Shebs

Hi all,
I have been suffering from vibration while braking from high speeds (around 130 km/h) since I bought my car. BMW replaced the brake discs three times under warranty at 3000 km, 12,000 km, and 23,000 km. The third time, which was one week ago, they changed the bushings of the front struts (that was their description) in hope of them being the reason .

I lost hope in the service engineers here :thumbsdown: , no one knows the reason behind the consequent failure of discs because today I started feeling vibration again (after only 1000 kms). They tried to point at my driving style, but I reacted so furiously that they had to retreat .

Has anyone heard of such a problem, and if so, what is its remedy?

needforspeed

No vibration from brakes in my car at all....got to be something wrong with yours.

Comments on your driving style are a bit much ..... I though this was supposed to me the ultimate driving machine... not something that you can damage by braking hard .... :thumbsdown:

Shebs

Exactly, I don't understand how did they even have the guts to mention my driving style . I really responeded very aggressively to the engineer who mentioned my driving style .

I don't know why is my car so different than every other 5-sereis in the world . I added 7 litres of Mobil-1 since I bought it (24,000 km), and I replaced three sets of front brake discs. I guess that is pretty unusual .

JWBMW

You mentioned (on another thread) brake pad wear. Perhaps the discs are suffering from thermal shock under heavy braking due to the cast iron carbon content being incorrect for a performance vehicle. The discs do have a low wear rate for a performance car suggesting that they might be more liable to thermal shock. Was there any sign of cracking developing on the discs?

Shebs

Hi JWBMW,
I was told by the service engineer that the discs did not show any blueish color, that means that they did not suffer thermal shocks (that is what he said, it is not my opinion). And if it was from thermal stresses, then why am I the only one suffering from that? Also the brake pads mentioned in the other thread were the rear ones not the front (the rear were changed at 22,000 km, the front will be gone by 30,000 km max).

Could it be defective brake pads? Being a mechanical engineer, I know that it is impossible that the pads can affect the discs because of the discs being much harder, but it is always good to ask .

JWBMW

Could it be defective brake pads? Being a mechanical engineer, I know that it is impossible that the pads can affect the discs because of the discs being much harder, but it is always good to ask .
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Wouldn't have though it likely with the pads as the manufacturing tolerances on the compunds would very tight. Also unlikely to warp the discs without a heat issue. Perhaps your service agent is making a wrong diagnosis and you should get them to refer it to BMW

pedrollo

With old cars you would look to a sticking caliper after recurrent disc problems.

I have a vague recollection that the 5 has a system which takes up the travel in the brakepads in anticipation of braking - I would certainly be looking hard at the brake system itself.

If the pads are wearing abnormally then even more so.

VTbound

Who is tightening wheel bolts? incorrect torque could cause this.

ImolaRedM

That's my first thought too. Check to make sure the wheels are torqued right. If not you could end up with warped rotors very quick.

Shebs

BMW Egypt are tightning the bolts . I guess they should be able at least to get that right!