sethlives1

I have a strange problem with my car. It is a 2005 base model coup. So no antilock brakes, or anything else special.

A while ago I had the tires rotated. 2 days later I was driving down the interstate, and the car started vibrating slightly. At first I thought I lost a weight off one the wheels or something. When I applied slight brake, it vibrated more. Then I took an off ramp, and it dissappeared. So I figured maybe it was the road.

A week or so later it happened again. Except it went from the interstate, down an off ramp, and onto another road. Maybe 2 or 3 miles. I came to a stop light, and applying brakes hard enough to make the car stop made it really come to life! It was shaking so bad I had a water bottle on the floor bouncing into the air. When the light turned green, I started off again and there was no more vibration.

I checked all 4 wheels, and they are all bolted on securely, and straight. The tires are not wearing funny at all. At all other times, the car drives smooth. No hint of a tire being out of balance.

I'm hoping someone here can help me. It has only happened those 2 times, and GM can't fix something they can't reproduce. But I don't feel safe at 65mph anymore. Could it possibly be a brake issue? What do you guys think?

Thanks.

kcb37

From what you say I would guess you need to get new rotor, (or turn them) and a new set of pads. When they start to get groves in them they can do this. Is it only when you brake? If it is under warrenty I would take it to them anyway. They can at least take the tires off and look at them. I would request to see the rotors after the tires are off, if they say it is an insurance issue tell them to take it in the parking lot and use a jack and jack stands, (what you would do if you were changing a tire) and feel and look if the rotor feel like they have groves in them, they should at least turn them and tell them to change the pads too.

sethlives1

Thanks for the reply.

It doesn't start when I apply the brakes. Though it gets much, much worse if I do apply the brakes. But only when it is shaking to begin with. Like I said, when I brought the car to a stop, the shaking stopped. The car drives smoothly, and brakes smoothly at the moment.

I have been reading though, and it seems the Cobalt has some issues with rotors. So I'll have the dealer take a look at it. I lifted it up and checked out the wheels to make sure they were on correctly, and as an after thought I peaked at the rotors. Looking through the wheel they didn't look too bad. I didn't feel them though.

It seems like if it was caused by the wheels or the rotors, I would have the problem all the time. But I don't, and I don't know what else could possibly be wrong. Unless I'm wrong about it happening all the time. It is definately a rotational type vibration. As it vibrates faster at higher speeds.

I wonder if a brake pad is not secured properly. Possibly making contact with the rotor, but when I applied brakes to stop the vehicle, it forced the pad back into it's correct position.

tlee878

i own a 2007 cobalt haven't looked to see what kind of rotors it has yet, but i had the same problem with my wifes toyota matrix after i bought it, if it sits for a period of time the new kind of rotors it has warps, per toyota service guy. you will have to replace them if thats the case. hope this helped