Questions on suspension issues.

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Questions on suspension issues.

Post by Hs1973 on Sun May 13, 2018 9:16 am

Hi guys. I have always gotten usable answers trough this forum, so ill try again and see what you guys Think of this.

I have a 75 chevelle thats totally restored over a periode of 5 years. Every part of the chassie is new or rebuild. I have new rubber bushings in all control arms new 1" lowering springs and gas shocks. New american racing rims with bf Goodrich tires, new brakes and so on. From the first time i Got it on the Road it worked great and the ride was Nice, but it has always had 2 issues i have been trying to get rid of. The first is that from time to time there would be a clunk from the front suspension, usually when backing out and braking would make it clunk just as the suspension would lift and the car would stand still. No clonking going over bumps etc.

The second thing was a oscillating vibration when getting close to 60 mph and over. It felt like it was coming from the back and i would feel it in the seat, not the steering wheel. It would get worse going faster and disappear below 60mph. I have a new driveshaft and other stuff changed out, it would still be there.
Now here is the thing. I realised that the clunking sound was from the front control arm bushings not Being tight in the arms, wich from time to time made the arm rotate on the bushing shell causing a clunk noise. I have fixed the problem and went out on a test drive. To my surprice the vibration i had is almost gone and does not appear before 75-80 and not near as much as it used to be. I stil need to fix the lower arms as the clunk is still there but not as pronounced as before. So im guessing all the bushings have the same issue. Also the steering feels alot tighter than before when i Think about it.

Am i crazy thinking the 2 things have been related all along or is it just wishful thinking. My tireman told me that the rear tires 275-60 15 bf Goodrich was a little out of round, so he did what he could to balance the rims and tires as best he could. I always thought i would eventually need new rear tires to get rid of the vibration issue. But now im not sure what is going on. Im hoping to get rid of the last vibration when i fix the rest of the bushings. Im changing them out myself this time, seeing that the last time the shop did not tell me about the bushings Being to easy to Press in.

Any and all opinions on this is welcome as im not sure on what is going on with this . Kind regards from Copenhagen.
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Re: Questions on suspension issues.

Post by Joe73 on Sun May 13, 2018 12:13 pm

Maybe switch the front tires to the rear and see if the vibration changes. Or borrow some tires and try them on the front AND rear of your car to try to isolate the problem.

The control arm bushings are obviously press fit. The would only need to walk out of their seated position about 1/4" to 3/8" to become loose. Thats not good. If they are snug when fully seated maybe a quick dot of weld from a MIG to tack the bushing to the arm? Might stop the problem. Otherwise you might need new arms.
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Re: Questions on suspension issues.

Post by bigredlaguna on Sun May 13, 2018 3:06 pm

Are the tires actually out of round, or just imbalanced? I suggest fixing the rest of the bushings first because you largely erased the issue with what you have done already.
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Re: Questions on suspension issues.

Post by Hs1973 on Mon May 14, 2018 2:47 pm

I had the bushings replaced when i restored the car. They fit tight and sit right all the Way in, they are just not tight enough to withstand the arm from a little bit rotation on the outer shell when the suspension is Being forced into its outer positions, which in turn cause a clunk when the arm jumps on the shell. I have given them a couple of small tack welds wich seem make it ok.

I had a really talented tire man balance my tires. He did use alot of time finding the low spot on the rim and matching the position of the tire accordingly so they would be as good as could be. I have not had a Big issue driving it around like it was. I had almost gotten used to the Way it would vibrate a little going fast. I was just amazed that fixing the bushings seemed to make the vibration almost disappear.

I had plans to try a pair of wheels from a buddy since i have different size front to back, just to see if it would go away. If it did i was prepared to buy new tires for the rear. I am comitted to find the last little annoying rattles and other little things including the vibration. And i will eventually fix it all. I was just curious to know if i was just imagening things when it seemed that the vibration was less after the bushing problem was solved.

I have usually driven the car during summertime and fixing the little things during winter where its stored away. But this means i have to wait until summer to see if things are fixed. And the things i have tried so far has made the vibration better but not dissappear. Im hoping that other tires will make the last go away. So far it has been a sum of a lot of little issues, like driveshaft Being to short, a bad shock, bad balancing of tires, a Bent aksel in the rearend and now the bushings. Every fixed item has made it better every time. Just need the last 5 procent to make it perfect. I need money and time though and i have none of both.
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