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My 67 vette rear U joint has started thumping against the fiberglass in the rear tunnel under a load ie gassing it just a little. What could be the problem. Thanks larry
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Re: 67 rear driveshaft U-Joint problem
Larry-----
The problem is likely caused by a fractured rear floor pan. This is a VERY common problem for mid year Corvettes. You can obtain a booklet from Paragon which describes the problem and the repair procedure. The booklet, as I recall, is very inexpensive and you NEED one.In Appreciation of John Hinckley -
Re: 67 rear driveshaft U-Joint problem
The rubber biscuit in the front rear end mount has been destroyed or come out. This allows it(rear) to turn-up when torque is applied. A very common problem on C-2 and C-3 Vettes.Comment
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Re: 67 rear driveshaft U-Joint problem
Wayne I think you are correct the rear rubber bushing has broke into and is squeezed out somewhat. Thanks LarryComment
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Re: 67 rear driveshaft U-Joint problem
When it goes completely, it leads to a loud clunk when the metal hits metal, sounds like you have a severely worn cross pin in the differential. This small bushing takes a lot of abuse, depending on how you drive....CraigComment
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Joe L; Would you mind......
giving me an "in a nutshell" explaination of what the Paragon procedure is?Comment
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Re: Joe L; Would you mind......
Frank-----
It's been a long while since I looked at it and I can't seem to find the booklet around here. In any event, what happens on mid-years is that the rear floor cracks and "sags". This causes the driveshaft to contact the floor. The Paragon-designed repair (actually, developed by Dick Fortier, former owner of Paragon) shows how to re-align the broken panel, add reinforcement, and complete the fiberglass repair with a traditional FRP repair process.
I've seen a LOT of mid years that suffer from this problem when I used to "hang around" a friend of mine's Corvette shop. In many cases, the problem is "sub-acute". In other words, it's present, but it hasn't developed symptoms that the owner's noticed as yet. It's progressive, so it will get worse as time goes on.In Appreciation of John HinckleyComment
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Re: Joe L; Would you mind......
Joe - do you know where the fracture occurs, I would like to examine my 66 and 67.....thx!.....CraigComment
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Re: Joe L; Would you mind......
Craig-----
It's hard for me to describe beyond what I've already said. However, I would suggest getting the Paragon booklet. It's very inexpensive ($5.00) and is their #8349.In Appreciation of John HinckleyComment
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Re: Joe L; Would you mind......
Thx Joe, sounds like a plan and a good investment....CraigComment
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Re: 67 rear driveshaft U-Joint problem
Larry,
I experienced a similar problem on my 66 convertible. It turned out that some of the rivets that hold a metal reinforcement to the fiberglass floorpan had sheared. This metal reinforcement is located right behind the seats on the inside of the car and goes across from door pillar to door pillar. I slightly enlarged the rivet holes and put in stainless steel bolts in their place. The hard part was getting enough clearance under the car to slip the bolts in between the frame and undercarriage. Also, I used a floor jack and some two- by-fours to bring the floor up to proper height before replacing the rivets.
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