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Hi,

First post here... have a 1979 Car.

The front and rear bumper covers are in need of some love.... minor repair and re-paint,... or replace.

I was successful in removing the front cover but,.... don't have a clue how to remove the rear one. Do the mufflers and fuel tank have to be removed to access all of the cover attachment points?

What is a safe product to use to remove the paint on these bumper covers?

Thanks,
Lee
 

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Hi Lee. I'm certain you will have to drop the tank to get to the rear cover nuts. I don't think there is any way to reach them otherwise. I don't know about the exhaust system, depends on how many times it has been replaced or modified. Mine is an 81 but the mounting should be the same or very close. The tank is not that difficult to drop, just try to run it very low or out of gas, that way the weight of the tank is manageable. I've done it by myself but it's a lot easier if you can get a friend to help. You will find a bunch of 10-24 nuts that screw on to studs around the perimeter of the cover. These nuts are called SEM nuts, meaning there is a "floating" washer attached to the nut. The washer has a slight conical shape. Don't lose them, and spend some time cleaning them up so that the washer is free to rotate. I searched high and low for new ones and I don't think they are available. I ordered some from one of the popular Corvette restoration suppliers and got serrated flange nuts, not the same thing at all. Don't use them, especially if they are serrated. The correct nuts are necessary for 2 reasons: First, the conical washer, about 5/8" in diameter, spreads the load out and away from the center of the stud. Second, when aligning and snugging up the nuts, the washer will not turn as you tighten the nut thereby making alignment a lot easier. I have a workaround for new nuts/washers, it's kind of a pain but works very well. If interested just let me know and I'll post how I did it.

I don't trust any chemical to remove paint from the bumper. I used the DA on areas I could get to with 150 - 220 grit discs. Then I wet sanded areas I couldn't get to with the DA, then finish wet sanded the whole thing with 320, then 400. If your bare cover is yellow, it will be made of polyurethane and will have the letters "PUR" molded into the bumper somewhere on the back side. This is a thermoset polyurethane material, whereas newer vehicles use a thermoplastic material. PUR material is difficult to "weld" together, unlike the newer thermoplastic material. I much prefer the repair process using the 3M system. To see how it works, check #121 in my post.

If you are lucky you won't have any damage to repair, but don't be surprised if you uncover some old damage, cracks, or a previous repair that needs attention. Let us know how it goes!
 

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Update to my post: You've got me thinking about this, especially since I'm at the stage of my rebuild to re-join the body and chassis. Today I tried a few things with the rear cover and confirmed a few things. The chassis with the inner bumper mounted will definitely not fit up into the body with the cover installed. I did notice that there is a significant gap between the inner bumper and chassis. I tried to take a picture of it but it doesn't really show the actual shape of the gap. It might be possible to reach the 10 screws that run across the top of the cover. I'm going to try it tomorrow, will let you know. There are a number of advantages to leaving the fuel tank installed on my project. This is a resto mod so there are more/different connections to the tank than stock. Plus, I've always liked to fully pressure test the fuel system before setting the body on. So leaving the tank installed would be better for me. Also, I'll clarify what I said about the screws/nuts that attach the rear cover. There are 10 screws along the top edge of the cover. They are #10 self drilling sheet metal screws, 5/16" hex head, about an inch long. There are 4ea 10 x 24 studs on each side of the cover. These are the ones with the unobtainable SEMS cone shaped washers made onto the nut. There should be a picture of the 10-24 SEMS nut and my workaround. I used a stainless steel #6 fender washer, drilled out to fit over a #10 screw along with a stainless 10-24 nut. I made the cone shape with a steel ball, about the size of a marble, by putting the washer over a socket or short metal pipe and squeezing them in a vise. It's 2 piece, unlike a real SEMS washer. Kind of a PITA but works just fine.

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Ok, here's what I found today. The hex head screws that attach the upper portion of the cover can be accessed from the bottom between the inner bumper and the rear of the frame with the tank in place. It isn't easy but can be done, at least on my 81. I checked the 79 assembly manual and while the bumper and bumper cover are different, it looks like the space is there. I'd recommend spraying some penetrating oil on all fasteners, they are usually pretty cruddy. Here's a picture looking up from the bottom the best I could. There is also a picture of a handy tool for the screws, it's an Xcelite 5/16" miniature nut driver compared to a standard size driver. I don't know if Xcelite is even still around, I've had this set since 1970. (Yes, I'm that old!) But I'm sure somebody makes something similar. Good luck!

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