I have a 1970 Chevelle SS396 coupe with TH400 auto and L34 350 HP motor. The car is running Eagle ST tires that are close to new. I recently had new lower balljoints installed, a front end alignment, wheel/tire rotate & balance because the car needed all of it. It was riding roughly on the hiway and the ball joints were real loose. Well, the car still rides noisily and roughly on the hiway at speeds above 60 MPH. Should I go back to the shop to complain or is there some other problem here. The rear springs are two years old, the front springs are several years old, if not originals. Any thoughts would be appreciated.

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Morris "moepoe" Porter

Aces 2674
'70 L34 Chevelle SS396

Just a thought but you might want to crawl under and take a close look at the drive shaft.Could be just shocks/ bushings but drive shafts/U-joints can be sneaky.
Harley

What do your suspension bushings look like? If they are still the original rubber ones, I'll bet they are shot. Upgrade to poly, making sure you do all of them, and the difference will amaze you!

check your bushings & tie rods, I would suggest both the upper & lower bushings are shot in both ends of the car. I had front control arm bushing that had worn out the bolt ate through the shell and into the lower control arm. After having an alignment, balljoints,etc. the car was still uneasy at speed, bushings solved the problem. Another thing maybe some looseness in the steering gear? Just a check..

jody
71ss454
ACES

I just cured this problem on my car. well part of mine was my crager ss rims. the lugnuts on those rims use a special washer that had worn outon moost of the lugnuts. the biggest problem was the wheel balencing. I had a set of tires put on less than a month ago and the balencing the tire shop was horrible. I hade a real mechanic do four on the car whell balencing and now my car holds stedy up to 140mph.. http://www.chevelles.com/forum/smile.gif
hope this helps =)

How old are your shocks?

Give your shocks a look. My guess is it is the shocks. Had this problem on a couple of cars. It was always the shocks (or 1 shock) was worn.

See if any fluid is leaking. Or pull each individual shock. Compress it by hand, see want kind of resistance it gives or if it rebounds. You will feel flat spots in a warn shock if you compress it by hand. Sometimes the shock will not extend itself either.

Shocks are not lifetime parts. You may get a lifetime warranty, but you will need to replace them if you drive your car. From my experience, shocks (aftermarket) last and average of 30,000 miles. I have heard that factory shocks last as little as 15,000. You just may not notice it.

Excellent replies, you guys have given me some stiuff to check out. I bet there are lots of people dealing with this same problem. Tough to pin down.

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Morris "moepoe" Porter

Aces 2674
'70 L34 Chevelle SS396

UPDATE: Thanks again to those of you who replied to the original post. On the way to a cruise nit etonite, the vibration became more serious and seemed to be coming from the rear of the car. Putting the TH400 in neutral while the car was rolling stopped the noise and vibes. Sounds like it's the ujoint(s) folks!!!

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Morris "moepoe" Porter

Aces 2674
'70 L34 Chevelle SS396

dont assume it is the u joint even thought they cost around 15 dollars it wouldnt be bad to replace crager rims was a problem once for me and my buddies 67 el camino had a bad vibration and we replaced tire rims u joints front bushings and then when we were down under the car we noticed the mototr mounts were bad the rubber on one side completely gone the other fell apart when we pulled the engine so we replaced both motor mounts and the tranny mount that fixed it on my bro 69 el camino ss it seemed dangerous to drive cuase the vibe was so bad and we werent sure what the problem was he had hi jackers air shocks on i dont remember how much lbs was in it but do remember alot someone told him to check it he dropped the poundage in it and it had fixed the problem but make sure you check engine mounts and tranny mounts

I almost forgot. I once developed a vibration in my 65. After looking over most of the car I found nothing visually wrong. At the same time I was considering my tranny swap, so I decided to take a few measurements while I was under the car. While measuring my TH350 I noticed I somehow lost 2 of the 3 bolts that hold on the torque converter. And the 3rd bolt was loose. Good thing I caught that one. I'm glad I got under the car right away.

** moral of the story

Don't drive your car when it's F'ed up. Fix it ASAP.

UPDATE: Thanks again to everyone who offered their advice and counsel. I just replaced rear ujoint and the car rides like a dream once again.

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Morris "moepoe" Porter

Aces 2674
'70 L34 Chevelle SS396

The perfect close to any post!!!

Man, you guys have more balls than Dick Tracey! 140 mph in a chevelle? I had a rat in my 65 and anything above 100mph was ugly. These cars are about as aerodynamic a a phone both and handle like a model A dorf.

I'm trying to cure some of that on my 67, new PST everything and 1 1/4 front sway bar with 1 inch rear, gas shocks, the whole deal.

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Wally
Gold #67
67 malibu

You are doing the right thing, Wally, in changing and upgrading your suspension. Don't get me wrong, my Chevelle feels like any other old-technology car with original bushings at high speed. But, with the bad ujoint it felt like it was gonna come apart. Anyway, I wouldn't recommend sustained high speed travel in these cars without some updating and upgrading. That said the cars should do okay at 70-80 mph provided all is in good working condition.

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Morris "moepoe" Porter

Aces 2674
'70 L34 Chevelle SS396

Just a thought, but if your car has the F41 suspension then the ride will be a lot stiffer and harsher than the standard suspension.