Too much flex in my roof

[Tagintexas]

I'm doing some body work on my 84 k20. It came with a pretty significant bird bath on the roof. I welded a stud on and pulled the dent, but the metal pops back in with very little effort. There's no way I'll be able to block sand it properly without it popping back in. I'm wondering if there is some structural reinforcement between the inner and outer shell that was compromised when the original dent happened and that's why it's so easily moved now. It's right in the middle of the roof. I'm considering a few shots of expanding foam in this area to make it rigid again. Thoughts?

 

[Honky Kong jr]

Sounds like metal fatigue. I know I would mane a spine that slid in from the inside that had the correct contour. Then drill a few holes in the roof and weld the spine to the roof and tack the spine to the inside. Reinstall headliner be good as new......well better.

 

[yevgenievich]

There is a beam on the inside that has body sealer type compound bettween it and the roof. Might also need to put some heat on the dent area to let the metal stay back in shape.(As it was deformed when dented)

 

[Honky Kong jr]

Applying heat is not a good idea unless you know what your doing, done incorrectly will yield an extremely wavy roof that will need lots of filler to correct. Just saying.

 

[74 Shortbed]

X2 on the heat, I would never attempt to do that, way too easy to distort it..

 

[yevgenievich]

That is correct that applying heat can ruin things, but that is the only way to shape the metal back in to the shape reliably in some situations. Making sure things are braced from below is probably more than good enough in your case

 

[HotRodPC]

I'm doing some body work on my 84 k20. It came with a pretty significant bird bath on the roof. I welded a stud on and pulled the dent, but the metal pops back in with very little effort. There's no way I'll be able to block sand it properly without it popping back in. I'm wondering if there is some structural reinforcement between the inner and outer shell that was compromised when the original dent happened and that's why it's so easily moved now. It's right in the middle of the roof. I'm considering a few shots of expanding foam in this area to make it rigid again. Thoughts?

Welcome to GMSB. I never thought of that before, but I sure like that idea of shooting some expanding foam between the layers. Not only add rigidity but quiet in heavy rain or hail. I'd say you could drill a hole in either the top of the bottom, shoot the foam, then fill and finish the hole.

 

[Tagintexas]

Thanks guys. I think I'll pop a couple 3/8 holes inside and try out the foam. Headliner will cover them up so it will be the least amount of work. I'll let you know how it turns out.

 

[Honky Kong jr]

Thanks guys. I think I'll pop a couple 3/8 holes inside and try out the foam. Headliner will cover them up so it will be the least amount of work. I'll let you know how it turns out.

Don't go crazy or it will go the other way

 

[bucket]

The metal is now stretched. When the dent is popped out, there is probably knots in the roof around the the perimeter of the dent. Lightly tapping those dents down with a body hammer (shrinking hammer would actually be ideal) should give the strength back to the roof skin.

Expanding foam should help too. But like what was already said, be careful. Also, moisture can make the foam expand even more later on.