79 bounce?
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 22
Likes: 0
79 bounce?
Hello,
I purchased a 79 that has been sitting since 99 with the original tires still on it. While taking it for a ride the drive train is very noisy along with a bouncing feeling as we were going down the street. I know the tires should be changed but what else can cause this feeling that's coming from the rear.
I purchased a 79 that has been sitting since 99 with the original tires still on it. While taking it for a ride the drive train is very noisy along with a bouncing feeling as we were going down the street. I know the tires should be changed but what else can cause this feeling that's coming from the rear.
Pro
Joined: Mar 2015
Posts: 681
Likes: 31
From: Nebraska
There are a lot of things that can do that. Until you get tires, about all you can do is give it a good visual. I am having a similar issue right now (although it doesn't sound as severe as your situation) and until I know the tires are good, I can't really do any real diagnosis.
Melting Slicks
Joined: Mar 2008
Posts: 2,989
Likes: 198
From: Meriden CT
The spindle doesn't rotate, you probably couldn't even tell if it was bent. The bearings are bad/loose, or there's some kind of debris between the rotor and the hub if the rivets are no longer in them, or the rotor is out of true. I wouldn't drive it with tires that old.
Pro
Joined: May 2008
Posts: 582
Likes: 9
I agree with not driving it on old tires. I had tires that only had about 4000 miles on them and we're just a few months old before I stored the car for 4 years. Tires looked fine when I took it out but about ten miles of driving the right front tire came apart. I was lucky that there was no damage to the car. Also from what I understand the rear spindles are not forged like the front for 79 so it's easy to bend them and although my car went to 125,000 miles before I had a bearing problem I was told by vette brakes and van steel that the rear bearings usually have problems with a lot fewer miles than what my car had on it. I think the number was something like 80,000 miles. I have a friend that had a hop or bounce in the rear of his 1980 vette and it was a bent half shaft.
If the runout is so much that the roter is not turning I would suspect a bent spindle.
If the runout is so much that the roter is not turning I would suspect a bent spindle.
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Team Owner
Joined: May 2001
Posts: 87,302
Likes: 1,583
From: Western NY
Hello,
I purchased a 79 that has been sitting since 99 with the original tires still on it. While taking it for a ride the drive train is very noisy along with a bouncing feeling as we were going down the street. I know the tires should be changed but what else can cause this feeling that's coming from the rear.
I purchased a 79 that has been sitting since 99 with the original tires still on it. While taking it for a ride the drive train is very noisy along with a bouncing feeling as we were going down the street. I know the tires should be changed but what else can cause this feeling that's coming from the rear.
The tires are probably "square" by now. Replace them first, then we can discuss things like shocks, out of balance driveshafts/half shafts, etc, that might be part of the problem....
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
Not likely the tires. Flat spot on the tires makes a thumping sound, not a bouncy ride.
The shocks can be tested without replacing the tires first.
The shocks can be tested without replacing the tires first.
Last edited by Priya; Sep 7, 2015 at 04:09 PM.
Instructor
Joined: Jun 2009
Posts: 175
Likes: 9
From: Plainfield IN
Hello,
I purchased a 79 that has been sitting since 99 with the original tires still on it. While taking it for a ride the drive train is very noisy along with a bouncing feeling as we were going down the street. I know the tires should be changed but what else can cause this feeling that's coming from the rear.
I purchased a 79 that has been sitting since 99 with the original tires still on it. While taking it for a ride the drive train is very noisy along with a bouncing feeling as we were going down the street. I know the tires should be changed but what else can cause this feeling that's coming from the rear.
Team Owner
Joined: May 2001
Posts: 87,302
Likes: 1,583
From: Western NY
Old, dried out tires will NOT provide a proper or safe ride. They most likely are a large part of the problem, and have to be replaced anyway, so why jump ahead to replacing the shocks? Since the car has been sitting for SO long, the shocks haven't seen any motion, they might be OK, at least for the short term, whereas the tires won't be any good at all. Therefore, you replace the OBVIOUS bad parts FIRST, eliminate them from the equation, then trouble shoot from there.
In all honesty, the brake calipers are probably questionable too. I'd inspect/rebuild/replace them, before going after the shocks.....
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
I'm surprised you don't know that leadfoot. You go to each corner of the car, press it down and watch it rebound. If it comes up and stays the shocks are good, if it comes up and bounces the shocks are bad.