Braking problems

When I come to a stop from higher (above about 30 MPH), my car shakes as if the front rotors were warped. Since it doesn't seem to happen at lower speeds, I'm starting to question the control arm bushings (or something like that). I guess my first question would be what type of bushings are on the car, and how likely is a 1996 LSi with 60K miles to have worn bushings? The rotors were replaced by the previous owner, but I'm not sure how/when/where/etc. There does not seem to be much wear on the rotors, but having seen other posts and it doesn't look like wear has much to do with anything. Does anyone have any suggestions? Thanks.

Clarke Russell

I'd say that you have warped rotors. Bushing problems would be unlikely. I had to replace mine at about 60K after a weekend run thru the White Mtns. A brake shop can easily check them for "run out" and grind them for you if there is enough meat. B.

[Beav]

I agree with Boone. Don't try to find more expensive problems, start with the obvious and cheapest first.

My car's brakes had almost imperceptible braking vibration, but when I cut them yesterday they were horribly warped - enough to create a wobbling sensation that I've been on the hunt for since I bought the car. Sometimes the wobbling would be present, sometimes not. For me that indicates either the tires are 'spotting' while resting or a problem at more than one wheel (the coming and going would then be attributed to a problem at one wheel going in and out of synch with a companion wheel's like problem.)

[Ovidiu STAN]

What's your opinion about a car oscillation when you break from 110mph? I am not speaking about break to stop just a break to slow down to 60mph.



The car is braking fine at low speed but it has this weird behaviour at high speed.

Any experiences/sollutions?

The rotors/breaks are new.

Thanks for any input.

[Beav]

More than likely the rotors have some lateral run-out. Most cars have a maximum spec of .003" per face. Consider that rotors are not exactly a space-age engineering marvel by any means. They suffer from density variations and will warp as their various densities expand and contract at different rates as they warm/cool. Add in the fact that the shippers and delivery people toss them into the back of trucks, on the shop floor, etc.

I never install new rotors without chucking them up and taking at least a light cut to make sure they're not going to cause me any grief. It's an extremely rare occasion that I find one that doesn't have some type of deformity, right out of the box. That also goes for the rotors that come in boxes stamped "No resurfacing needed".

[dromano]

what is the shoe thickness at which they need to be replaced?

[MoreIBNR]

Originally posted by dromano
what is the shoe thickness at which they need to be replaced?

Uh, zero???

[dromano]

Originally posted by MoreIBNR


Uh, zero???

Uh, I don't think so... Anyone have a Section 4 SVX Service Manual?

[MoreIBNR]

Oh, you wanted a SERIOUS answer? 1.5 mm, though I don't see why they should ever need replacement. They are only used when the parking brake is on and unless you are in the habit of driving off with the hand brake applied (I guess you like the little red light on the dash?), they should last the life of the car.

Originally posted by dromano


Uh, I don't think so... Anyone have a Section 4 SVX Service Manual?

[dromano]

Thank you