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Alan,
The bumpers were exactly the same through 73. My weld nut wasn't welded on straight. Made it look different. However, for 73 they added an inner brace rod that attaches from the frame over to the side bumper bolt. The 73 AIM shows bolt, lockwasher, flat washer, brace on the inside of the fender. The rubber bushing (GM part # 6263571), goes in the hole from the outside. Here's a photo from the other side. I'm thinking this addition was part of the more stringent safety regs. starting in73.
Tooch
Tooch, do I understand you correctly that the hole through the fiberglass for this bumper attachment is the same size as the outside diameter of the rubber bushing (#6263571) and the rubber bushing goes through the hole in the fiberglass with part of it on the bracket side and part of it on the bumper side?
Reason I ask is because on Willcox's site they say "Installs on the backside of the fender between the rod and fender." which I understand to mean the rubber bushing does not go through the fiberglass, has a larger diameter than the hole in the fiberglass and is entirely on the inside of the rear quarter panel.
I'm planning on ordering six of these and using them on the four bumper mounting holes on the tail light panel as well. My husband expressed the concern that the body is attached with rubber mounts to the frame which will allow some movement of the body relative to the frame so if the bumper brackets go to the unmoving frame and the moving body/tail light panel this will cause stress on the fiberglass tail light panel where the bumper brackets attach. I would think if rubber grommets like these are used at all bumper mounting points and go through the fiberglass that would eliminate that potential problem.
Priya,
Yes, diameter was the same at least it was on my 73. It fit the hole in the fiberglass However, like I mentioned above I cut one in half because they were too thick and my original bolt wouldn't go all the way through everything to get to weld nut on the bumper. When installed you should just barely be able to see the bushing. Below are a couple photos showing how little you see of it on my friend's original 73....
Hope this helps!
Tooch
Hi 71 & P,
Here are the dimensions from the surface of the bumper to the beginning of the recess that the lenses fit into.
The right side is the same on this car.
I would expect these dimensions to vary slightly from car to car, and side to side…. but not so much that it would be easily noticeable.
Regards,
Alan
Priya, I can clear things up a bit with the rubber body mounts and the rubber washer on the 73. No one stated that the 68-72 Corvettes are the only ones with solid aluminum body mounts.
GM went to steel belted radial tires on Corvettes in 1973. They felt that the new tires had too much road harshness and changed the frame to accept the thicker rubber two piece body mounts. Since the
73 is the only rubber body mount C-3 with metal back bumpers, they must have added the brace and rubber washer to help prevent body cracking. I hope that this clarifies things up a bit..
I ended up here while reading Doorgunners thread. I have no idea what they did with the C2's. They had rubber body mounts and metal bumpers. Lou.
The additional brace was added in 1972 and continued in 73. 1971 and earlier did not have this brace from the frame to the outboard bumper mount. Photos shows the left and right brace on a 6500 mile 1972.
02-25-2017, 06:35 PM
