Hey guys. The brakes on my '89 LE have a vibration, but only about 1/2 of the time. It goes from being perfectly smooth sometimes, to being downright violent other times. The harder i get on the brakes, the worse it gets.

I am guessing that it'* the front brakes, since I just did the rears a few months ago. What I don't get is why the vibration wouldn't be constant. Why does it come and go as it pleases? Weather seems to make no difference.

I'm confused. :?

Sounds like warped rotors..the hotter they get...the more warped they get..especially during hard braking

Is that so? I thought that a warped rotor was just warped - always. I guess it does do it worse when it'* been driven. Although today it did it after nothing but miles of highway. Do you suppose that wheel bearing heat could affect it?

Assuming that it'* the rotor, as suggested, should it be turned or replaced? And if it is turned or replaced, must the pads be replaced? And if the rotor and/or pads are turned or replaced, must both sides be done? I've never done disc brake work, only drum. Any advise or estimation of cost would be welcome.

thanks for the input.

If its not a warped rotor i would check the caliper bolts for either being loose or stripped. i had the exact same symptom after a 1200.00 brake job from Midas Muffler about a year and a half ago. It only did that AFTER the brake job. I took it back 4 times, each time they said the rotor must be warped and turned it. IT never helped and i didnt wnat my brand new rotor being ground down to nothing so i stopped going. ALso because if i went back in there again i would have killled somebody. THEN, i got new rotors and pads and did them myself. (check my Sig) Taking my left front caliper off i noticed that it took no pressure at all to remove one of the bolts. when i got everything back on, tightening that same bolt and guess what? it just kept turning and turning. the seat on the caliper was stripped. i got everything back on, took it to the dealership the next day, and they helicored the seat, and gave me a new caliper bolt. My brakes have never been smoother or better since ive owned the car for 5 1/2 years! It wasnt that expensive either and its something you can check yourself rather easily.

Since the Bonne has a floating front rotor it is critical to clean the surfaces before mounting. Just a little piece of crud wedged and it will vibrate. Is also important to torque the wheel nuts in stages and staggered to 90-100 lb-ft. Mis torqued wheel can also cause vibration in rotor.

I'll be checking the rotors.

Can they just be turned, or do they need to be replaced?

Do I need to do both sides?

Must I replace the pads at the same time?

Thanks again.

That'll do, thanks.

Nice to see you back online Jon

Thanks man, I'd wondered if anyone had missed me, or figgured i'd died trying to set the record top speed for an '87-'91, or something.

In reality, life has just been busy, and bonnie hasn't been acting up too much lately. It'* good to be back though.

Glad to see that RLD is still running well for you, btw.