R Cab... Roof Repair Or Just Replace?

[Lmackattack]

My RS had a roof mounted AC unit. When I bought it it had a plate bolted to the roof in its place. I half assed patched that but now under the rain rails its starting to rust/bubble where the roof meets the cab sides. Is it better to replace the whole roof or can I just make a repair under the rain rail? If I make repairs I dont know if the rust will continue to spread? If I remove/replace the whole roof and let some por15 get down in the insides it may slow any rust issues down the sheet metal.. never done this before.

Trent

[Rob]

My RS had a roof mounted AC unit. When I bought it it had a plate bolted to the roof in its place. I half assed patched that but now under the rain rails its starting to rust/bubble where the roof meets the cab sides. Is it better to replace the whole roof or can I just make a repair under the rain rail? If I make repairs I dont know if the rust will continue to spread? If I remove/replace the whole roof and let some por15 get down in the insides it may slow any rust issues down the sheet metal.. never done this before.

Trent

R model roofs are a lot like a Jeep CJ. If you can see rust on the outside. It is much worse on the inside.

This is of course based on my limited experience with the model........

There can be a real can of worms under that skin. The attached photos show common rust areas from both leaks, and roof air units.

Roof skins aren't cheap by any means. I think they run about $600.00 if memory serves. Not too bad of a job just be sure to use a weld through primer, and dump enough rust preventative material into the area from the interior and you'll be fine. Then use a "self leveling" seam sealer in the rain gutter or trough to ensure water doesn't creep under your good work.

You could of course glue the skin down with just a couple of plug welds at all corners but I stick with welding them solid. I've seen too much glue break, or fracture as it does not dry flexible.

Rob

[Frenchy Mack]

Hello everybody,

An friend of mine buy an French DM 685 SX built in 1972. Here is the pictures

As you can see, the rust has made his bad work. So he decide to change the cab but in France it is very difficult to find one. But the miracle exist. more pictures later.

greatings

Erwan

[57 bcr]

Trent,

Replacing the roof panel is an ordeal from what I've been told.But one you'll be glad you did,once your done with it.The guy that painted my truck says he'd rather replace a roof, than to try and straighten/repair it.He also warns against Por-15.It's a good product but not to be used before final painting is done,unless its far away from the sheet metal to be painted.He experianced this first hand while painting a beautiful vintage Dodge wagon for a customer.The guy had painted his inner fenders with POR-15.When the painter went to shoot the outer fenders,the paint ribboned as if somebody poured brake fluid on it.It was the fumes coming off of the POR-15 that screwed the paint up.The customer had to take the inner fenders out, then painter then was able to repaint the outers with no problem.I guess its just the volotility of the POR-15 that messed the paint up.Just a hint, by no means am I saying POR-15 is a bad product,it just has to be handled with some thought. Al

[ducky698]

Trent,

Replacing the roof panel is an ordeal from what I've been told.But one you'll be glad you did,once your done with it.The guy that painted my truck says he'd rather replace a roof, than to try and straighten/repair it.He also warns against Por-15.It's a good product but not to be used before final painting is done,unless its far away from the sheet metal to be painted.He experianced this first hand while painting a beautiful vintage Dodge wagon for a customer.The guy had painted his inner fenders with POR-15.When the painter went to shoot the outer fenders,the paint ribboned as if somebody poured brake fluid on it.It was the fumes coming off of the POR-15 that screwed the paint up.The customer had to take the inner fenders out, then painter then was able to repaint the outers with no problem.I guess its just the volotility of the POR-15 that messed the paint up.Just a hint, by no means am I saying POR-15 is a bad product,it just has to be handled with some thought. Al

Hi, my chassis is painted in por15, it has no UV protection at all, then I painted over it in 2 Pak

Grant

[Rob]

Hi, my chassis is painted in por15, it has no UV protection at all, then I painted over it in 2 Pak

Grant

POR-15 is a very good product but as Grant said it has no UV protection built in. It must be allowed to "gas out" before topcoating with a final color or it will do as Al stated; BTDT. I use a product called "Chassis Saver". It is just as good as the POR-15 but costs quite a bit less. It also doesn't "chalk off" near as bad as the other product when the sun hits it.

Rob

[ducky698]

POR-15 is a very good product but as Grant said it has no UV protection built in. It must be allowed to "gas out" before topcoating with a final color or it will do as Al stated; BTDT. I use a product called "Chassis Saver". It is just as good as the POR-15 but costs quite a bit less. It also doesn't "chalk off" near as bad as the other product when the sun hits it.

Rob

mine chacked off with in a month. its good stuff tho, had fun trying to get it off me! went over it with 2 pack so that chassis shouldnt have a problem

Grant

[Lmackattack]

good info guys, thanks....when I got the truck the roof had a few rust spots and I did some local repairs, now some more have showed up and I know its going to be a little ugly behind it. the only other places the truck has some issues is around the rear window, door bottoms and a few small spots behind the lower door molding. I would like to save the cab now and not have to replace it 10 years down the road... what do you figure a body shop would charge to do the roof work? this is if I had the cab gutted and ready to work on?

[Rob]

good info guys, thanks....when I got the truck the roof had a few rust spots and I did some local repairs, now some more have showed up and I know its going to be a little ugly behind it. the only other places the truck has some issues is around the rear window, door bottoms and a few small spots behind the lower door molding. I would like to save the cab now and not have to replace it 10 years down the road... what do you figure a body shop would charge to do the roof work? this is if I had the cab gutted and ready to work on?

Bring it down here, I'll work with you on it. If you hire it done it will be expensive as if it's in as good of shape as mine, probably $1800.00 or so.

Lot's cheaper if your willing to do the "grunt" work with guidance.

Rob

[ducky698]

good info guys, thanks....when I got the truck the roof had a few rust spots and I did some local repairs, now some more have showed up and I know its going to be a little ugly behind it. the only other places the truck has some issues is around the rear window, door bottoms and a few small spots behind the lower door molding. I would like to save the cab now and not have to replace it 10 years down the road... what do you figure a body shop would charge to do the roof work? this is if I had the cab gutted and ready to work on?

Hi, and you can still buy all the panels from mack.

Grant