Bought this regular cab pickup.
Knew it had this issue on the surface of the roof, but did not realize how bad it was.
Even if I did know the extent, I still would have bought this.
I would like to know what the best approach to patch this would be.
I am not wanting show room quality, I just don't want water to get through and pool underneath the (future) paint (job).

A friend that has done some restorations before speculated that a former owner dropped something on the roof and patched it with something, and that I'm seeing the age of that patch failing.

The drip channel above the doors and about about three inches in from the edge all the way around the roof looks good, no cracks.
It was in the desert, so the rust that is visible in the photos is just on the surface, so far as I have found.

Any ideas of how to patch this?

One thought I have had is to spray a light coat of rust reformer, then bondo it.
I realize the center of these two voids exceed the thickness of what bondo is made for, but my thinking is this is a horizontal surface.

 

That's a TON of bondo, you would be better starting with a new cab, a lot less work.

 

Whoa! That's ridiculous. Any filler used that thick will eventually fail just like that. You gotta first push it out as much as possible. If there are no hard creases in the roof panel, it'll probably push out fairly easy. Pull the headliner and look for bent roof supports, if there are any, push those up. I'd use a bottle jack and length of 2x4 with a short length across the end like a "T". Hammer on any bends you can see while jacking to relieve stress. Be careful not to hit the roof panel or you'll put dents in it, hit the supports. I'd be willing to bet it'll mostly come out with that. If there's no support in the middle, push it up by hand in the middle of the dent and have someone go around the dents outside edges lightly tapping with a softer rubber mallet. Either way, should be able to get it pushed out close to stock. Once you get it close, sand the outside clean, wash it with something like lacquer thinner or acetone. Let that fully evaporate, then spread filler, if it needs it. I don't like more than a skim to even things out, the thicker it gets, the more prone to fail. Smooth it out, prime, block sand, prime and block sand again If needed, seal, paint. If it's not a show truck, I'd take a slightly wavy roof over filler up there, but that's me.

 

100% agree. Every time I wash my truck or when I was polishing the oxidation off, that roof section warps and pops in pretty easily. It pops right back out once you take the tension off, but the warping could easily crack any bondo you put up there and you will be right back where you are now. Maybe around the outer edges where it doesn't warp as much, but definitely avoid the center of the roof if you can. If not, be careful washing and waxing up there.

 

I unscrewed the headliner on both sides. Driver's side and roof support are fine. Passenger side has an L shaped tear that has been welded or soldered back together... it looks like whoever did it just wanted it not to leak.

I am going to live with it for now and try bondo'ing it. Worry about replacing the cab later.

 

did you push the outer roof panel back up into shape?
If so how far from the inside cross brace is the roof panel?
Something is not right if they had to add that much bondo to the roof.

BTW if there are no cracks in the metal roof it will not leak. What will happen water & dirt will get between bondo and metal roof and rust a hole in it and leak.

Push everything back up into place. Removing that old bond will help with that.
Once in place and old bond removed treat the rust, thin coat of bond and fish it with paint.
Dave - - - -

 

I have not tried pushing on it yet.
The roof over the cross brace is in the original shape that I could see.
The dent/tear seems to be more over the passenger side.

That is my thought, that I want to seal as good as possible to prevent it pooling underneath the paint.
At least long enough to decide what I want to do with it.

 

You are lucky the roof panel is only 1 layer and you can push the outer layer from inside.

On my 81 I am not that lucky as they made them 2 layers with about a 2" gap between them.
It looked like someone sat on the roof, caved it in, tried to pull it out with a screw type dent puller and bondo like yours.
I had to take the roof down to bare metal as water got under the bondo and rusted pushing the bondo up and cracked it.

Once I got to bare metal I used a dent puller you weld studs to the panel and pulled it back into place the best I could.
It has some waves but the outer layer kept pushing in when trying to sand it.
Besides it's not a show truck and no one will see the roof unless they get up into the bed.
Studs welded into place. The dark color of the roof between the studs is rust.


After I pulled the dents and a little hammer on the high spots you cut the studs off, grind down what is left.
I tested the rust with acid for 48 hours then rinsed it off and did my bondo thing till happy and got it in primer.

edit: I also used spray foam that expands between the 2 layers. I went in thru the light opening above the rear glass and the 2 sun visors.
This should do 2 things: 1 insulate the roof from heat & cold (mostly sun heat) and 2 stiffen the outer roof panel.
Dave ----

 

nice! looks like it turned out well

 

Thanks it should be good enough for a nice looking driver and that is all I am looking for.

To tell the truth this project was not to be a frame off rebuild but being a ex-body man with OCD I could not do half azz job and why it went the way it did.
Had to replace the floors, rockers, cab corners, rear door posts and inner & outer left door. I also swapped fire wall so I could have AC.

A little more body work and should be ready for paint, as it sits July 4th.

Dave ----

 

I have two cracks left to chase.
All of the brown looking rust is at the surface and requires sanding to scrape off.
Once I cut enough back I get to clean metal.
I bought some epoxy for a different project, and plan on using part of that on this patching.

The roof over passenger side is firm, but I don't plan on putting my weight on it.
The pushing on the repair that I have done has not caused it to flex, and that is more pressure than I would use while washing / waxing.

I have been considering a cab swap. I have found two regular cabs, one from 1978, and the other from 1979.
So both have the shoulder belt that I would like to have.
Yet the truck I got is 1975 F-250 with 4x4, so it has the main gas tank behind the seat and an auxiliary below the truck bed.
If I swap cabs, could I dispense with the main tank, and run the gas line directly from the auxiliary?
Are the cabs different in clearance because mine is a highboy?

 

I've got a couple of ideas that are somewhat unconventional.

What is your final product going to look like? Be realistic, I've been "restoring" a '65 Mustang coupe for 31 years and it hasn't been touched in about 18.

Finished product, abilities and budget has a bearing on these ideas. I'm sort of a "do it right the first time" kind of a guy, but I'm not Bill Gates either.

 

Ahh, my first vehicle was an '82 F-100 4x4 flairside. 302/auto red with maroon on the sides, but not the roof. Single tube chrome rollbar, aftermarket chrome rear bumper with a drop hitch, hurricane mags and 31x10.5-15 tires. Got about 9mpg.

Had a chance to buy it back from the guy I sold it to about 10 years ago, economy sucked and it'd been parked in a field for about 10 years, I passed.

 

I want a daily driver that is not an eye soar, but it doesn't have to be show room quality.
I don't plan on selling it, so I will drive it until someone crashes into it or I die of old age.
I have a big budget, but little free time.
We have other cars, so this vehicle can be disassembled and we still have transportation.

The truck runs well, so the only things I want to achieve are:

patch roof,
paint body (preferably with glass removed)
apply rust protectant paint to as much of the frame that is possible
get new wheels
replace seating with the used bench seat and mounting hardware I bought

 

Okay, so my idea involves a donor roof and panel bond adhesive. I believe you could cut the roof out leaving an inch or so for the new roof to lap over.

Initially, I'd fit the new roof panel over the existing to size for fit and finish. I'd think a cab roof could be had pretty cheaply from a donor rusted out cab, or wrecked cab, maybe $50 if you sawzall it off yourself.
Then it's just a bunch of cutoff wheels and flapper wheels to fit up. I believe a series of ratchet straps to suck it to the cab would work.

The other idea involved the vinyl top look, via bedliner material.