When did they start putting the round brace to the bolt on the side bolt of the rear bumper? My 72 only has on e on one side. I don't remember them on my 70.
Round rear side bumper brace
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Re: Round rear side bumper brace
The fact that you have such a brace on only one side is fishy. On (late) 70s, the only "round" brace is to the lower inboard mounting bolt near the license plate. My observation matches the 70 AIM, UPC 14, Sheet B1. An examination of the 72 AIM will answer your question.
Last edited by Chuck S.; January 13, 2011, 07:53 PM.- Top
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Re: Round rear side bumper brace
It's very hard to make out what that is in the lower right corner, but I think it's the frame side rail in the very corner of your photo.
The outboard bumper mounting hole is off the photo.
I notice that the 72 inboard mounting bracket does look different from the 70; it appears to be one piece, where the 70 consisted of two heavy duty pieces bolted together. I'm not sure why they did it that way in 70; perhaps to make it easier to fine tune the bumper fit.
It's possible they changed the bumper mounting brackets in 72...the AIM will tell.- Top
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Re: Round rear side bumper brace
Keith are talking about the bumper bolt in the RT and LT quarter panel. The support mounts to the outboard side of the frame and then to the bumper. If you are I believe that all 73 Corvette had them along with a rubber grommet. They could have shown up on late 72's I know it is listed in the 73 AIM. The brace or support shows up on the last year of chrome bumpers you would have thought this would have shown up earlier. Ever shark has cracks at this mount point in the quarter panel great idea just way to late.
Paul 18046- Top
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Re: Round rear side bumper brace
This pic shows them not on the car. The previous owner had removed the bumpers but I don't know if he removed the braces. none of the others were removed.
Terry, I would be curious if your car has them as they are only a week apart.
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Re: Round rear side bumper brace
That shot appears to show that the side mounting hole has been filled, with no side bolt (or brace) being used. In my opinion, the fill was not done by the factory...the bonding adhesive used appears too dark, i.e. it is not aged with dust, etc.
It appears to also have a small hole remaining forward of the adhesive where the mounting hole was located. If you look closely, you may find some unrepaired cracking visible around that area. I suspect that during a repaint, a previous owner decided to simply eliminate the side attachment and bondo the exterior surface smooth. As someone said above, that area around the side mounting is prone to damage with low speed collision.
The outboard mounting bracket is the rectangular section bracket attached to the outside of the frame rail.Last edited by Chuck S.; January 13, 2011, 11:48 PM.- Top
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Re: Round rear side bumper brace
Hi,
My 71, 6589, didn't have the braces.
I found the same thing as Paul noted; the fiberglass area around that hole is often cracked. In restoring mine I found that using 2 washers helps the cracking situation because the single flat washer washer used in St. Louis is a bit too large in diameter for the concave area in the fiberglass it needs to mount against. I found a flat washer with the proper size hole but a smaller diameter and used it as a spacer to take the uneven pressure off the fiberglass. The original washer covers it in such a way that it can't be seen when the lock-washer and bolt are installed.
Regards,
Alan71 Coupe, 350/270, 4 speed
Mason Dixon Chapter
Chapter Top Flight October 2011- Top
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Re: Round rear side bumper brace
AT some time the PO decided he was going to "restore" the car. He took off the bumpers and attempted to repair the side holes. There is fiberglass around the hole. If Alans car doesn't have them I guess mine didn't either. I got everything he took off except maybe some bolts and don't remember the braces. I am glad the PO stopped when he did as I had the pleasure of taking apart and lableing everything else.- Top
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Re: Round rear side bumper brace
The fact that your 72 has ONE brace installed probably says it was built after the running change, and the PO simply misplaced the other brace before turning the car over to you. The actual production change would not have taken effect until at least weeks, maybe months, after the date of the revision.- Top
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Re: Round rear side bumper brace
Thanks Terry for your cold backside and verifying my 70 should not have the braces.
The change dated 1-26-72 refered to the added bushing. I assume the braces were already there. My 72 is an aug 71 car so maybe they were added at the beginning of production for 72s. Unless some 71s later than Alans show up with them.- Top
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Re: Round rear side bumper brace
I never noticed this when looking at Al Wagner's 72 ZR-1 do not remember the S/N but here is your support rod plain as day.
https://www.forums.ncrs.org/showthre...77292&uid=1443
Look at the 4th response and enlarge the 3 rd photo there is the rod from the frame to the fender. Now I have to say the last 2 years of production had the added support so maybe some late 71 had this support.
Paul 18046- Top
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