Gavin.Grubbs

Hey All,

I drive a '92 LT1 coupe automatic. I have heard that C4s can be rattly/ loose sounding cars, especially after 20 years of driving. Whenever I drive the car, it always seems to feel as if something is loose or "off" in the suspension/tires/wheels etc. Whenever I go over a bump or rough patch in the road it is especially noticeable. I have been able to eliminate most of the interior rattles since I bought the 'Vette and greatly reduced the drivetrain noises when I replaced the rear axle U-joints and all 4 wheel bearings. I had Chevy look at it just before I replaced the U-joints just to confirm they were bad for me so I didn't drop my axle shafts for no reason and they did not diagnose anything else. Also, since that, I have jacked the car up and inspected and torqued all of the suspension and drivetrain components. Another note, the noises were there prior to me replacing the U-joints and the tires are all correctly inflated and holding pressure. The car doesn't drive or handle any differently. In short, is there something anyone knows of that traditionally goes on a 20 year old Corvette to cause this, or is it simply the nature of the vehicle?

Thanks

davewhtt

The biggest change to the better that ive made so far to reduce the rattling was #1 all new weather stripping #2 new shocks. Also after doing the weather stripping i had to snug up all the roof bolts after a few weeks. I have a 93.

bangbgC6

I agree with davewhtt's suggestions.

Without riding in your Vette it is hard to diagnose remotely as far as the thumping noise.

I hit a vicious pothole one time @ about 50; that tire held air just fine but after I rotated the tires and that Front right tire went to the back end of the car I had a thumping combined with vibration. To try to track down the issue I switched that tire back to the front the car and thumping/ vibration went away.

I ended up having to buy a new tire out right even though I had road hazard on them because the damage visible to the tire was not enough for it to be qualified as a manufacturing defect or a road hazard replacement under warranty. I suspect hitting the pothole at that speed damaged a belt in that tire. The new tire fixed the entire issue.

Other than that one of the changes that made the biggest difference on my '89 to change that disconnected feeling was when I replaced the steering rack. If you have inspected the ball joints and bushings and they are all good I am not sure where else you turn.

Good luck.

Gavin.Grubbs

Yeah,I already replaced the weather stripping and that has also helped. I have been thinking about new shocks and control arm bushings to help with the suspension. Thanks for the help!

Docderek05

I would also change the rear stablizer bar end links. in 20 years, look at the bushings they may be shot to hell, and the bushings in your rear suspension, at your leaf spring ends could really be suspect. Remember..you do not see the "goings-on" as those twenty year old rubber bits are trying to isolate sound as you go down the road, so to start..A. new fresh tires, B. new Sway Bar end links and bushings, new rubber Bushings at the Terminal ends of your transverse leaf spring, you did the Uni-joints and all the Wheel Bearings so you should be good there, the only other heavily loaded culprit could be your Upper and Lower control rod Bushings., think of the forces on them when you accelerate and brake, if the bushings are old, dry, they are bad..no question. then...on to Shocks, and their mounting points and bushings..
My big fear..on my C4..are the end bushings that are on the top of the cradle the entire rear end is hung from..I do not even know what you call them, without the manual in front of me..but it's the bushings that isolate the entire rear end in the aluminum frame above the differential. who knows what kind of noises clunk from that monster, if those go bad! Best, Derek.

DinoBob

Check your hood alignment and latch pins. Mine were a bit misadjusted and made the car sound like it was falling apart. Much better now.

ms2086

I have had the same issue for about a year now. Changed tires, brakes, rotors, weather-stripping, exhaust clamps, and rims. Checked u joints. I will be changing wheel bearings but the sound is a clanking around 40-45 mph when decelerating typically. Its been driving me nuts. I have also replaced interior and used an insulation kit. Its better but still there.

Thanks now I have a list to check over.

Mike

bugz1racing

I had this problem with my '92. It ended up being the clips that hold the brake pads in place fell off and the front of the car sounded like a lumber wagon every time I hit a bump.

Netfly

If its like the 89, the lower rear quarter, behind the rear wheel, has an interior bar bracing the body. Check for a loose nut there.

Bumpnrun

Had a noise I couldn't find in the rear of my'95.....turned out to be rear stablizer bar end links. Metal on metal...bushing was toast.

kimmer

cokeholic

Gday Gavin I too had a bang and a thump coming from the right side of my 86 convertible after rolling around all afternoon under the car I found to braces swinging in the air behind the back wheel the bolt had come out and there where banging around and not supporting the rear bar in the corner as they should have been.i was so foscuced on the rear end falling apart I didn't look around the edges hope this helps ya find ya knock

ameribrit

I have the same problem in a 1996 CE - when I go over some rough pavement, the right rear (for the most part) sounds like its going to rattle off. I believe it is the sway bar end link bushings, located just above the rear wheel, you can see it with wheel removed. I held it and it moved vertically/laterally with a slight knocking sound. I hope thats it, but wonder can these be replaced with the sway bar in place or has to be removed? I will have to replace one of the bushings in a new end link I bought from Zip Corvette (they have the end link with one of two bushings installed, you have to install the other yourself).

don hall

Fortunately, my '92 has no rattles. From my '04 SUV, a rattle occurred that was finally diagnosed as a failed catalytic converter.
Check the 'cats'.

J W Drew

Here's my .02. Had a thump in the left rear area and a squeak in the right front area. Took the Vette to a specialist and they found nothing. Took it to another specialist and he found the rear right sway bar mount loose. Thump gone, squeak remained. Back to the mechanic, replace the shocks, squeak remained. Took it back and said tighten every bolt you can find. Three hours of labor and he found the right front core support loose. Squeak gone along with $600.00. Good luck. These things are hard to find.
JW