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On my 1981, I’ve been slowly working on handling and suspension.
It’s a weekend drive, not a racer, and don’t want anything crazy, just want to make feel right.
So far, I’ve:
· Replaced all the front and back bushings with polyurethane.
· Replaced the rear monospring with composite 330 pound unit.
· New BF Goodridge tires.
· Tighten and inspected everything.
· Rag joint and other components are tight and seem in good shape.
· Bilstein’s are about 10 years old but maybe 5,000 miles on them.
· Had a 4-wheel alignment done.
It’s gotten better but car doesn’t ever feel solid. At highway speeds it floats and is twitchy.
Today driving at 70 I realized while the steering wheel has nearly no play it’s constantly needing adjustment down the road to keep it straight. I’m working hard to keep it right.
Then I realized it’s not the front that floating but the rear of the car.
The back of the car floats around and I’m constantly adjusting the front to keep it straight.
When I hit a dip, suddenly I’m trying to keep the car in line and chasing the back of the car.
Nothing in the back is loose and I’ve relaced just about everything but the Swing Arms.
The Swing Arms are original and are on my list but want to see if they could be the cause or something else before I jump into that big job.
When the fronts don't have enough toe they tend to 'hunt' down the road; I wonder if lack of toe in the back allows the rear to hunt also, or sway. And, you should check your trailing arm bushings to see if they are shot and to make sure your arms are shimmed tight. Good luck on your endeavor..
I just installed new Trailing Arms and bushings and had a alignment on all 4 corners. The Swing Arms bushings aren't in great shape but not too bad but the only thing I haven't changed. Wouldn't think that would cause this problem. Going to take the wheels off tomorrow and take another good look there. Also, going to check the rear spindles for play. Maybe the bearings are really bad.
My 79 was much improved by adding a Borgeson box, a new idler arm, and a tiny amount of front toe-in. My 80 needed everything, but especially trailing arm and strut rod bushings.
Lots of caster in front gets rid of the floatyness, new rear bushings (and heim joints on the strut rods) get rid of the spooky handling.
I just installed new Trailing Arms and bushings and had a alignment on all 4 corners. The Swing Arms bushings aren't in great shape but not too bad but the only thing I haven't changed. Wouldn't think that would cause this problem. Going to take the wheels off tomorrow and take another good look there. Also, going to check the rear spindles for play. Maybe the bearings are really bad.
I'm not sure what you are calling "swing arms". At first I thought you were talking about the trailing arms in your OP but then you stated the above.
I would keep an eye on the rear trailing arm bushings. You said you replaced them with poly. I used poly on my 66 and 68 trailing arms. I had to replace sets on both cars because they both crumbled and pieces fell out. Four of my friends experienced the same problem. Some people swear by them, some swear at them. If the rear feels like it want so steer the car, the trailing arm bushings or shims may be suspect. Jerry
Sorry if I wasn't clear, I replaced the rear Strut Rods, all 4 shocks and had it all aligned afterwards.
This morning, I lifted the rear of the car and see if there was any play on the rear tires. I checked at 12 and 6 and at 3 and 9 and found no back an forth.
I pulled off the rear tires and everything is tight and nothing looks warn. The only thing I haven't changed are the trailing arms. I took a few pic's and while warn they look ok, I think. Don't see any movement there but that may be because I can only apply so much force manually.
I got a pair of rear tires once and subsequently my car got really twitchy..... not right away either so I didn't put it together until I had to change a tire for some reason ( don't remember why???). Anyway, I would have never expected the rears to have done that....
so, if your tires are the same size you can try moving them to the front to see how it feels.
Originally Posted by TO_Vette
On my 1981, I’ve been slowly working on handling and suspension.
It’s a weekend drive, not a racer, and don’t want anything crazy, just want to make feel right.
So far, I’ve:
· Replaced all the front and back bushings with polyurethane.
· Replaced the rear monospring with composite 330 pound unit.
· New BF Goodridge tires.
· Tighten and inspected everything.
· Rag joint and other components are tight and seem in good shape.
· Bilstein’s are about 10 years old but maybe 5,000 miles on them.
· Had a 4-wheel alignment done.
It’s gotten better but car doesn’t ever feel solid. At highway speeds it floats and is twitchy.
Today driving at 70 I realized while the steering wheel has nearly no play it’s constantly needing adjustment down the road to keep it straight. I’m working hard to keep it right.
Then I realized it’s not the front that floating but the rear of the car.
The back of the car floats around and I’m constantly adjusting the front to keep it straight.
When I hit a dip, suddenly I’m trying to keep the car in line and chasing the back of the car.
Nothing in the back is loose and I’ve relaced just about everything but the Swing Arms.
The Swing Arms are original and are on my list but want to see if they could be the cause or something else before I jump into that big job.
Stick a big screwdriver in the trailing arm mount pocket and attempt to pry the arm one way and then the other. If it moves, try to determine if the issue is the bushing or missing shims. Then do the other side. There is a high probability that the bushings are shot and you will see one or both arms move independent of the bushing.
Looks like bad trailing arm bushings to me. That bushings or the bearings are about all you haven't changed that could cause spooky handling. Test them as mentioned first before you decide to fix them.
Pulling them is a pretty big job. But rebuilding them is even bigger and requires specialized tools and knowledge. I'd suggest rebuilt ones from Van Steel, Zip or Bairs, or others.
Last edited by leigh1322; Jul 8, 2021 at 07:47 PM.
post your alignment sheet.. no one has been in those rear shims.. no adjustment was made..
are the bushings shot? maybe.. but maybe not.. suggested as mentioned try to move them and see..
i would start with 4 wheel alignment, they probably wont have rear shims.. so you may need to buy...
I got a pair of rear tires once and subsequently my car got really twitchy..... not right away either so I didn't put it together until I had to change a tire for some reason ( don't remember why???). Anyway, I would have never expected the rears to have done that....
so, if your tires are the same size you can try moving them to the front to see how it feels.
Tires and pressure can make a significant difference.
Now that I look really close I can see the bushing on the Trailing arms are in pretty sad shape on the bottom.
Is that something I want to do or just send it out?
Do I have mine rebuild or purchase new ones?
Other then the u-joints what else should I replace while I'm there?
That MAY be just the rubber that is exposed and not necessarily a bad bushing.
Use a big screw driver or pry bar and see if the trailing arm moves side to side.
I figured before I went much further to take the tires off and confirm that the bushings are the problem. I used a small crowbar and as you see in the video I don't see any movement. Did I miss something? Is the trailing arms the problem or should I be locking somewhere else?
Rear Suspension Issue.
