ColinOpseth

Hey guys,
I bought a 6-speed '91 back in April. The car has a noticeable vibration that shakes the steering wheel pretty bad. I had the tires rotated in May but the problem is pretty damn scary. It's especially noticeable on roads with uneven pavement. I know these cars are little "noodley" but does your steering wheel ever shake like a wheel is horribly out of balance? It seems to come and go but it's worse on uneven pavement. I mean, it's so bad that the hood is moving around at times.

The steering is really tight. I didn't ask for the weight of the new weights they added when I had the tires rotated. The car has really sat the past six years or so. It had about 32k on it in 2005.

Ideas? I was thinking that the tires were maybe flat-spotted from sitting for so long? I think I've put 800 miles on it since April. Is it possible to test for this during a balancing test?

Thanks,
Colin

mcm95403

The tires could easily have flat spots. The shocks could also have lost their gas charge causing one (or more) wheels to "flop around" on bumpy roads. Easy enough to check out the shocks. If you get the tires nice and hot does the vibration get better, worse or no change?

ColinOpseth

It's definitely worse when the car is cold. It's been chilly (60s in the mornings) and this morning it was retarded. Easily the worst vibration I've ever had in a car (and that includes the few seconds before the left rear wheel came off my V8 Vega at 20 mph). THAT is a story, let me tell you.

What's the easiest way to diagnose a shock on these things? Just bolt it from the shock tower?

It's definitely stable at speed, though. I took it down to San Diego to the Coronado Speed Festival and it blew through a tank of gas at ~80 no sweat. Loved every minute on the freeway.

Frizlefrak

Low mile car....

Flat spotted or hard/dry rotted tires and/or shocks. Marco was the same when I bought him....felt like he was having a seizure at 62 mph. 59K miles in 2010.

Turns out 4 very hard tires, 1 bent rim, and 4 leaking shocks. Replaced tires, got new rims, 4 new Bilsteins, and he drives like a dream. High speeds, 1 finger on the wheel, doesn't budge.

ColinOpseth

Wow... I've read a lot about how stable these cars are. That's awesome. Kinda regretting not buying the ZR1 but this thing was too nice to pass on.

I'm pretty sure it's the tires. When I drive it more it seems to be better, too. I don't think it was driven 100 miles in the year before I bought it. I'll take a peek at the tires. Kinda disappointed they didn't catch the tires during the balance and rotation. I ended up buying the car with the rear rims on backward. Had them rebalanced (fronts, too) at the same time.

I guess I'll have to take a few pictures. It's a decent car.. Edelbrock heads, dyno tune, headers, aftermarket exhaust. Good enough for the few miles I drive it. My V8 Vega is the quick toy I beat on.

Klondike

Definately sounds like mostly a tire thing. They can be out of round too and you can NEVER balance that out. You can balance an egg, but you can't roll it!

ColinOpseth

Yeah, that's what I'm thinking. Thing is, these are pretty new tires. I've always wondered how long a tire has to sit with weight on it before it gets damaged like that. I had a similar problem in my '87 IROC when it sat for five years. Bumpity bump, baby.

navy_vette

New tires. Just sitting there for 6 years with hot and cold weather can do some serious damage to the tire itself. Then again, just to be safe. Put the car in the air and go thru every single bushing, rod and bolt. Feel for anything loose at all. You might be suprised by the amount of loose nuts and bolts. Get an FSM or do a search on google or something to find the torque settings for EVERYTHING.

silverja

I agree with many of the comments here on replacing the tires and shocks. You will feel a noticeable difference after replacing these items. Tires get hard and develop flat spots and shocks are not that much to replace. Your '91 is now 22 years old. No component lasts forever. When I first bought my '87 years ago, I replaced the tires and shocks. What a difference. No vibration and rode like new. Also, I went with factory spec tire sizes and AC Delco replacement shocks.

Best of luck,

John