 posts

257 months

Thursday 12th January 2006
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Ok - I have seen these posts before as well and think that it so obvious as to what the problem is, this one however has got me stumped.

I have a 996 tt, it has done roughly 6k miles, it does not get used that often but when it does it is driven a fair distance (say 100 miles) probably once a week at the least.

When I wash the car I always dry the brakes again by driving it around for a short blast to dry them out.

When I leave the car in the garage, which is heated, I do not leave the Handbrake on.

So it came as a bit of a surprise to me when I applied the brakes yesterday when out on a bit of a blat, that they are making a strange noise. I will attempt to describe it... it is like a pulsating drum brake noise, if that makes any sense.

I have visually checked (in a manner which means I do not get too grubby) the pads and discs on all four wheels and they all look pukka and show no obvious marks.

Needless to say, the car does not have a very hard life so I will be amazed if the noise is down to wear and tear.

Anyone on here have any ideas... before I give it to the OPC.

I have also tried to be aggressive with the brakes (in an italian tune up kind of way)to see if that cured it but sadly no joy.

Rufus

5,531 posts

266 months

Thursday 12th January 2006
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try jacking up each corner in turn and spinning the wheels to see if they are biting.. might help isolate the problem corner.

nbetts

Original Poster:

1,455 posts

257 months

Thursday 12th January 2006
quotequote all
Thanks Rufus - I will do exactly that - Seems to only make the noise when I apply the brakes though. I will give it a go.

Ta

zoom_jones

858 posts

287 months

Thursday 12th January 2006
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warped discs due to high level of use from being cold?

bsgowans

84 posts

302 months

Thursday 12th January 2006
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zoom_jones said:
warped discs due to high level of use from being cold?


Definitely sounds like warped discs to me - you should be able to check by jacking and rotating each wheel in turn. If it's warped the disc will "catch" in one particlar place. Options are skimming or replacement.

JK75

318 posts

264 months

Thursday 12th January 2006
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I had the exact same sound and feel on my Boxster S.

No idea what it was but I was and thought it may have been a bit of grit between the pad and disc. Called Porsche andd they told it could be a cracked brake pad or disc ...

It did actually turn out to be a cracked brake pad....

No brainer, but was also told not to clean them when still hot as that can lead to warping with extremes of heat. Probably what I did...

Hope it helps

JK

nbetts

Original Poster:

1,455 posts

257 months

Thursday 2nd February 2006
quotequote all
Ok.

Just a quick update. Thanks for all the tips.

I spoke to my OPC and they recommended giving the car a bit of a blast to see if I can get rid of what the OPC judged (over the phone) to be a build up of corrosion on the inside of the rear discs.

I did this and applied the brakes far harder than I normally would on the public roads... it improved matters somewhat but did not completely solve the problem.

Went to OPC this lunchtime where they kindly put the car onto their ramps. Once underneath the car it was clear to see that there was a single area of corrosion on both rear brake discs on the inside (facing gearbox).

OPC advised that trying to remove by heavy braking on the road probably not that easy this time of year, as speed and grip are not as readily available due to road conditions.

I was advised that, this would wear away with time but if I found the noise too bad they would take the discs off of the rear axles and lightly skim.

£150 for the pair.

I will give it another week to see if I can wear it off, failing that OPC it is.

Where is a track day when you need one.?

legaleagleboy

605 posts

279 months

Thursday 2nd February 2006
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Whatever happens you should have the brakes bled first -- it is quite possible that some moisture/air is in an area of pipework adjacent to one side of the caliper. If so it is quite possible for this to set up a sort of vibration against the other side of the caliper.

If after bleeding and some further heavy brake applications you still have a problem, I might look at the pads themselves -- this may be a long shot but if they are Pagids I would take them out and give the faces a sand, shove them back and see what happens. (I have found the pad material on Pagids to have different density/texture)

nb if doing the bleeding yourself remember there are 2 bleed valves per corner on Porkers with Brembo calipers.

robbie_toys

14,014 posts

249 months

Thursday 2nd February 2006
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Sounds very similar to what I had on the fronts of the GT3. Didn't occur all the time, but more under medium braking. A track day the other week cleared the problem totally!

J1mmyD

1,823 posts

247 months

Thursday 2nd February 2006
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