Please HELP! Mystery Noise

[hottrodcrazy]

Hello. I have a 1991 ZR1 and have searched and asked around everywhere that I can think of except here so far and haven't been able to either a. find any kind of solid plausible explanations or b. someone qualified and knowledgeable enough to work on a ZR1 in my area.

I purchased the car just over 2 years ago, it was a 1 owner car and to date only has just at 6,000 miles. It's been sitting almost the whole time I've owned it and clearly for most of its life. I decided to take it around the block and it's making a loud grinding noise coming from the back end, but I can't tell exactly where in the back end the noise is coming from. It sounds like brakes when they are metal on metal, but louder and it doesn't stop with the clutch or coasting. It also sounds no different in gear or out of gear.

I'm wondering if it's a wheel bearing, but if so it's just dried up from sitting for the last 20+ years since that's all it's done it's whole life basically.

If anyone can offer any help or other suggestions for a possible explanation it would be greatly appreciated. I'm located in Charlotte, NC so if anyone knows of a trustworthy qualified mechanic for a ZR1 even remotely in this area it would be greatly appreciated. I took it to the Chevrolet dealership here and was pretty much told "We can't get the parts, you need to come pick it up." yet they didn't diagnose the problem which tells me they didn't want to work on it since parts of the car were not GM made, therefore, I have no desire to even attempt taking it there again.

Thank you.

[Z51JEFF]

First off,NEVER take the car to the dealer again. If they did try to fix something you just might get it back worst that when it when in.As far as parts on the car not made by GM goes,just about everything on the car was made by someone other than GM. Sounds like maybe a brake caliper is hanging up or possibly the E brake isn't releasing.Once years ago I had a small pebble get fought between the brake backing plate and the disc,made one horrific noise. I'm sure an owner in your area can either take a look or someone will put you in touch with a reputable shop. Good look and let us know what you find.

[Dynomite]

jack the rear axle off the ground and with Trans in neutral....rotate/lift/pull each wheel and note any play or roughness. Could be wheel bearings, differential, half shafts, drive shaft, rear brakes, emergency brake.

I would start as Z51JEFF suggests

Bearings would not dry out just sitting (U-joints, wheel bearings, or anything associated with differential). Maybe something rubbing on half shafts.

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[RussMcB]

Does the noise change as the road speed increases? Does it change with RPM? Any difference when you apply brakes or turn left or right?

I like the idea of getting it up on sturdy jack stands and trying to recreate the noise. Have a buddy try to determine if the noise is coming from one side (wheel, brakes, halfshaft, ...) or a specific area (differential, driveshaft, ...)

Good luck.

[Bob Eyres]

Remember, there is nothing in that area that is ZR-1 specific. Meaning it's mostly just heavy duty C4 parts back there. The most common of all Corvette's.
I'm not from your area, but it's hard to believe there's not a Corvette shop nearby. It's in the heart of NASCAR country.
Talk to the local Corvette club, they'll know who the best mechanics are.
I know how it is to feel frustrated when you may not have the tools, or place, to start tearing it apart yourself. But whatever the cause turns out to be, do yourself a favor after it's fixed....drive the sucker. That's what it was built for.

Good Luck

[ALZR1]

It sounds like the rotors are rusted and that's what your hearing since it's been sitting most of that time that you've owned it.


AL.

[Z51JEFF]

What happens to this guy,gets the answer then disappear? Your welcome.