[tech69]

we got a 78ish vette with a clear rubber bumper with the usual warpage near where it mounts. my idea is to use panel adhesive on the backside to stiffen it up, then some rubber bumper repair for severe lows, then a flexible filler on top. I'm hesitant to try to get the shape back with heat as it might want to sag back down again. i'm thinking it might be better to let it be and fill knowing it's settled. not sure if the bumper uses the vette style wavy washers as i didn't take it off. does it need those washers?

please don't respond if you've only read how this is fixed, cause I'm not fixing this in theory.

 

[TucsonJay]

I've been restoring and painting 'Vettes for about 40 years.

The early urethane and plastic parts of the '70s were plagued with problems.

Save yourself headaches... and solve the problem forever. Buy a fiberglass copy of the bumper.

 

[tech69]

we did but we realized it would have required more work to get it to fit right. The original fit well.

 

[mike the painter]

I've never done a vette bumper but I've had great success with using heat on newer bumpers the trick is having cold water(wet rags) to cool it quick while your pushing up on the low spot. Most times you can get some serious dents out and not even have to repaint and dont heat the painted side,I heat the back side while my hand is on the painted side so I can tell how hot its gettin..

 

[tech69]

yeah but the problem with that on this job is that it might want to resettle back to the sagging position, that's why I elected to leave it alone, figuring it can't sag anymore. :mwink: If there was more room between the reinforcement and bumper I'd do that cause then I could beef up the backside more but space is limited back there. Also thought about putting a crap load of panel adhesive on the backside, taping it while wet, then throwing it on the car. That way I'd end up with the most I could possible have without it conflicting with the reinforcement..

Do you know if they use those wavy washers for the front?

 

[69 widetrack]

In 1998 I did a 77 Corvette with the same problem, I was fortunate enough to have a large hot water tank with a temperature control (a friend of mine owned a chroming shop and they need hot water for rinsing) that I could drop the whole bumper into...when it came out I had 2 pieces of metal and body panel adhesive ready. I applied the body panel adhesive and the first piece of metal to the underneath of the warped bumper and put the other piece of metal on the top of the bumper and clamped the 2 together...let the adhesive cure, bolted it to the vette and it took minimal repair to the bumper after. I haven't seen the car for a few years now but I know it has lasted for over ten years....longer than the original.

Hope this helps Henry. The hard part here would be to find that tank.

Ray

 

[MARTINSR]

we did but we realized it would have required more work to get it to fit right. The original fit well.

You either have a bunch of work making the urethane one not warped, or you spend a bunch of work making the fiberglass one fit, both require a bunch of work.

The fiberglass one is permanent. The urethane, maybe not so.
I know you are above this "Basics" but something may be of use. Fiberglass Part Fitting - Autobodystore Just be sure to tear the mat like Randy taught us! (damn that's a good trick).

Brian

 

[tech69]

In 1998 I did a 77 Corvette with the same problem, I was fortunate enough to have a large hot water tank with a temperature control (a friend of mine owned a chroming shop and they need hot water for rinsing) that I could drop the whole bumper into...when it came out I had 2 pieces of metal and body panel adhesive ready. I applied the body panel adhesive and the first piece of metal to the underneath of the warped bumper and put the other piece of metal on the top of the bumper and clamped the 2 together...let the adhesive cure, bolted it to the vette and it took minimal repair to the bumper after. I haven't seen the car for a few years now but I know it has lasted for over ten years....longer than the original.

Hope this helps Henry. The hard part here would be to find that tank.

Ray

nice! The metal strip thing sounds like a good idea. so it sounds like the bottom piece was adherred to the adhesive and left in there? that sounds solid! I'd rather do that then making some pos aftermarket bumper fit. less work

 

[69 widetrack]

Yes, I left the metal on the underneath there for good, like I said, I saw it about 10 years after the initial repair and it stayed straight...I don't know if this would work in your case but it sure held when I did it. Also, like I mentioned, the repair on the finish side was minimal, and I think heating the bumper in the water tank helped a bunch...much easier to to keep the top surface straight when I applied the adhesive and the metal reinforcement strip.

Ray

 

[MARTINSR]

I don't think it would care how it got hot. :mwink: Henry, maybe a little lovin may work? :mwink:

But maybe a heated booth or simply an infrared heatlamp would get the job done?

I know I have repaired urethane bumpers with them.

Brian

 

[69 widetrack]

Your right Brian...it wouldn't matter how it got heated...I had the tank available and what I liked about the tank was that I had even heat over the whole bumper..rubber bumpers have memory and I felt that if I was able to heat the entire bumper I would have a better chance of getting it where it needed to be...but I'm sure any kind of heat would help.

I also forgot to mention Henry, I used my bead roller and ran to small beads on the metal that was glued to the inside of the bumper...I don't know if your planning to use this method but if you do, this additional piece of information may be of value.

Ray