Rear leaf spring bushing would be my "guess".
[C1] Clunk in rear when accelerating?
Thread Starter
Instructor
Joined: Jul 2021
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Clunk in rear when accelerating?
1962 250hp, Powerglide. Just went to a cruise-in tonight about 50 miles away and noticed that when I accelerate from a stop in a spirited manner, I get a clunk in the rear about 2 seconds later. Sounds like left rear to me. What should I be looking for when I get under the car? Non posi axle.
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My first thought is of a rubber bushing which is shot and which allows something to move which shouldn't.
If the steering momentarily feels "funny" when you hear the clunk, you might look at the leaf spring bushings.
OTOH, if there is no momentary steering funny business, the clunk might be coming from one of the radius rod bushings.
That's my $0.02, offered at a 100% discount.
If the steering momentarily feels "funny" when you hear the clunk, you might look at the leaf spring bushings.
OTOH, if there is no momentary steering funny business, the clunk might be coming from one of the radius rod bushings.
That's my $0.02, offered at a 100% discount.
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St. Jude Donor '09 thru '26
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If they were bad, the U-joints would clank/clunk when shifting from fwd to reverse with the brake engaged. It used to be an easy way to check out the condition of the drive line on a PG car back in the day. You could also check the engine mounts by holding the brake and applying power in both fwd and reverse, as it caused the engine to lift. Silly HS trick, but it worked.
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Update
Spent a couple hours under the car today and at my age that is all I can manage. Here is what I found: All the rubber bushings are intact and look like new. Wheels have no play sideways or up and down ( original steel wheels/hubcaps). Universal joint had about a quarter turn play in one of the u-bolts (tightened) and no play. Right rear tail pipe was a little loose. (tightened). Differential was down on lube an inch or so. Bolts tightened and lube up to filler hole. Car has 8K miles on a frame off older restoration and still looks excellent underneath.
On my test drive it seems like the clunk on acceleration went away BUT I now get a loud clunk when I get off the throttle between 30 and 40 mph. Sounds like someone hitting the floorboard with a large hammer. This may have been present all along, but the car has not been run this hard in 30 years and I normally don't run it this hard either. Started to rain and I did not know what to check next, so I quit for the day.
P.S. One of my test runs was on a tar and stone road. Left around 200' of rubber and smoke. Most fun I've had all week!
On my test drive it seems like the clunk on acceleration went away BUT I now get a loud clunk when I get off the throttle between 30 and 40 mph. Sounds like someone hitting the floorboard with a large hammer. This may have been present all along, but the car has not been run this hard in 30 years and I normally don't run it this hard either. Started to rain and I did not know what to check next, so I quit for the day.
P.S. One of my test runs was on a tar and stone road. Left around 200' of rubber and smoke. Most fun I've had all week!
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Maybe you've already answered this but: Have you made the thing go clunk while holding your hand on the shifter? Can you feel the clunk through that shifter? It might help pin down whether it's in the drive train or body or..... not a silver bullet, but one more clue which might help.