vibration issue, brakes?

[yellow2k]

Only when the car is very cold and has been sitting for a long time (overnight like) , I get a vibration that I can feel in the seat of my pants, and through the steering wheel. The frequency increases with speed. After the first complete stop from moderate speed (45mph+) the vibration is gone.

My guess is that one of the brake pads is partially on the rotor and recedes after the brakes have been warmed up and actuated a few times.

Any suggestions as to what else it might be? Is it a real problem or nothing to worry about?

Thanks ya'll.

[karlooz]

could be your tires have flat spotted. the kumhos that i had on my boxster did the same thing.

[yellow2k]

How do you flat spot tires in a car with antilock brakes? :huh:

I doubt that is it since it goes away after thr first hard braking.

[nova996]

Flatspotting is from the car sitting on one spot of the tires and flattening that part out. If I don't drive the car for a few days, I get a little vibration also which goes away once the tires are warmed up.

[yellow2k]

Ahhh. in my line of work, we call tires that have large flat areas on them due to improper use of the brakes. Like where the wheels locked up in braking at high speed. Lots of white smoke, and all... flat spots on the tires. Anyhow, this happens just as the car has sat overnight... usually when its below freezing outside, probably close to it in my garage. I checked tire pressure the other day and it was right on. (about 30-32 psi warm on Contis)

[karlooz]

i suppose i should have used another term other than "flat spotting" but i couldn't find any other. i too have found that the colder it was the worse the condition.

Edited February 4, 2004 by karlooz

[SFBayArea Jimmy]

yellow2k, "tire pressure about 30-32 psi warm on Contis." ??

I think your tire pressure is too low and that would make the flat-spot a lot bigger and the vibration as a result, a lot stronger.

From the manual, Tire Pressure for 17" is 36/36 cold. & 18" is 36/44 cold.

[yellow2k]

Yea, that could be a problem. I'll check the manual and make that right. Thanks for the heads up, SF.

Patrick