Brake Shimmy at freeway speeds

[simplygib]

Well after all the great suggestions I got for my "running warm" problem, I thought I'd run the next issue by you guys. My '90 Corolla (4AFE 5-speed) has a serious shimmy when braking from anywhere over about 45 mph. Slower than that, there's no problem. The faster I'm going when I start to brake, the worse the shimmy.

My first guess is warped rotor(s). They've never been turned since I've had the car. There doesn't seem to be any play in the wheels when they're up off the ground, and they spin about as freely as any FWD wheel would, it seems. I've also noticed more road noise at higher speeds than it had previously. Kind of sounds similar to 4x4 truck tires rolling over the pavement, but not nearly as loud. The noise is audible even if I shift to neutral and let it coast. The slower it goes, the less the noise, until it becomes inaudible by about 30 mph.

Any ideas?

[falnfenix]

warped rotors, bad pads...depending on the age of the rotors, i'd replace them(pads should be replaced, regardless). also get your wheels balanced.

[93ToyCorolla]

Make sure the caliper pins are sliding freely. Lub them with silicon grease.

[Donald]

Noise could be cupped tires. You might have play in your front that does not show up with the wheels off the ground. I had a similar problem with my Camry and I located it quite by accident. Shop had the car up on a lift with all the wheels off the ground and couldn't find the play. The lower ball joints were worn, but would only show if one wheel was jacked up because of the sway bar.