medblueC4

I have a 1991 ZR-1. Lately I've noticed a grinding/ squealing coming from the left rear wheel. I used to only notice it if I was drive next to a concrete wall or barrier, but now its all the time, all speeds. I notice a vibration in the car at highway speeds too. I just did brakes at all four corners hoping that would fix it and it didn't. Wheel bearing or u joints?
Matt

mhobtr

You shouldn't be driving it until that is corrected. Failure of either a bearing or U-joint can be devastating.

ccmano

Wheel bearing issues are common on all C4's. I would start there. Raise that corner of the car in the air and check the wheel for looseness. Grab the wheel at the top and bottom, firmly try to wiggle it top to bottom. There should be no looseness. As noted also check the u joints on the half shaft although bad u joints generally exhibit a clicking sound first. The final possibility is the brake caliper if the piston is frozen and the pads are dragging.
H

combatdoc

The wheel bearing or spindle needs changed, I have done both on my car and afew others with the same symptoms. It is not a hard job at all.

combatdoc

The wheel bearing needs changed, I have done both on my car and afew others with the same symptoms. It is not a hard job at all.

medblueC4

I changed the wheel bearing and it still squeaks. Ugh. I greased the splines and the teflon washer but didn't know I should change the washer until now. There is no play in the u joints and no clicking. Just a squeak/ squeal.

ccmano

There are only a limited number of possibilities. I assume you checked the brakes, the caliper is not frozen or pads low? The washer could be a possibility. Other than changing out the u-joint there nothing else there.
H

medblueC4

​​​​​Yes pads are new calipers are good.

mhobtr

I've had good luck finding bad u-joints on C2's and 3's by driving around the block a few times and then crawling under the car to the feel each joint. The bad one will be considerably hotter than the others.

I've never tried it on my 91 ZR1 so I'm not sure if you can get to all of them without burning your arm on the exhaust.

ZR WON

I wouldn't have believed this unless I was there....

Many years ago, back when the ZR-1 Gathering was 'the place to be' in May (late 90s, early 2000s), Hal H's Monster LPE 415 was having a squealing / squeaking sound originating from the passenger rear wheel area. Everyone thought wheel bearing. We changed it in the driveway of Dr. T's home. Let it down off the jacks, pushed it up and down the driveway, still made the noise... I got out a broomstick and tried to isolate the sound while others pushed (that was a funny scene in and of itself). I grabbed some WD40, sprayed it on the rubber bushing ends of the two trailing links. Voila! Squeal gone. And Hal ran 11.2@135 later that night on street tires... Those were the days....

Brian A.
90 ZR-1
12.09@118
01 Z06
not quite stock