vibrations - BMW Forum

Rich328 · 09-02-2004, 05:36 AM

I've got this problem which i keep asing for answers on...... so can anyone help me

the problem is.

when im braking in my car, the steering wheel vibrates......... and also when your coming to a stop in the car you can feel the brakes as if its oval? not completly flat is what im trying to say - its as if the brake discs have some unequal parts on them.

any ideas?

BMWBeauty416 · 09-02-2004, 08:19 AM

go have your brake disks turned new pads and an alignment that might/should fix it and tell me how it goes

~*Teg*~

Rich328 · 09-02-2004, 09:02 AM

do you think its just the front discs mate? or could it be the back ones?

xsperf · 09-02-2004, 10:36 AM

yes dude, ur rotors, or brake discs are warped, if a some are warped, just replace all of them, and ur pads too, unless u did that recently

nycbmw325is · 09-02-2004, 10:59 AM

Quote:

Originally posted by BMWbeauty416@Sep 2 2004, 08:59 AM
go have your brake disks turned new pads and an alignment that might/should fix it and tell me how it goes
~*Teg*~

While i would turn rotors on my own personal car.. Doesn't BMW advise against turning rotors? I know a lot of other forums also say to replace them becuase THER BMW rotors are very prone to warping under the best of conditions and turning only exacerbates the problem.

Bear · 09-02-2004, 11:20 AM

Rotors (discs) first, and maybe they can be turned and maybe not. Next the control arm bushings and ball joints.

wulley1 · 09-02-2004, 04:29 PM

Since I am in the process of replacing my braking system, I'll give you this advice. It is usually financially smarter to replace the factory OEM rotors than to "turn" them. "Turning" usually costs about $20-$30 per rotor. I priced out factory replacements to be $40 (each) for the front and $30 for the back.

Since it's only about $10 more to buy new ones, you might as well replace them. A new rotor will last a lot longer than a turned rotor.

Rich328 · 09-02-2004, 04:47 PM

As seen as you've all be v.helpful maybe you can solve my next problem i have.

The car seems to have a rattle underneath it - firstly i thought it was the catalytic convertor - so i had it spot welded. But the rattle is still there - its nothing to do with the cat...

any ideas?

wulley1 · 09-02-2004, 07:10 PM

It seems like a lot of people complain about a rattle from underneath their cars. I have one that comes from the rear and can't figure out what it is either.

bitcore · 09-02-2004, 07:44 PM

Get new ones. It's silly to re-machine the rotors and grind down the disc when you can just get some fresh ones and be good for another 150,000+ miles. Rotors wear out too, not just pads. So, it'd be like milling off a couple milimeters of your brake pads to eaven them out, just get some new ones.

Warpage is usually caused when a hot rotor gets uneavenly splashed with cool water, EX: from a carwash. Sometimes it's caused by extreme driving conditions, which I have yet to hit

The rattle could be caused by a loose heat shield. I have the rattle in the middle of the car, at low RPMS, it resonates and rattles like a bitch. I havn't visually confirmed it yet, but that could be your cause, and the welder may not have noticed.

97alpineM3 · 09-02-2004, 08:00 PM

Yes... warped rotors are caused by extrem changes in temperature...

I had this happen to me on one of my favorite back roads about a year ago... I was giving her all she had on a small straight away... and was quickly coming to a rather sharp left turn.. depressed the brakes... felt the result.. and started to release the brakes.. and my left front brake locked up on me.. for about 10 feet... scared the shit out of me.. but thank god it still let me push the car to the left a little before it let up.

BMW's rotors are made so that the brand new part will have a certain time interval untill they are out of specs. Durring that time.. the composition of the material is made in such a way that it is very unlikely to warp or break apart. When they get out of specifications they are more prone to warp and break due the less material to absorb temperature changes. Simple actually. Dont mill them down or you will be even more prone to warpage and the such.

Get new ones.

les

bitcore · 09-02-2004, 08:10 PM

In other words, thinner metals are more prone to warp than thicker metals.

theogill · 09-02-2004, 08:39 PM

i'll also be getting new rotors/pads soon--same issue.

Also, re: rattle. mine had the heat shield removed already, but a nasty loud rattle coming from one of the weld points. my local mechanic stuck a hose clamp around the loose spot weld and voila, noise gone. simple, yet genius. hope you have an issue thgat can thus fixed

ted