Holy Roof Rust, Batman!

[ArnieJr]

So I pulled the trigger a couple of weeks ago and pulled the vinyl off my roof. It wasn't pretty. Vinyl covers a multitude of sins.
I hope I managed to at least stop the spread with some sanding and primer, but obviously gotta patch the holes. I know about as much about body work as any guy who's watched a few YouTube videos to be honest and not financially blessed at this point to leave it to a professional. So...
I bought some sanding blocks, long-hair fiberglass Bondo and adhesive body patches. The idea is to sand it down to bare metal (or nothing), primer it, stick the body patch on and then the Bondo. I'm not looking for pretty at this point, just stop the bleeding and minimize the leaks I already have (in addition to Flex Seal around the front and rear glass)
So for the Bondo, can this be done from the top (i.e. without removing the headliner?!)? A lot of videos show things like fender and quarter panel repair, where you can put the patch behind the hole. I plan to stick it over the hole from the top and then bondo over that.
Pardon my ignorance, I'm still learning.

 

[polara71]

OMG, ida packed it in right there.

 

[Samplingman]

Just my 2 cents worth, but it’s not just about leaks or beauty. The roof panel is the major structure of a unibody. Once perforated it is no longer a sound structure. Consider a donor roof or extensive patches to weld in. What year and model are we looking at?

 

[CBODY67]

In one respect, I would say "Forget the fiberglass", figure out how to remove the cloth headliner, and put all of your patch panels on from the inside, where available, using panel adhesive on the cleaned inner surface of the roof panel. Rather than "body shop coatings", I might suggest a rust encapsulator coating, THEN paint and primer as directed.

In the case of the C-pillar/roof seam, knock out the "flakes" and work from there. Encapsulating and then plugging the holes, then prime and paint.

Trying to approach things from the outside only might lead to more issues later on, needing more repairs that are worse.

Might even use something like J-B Weld to plug the smaller, cleaned-off, then encapsulated holes might work, too? Using some of the stainless steel tape as a backing for it.

Bad thing is that seasons are changing so working quickly and efficiently can be important.

Take care,
CBODY67

 

[Big_John]

So I pulled the trigger a couple of weeks ago and pulled the vinyl off my roof. It wasn't pretty. Vinyl covers a multitude of sins.
I hope I managed to at least stop the spread with some sanding and primer, but obviously gotta patch the holes. I know about as much about body work as any guy who's watched a few YouTube videos to be honest and not financially blessed at this point to leave it to a professional. So...
I bought some sanding blocks, long-hair fiberglass Bondo and adhesive body patches. The idea is to sand it down to bare metal (or nothing), primer it, stick the body patch on and then the Bondo. I'm not looking for pretty at this point, just stop the bleeding and minimize the leaks I already have (in addition to Flex Seal around the front and rear glass)
So for the Bondo, can this be done from the top (i.e. without removing the headliner?!)? A lot of videos show things like fender and quarter panel repair, where you can put the patch behind the hole. I plan to stick it over the hole from the top and then bondo over that.
Pardon my ignorance, I'm still learning.

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From my experiences with patched up rusty cars, I think you are going to make things worse with the Bondo. I've seen many cars have their rust "repaired" with Bondo and they always look a lot worse when you remove the Bondo patchwork.

If nothing else, strip off the spray bomb primer you've put on and either use an encapsulating rust paint like POR-15 or Eastwood's version (possibly better, never used it myself) before patching it.

I have done a couple small floor repair jobs with POR-15 soaked fiberglass mat (using the POR-15 rather than resin) and they were OK for what they were. Nothing that would count as structural or even cosmetic, but it would be a lot better than Bondo and aluminum tape.

As @Samplingman said, the roof is structural to the body and the best repair is to replace the roof.

 

[Justin Plant]

the inside of the metal is almost certainly as rusty as the outside. While sanding and priming is a good idea, the interior metal will need attention too. Just stopping the water from coming in? A friend of mine used Flex tape on a 150 gallon rinse tank on a chemical cleaning/suction truck. Worked like a charm. The weld had broken loose, he ran into Walmart slapped the tape on the truck and it has yet to leak. The tank is on a Freightliner, the vibration and weight of the water didn't faze it one bit. Try it, it won't be pretty but it'll work. Good luck!

 

[Just Carbs]

If you're not going to go cutting and welding, then it's going to be fiberglass. With epoxy resin preferred, polyester will do.

All the trim must come off. There's a tool for that, works good to.
Remove head liner, seats and carpet. Cover dash.
Metal tape holes from inside cabin, truck and dash.
Then paint ALL the rust with molasses, from the farm feed store, by the gallon.
Cover the molasses with plastic so it doesn't dry out. Wait, wait, wait.....and wait some more. Peel the plastic back and work the molasses around as often as you can. One day, two days, five days, 2 weeks. Wash, rinse, repeat as needed. Molasses will not attack anything but the rust. It's slow but very effective. It will eliminate "all" the rust, in time.
Lay fiberglass cloth "not" mat over the top and glass channels as needed.
Treat inside with PO-15 rust converted.
Prep, paint, reassemble, and forget about it.

Now, if you don't require a permanent repair, just PO-15 everything, reassemble, and call it good.

 

[CBODY67]

Be sure to keep the molasses tightly-capped so that the insects and critters don't find it.

 

[57fury440]

If it was mine, I would replace the roof.

 

[CBODY67]

Certainly, replacing the roof can have its pitfalls, too. One is cost and finding a body shop willing to do such. If a shop is not scared of the project, their customer might be scared of their charges to do such.

It would be nice to find a suitable donor car, too, but without having ever had a vinyl roof on it to start with. Which THEN might raise the question of whether or not just finding another car might be the best solution? In which case doing a "DIY Fix" on the current car would be more justified, in the short term. I fully understand that financing such a "second car" might have it's pitfalls, too!

I also understand that a particular demographic of people are concerned about "reliable transportation" rather than cosmetics, so selling the DIY-Repaired car with that orientation would be necessary. Selling the car based on its basic great reliability and "easy to repair" (compared to a more modern vehicle!) attributes. Considering the size of the trunk and rear seat space, it might serve some workers as job-site transportation, especially if they might need some protected hauling space? While getting similar fuel economy to many 1/2 pickups of older model years.

It would be nice to put a new roof on it, but I highly suspect doing so might be financially not viable, all things considered. IF a good donor roof was found, how to transport it, then install it would certainly cost more than the current car would ever be worth, I suspect. Which would mean doing good DIY repairs while also keeping a keen eye out for a replacement vehicle without a vinyl top, from a drier climate. Then find somebody who needs some basic transportation, not terribly concerned with cosmetics, and go on down the road. MIght even donate it to one of the "cars" charities?

Take care,
CBODY67

 

[azblackhemi]

This is the proverbial "Between a rock and a hard place" I agree the roof panel and maybe some of the structure should be replaced. I also agree how difficult it would be as mentioned above to locate, ship and find a shop to do the job. If only we had aftermarket parts for our cars! Good luck on whichever way you go.

 

[bigmoparjeff]

Considering the size of some of the holes, I think the best plan would be to use fiberglass cloth to cover them up. You can get a small kit at any auto parts store that will come with resin, hardener, and some cloth. This will give you the thinnest "covering" over the holes, and it's pretty sturdy once set up.

As you said, you're looking to try to preserve things or at least slow down the rust process, and I think this is the most practical route. It won't last forever, and you'll likely need to touch things up every few years. No need to mess with the headliner, just do it all from outside. Grind out as much of the rust as you can and clean things up with the round wire wheels that you can chuck in a drill. I strongly recommend actually measuring the resin in ounces and stick with the 10 drops per ounce. It can be a bit poky to start setting up, but it will. Once the glass mat has hardened, you can sand it smooth and apply a coat of filler over top to blend the edges in with the surrounding metal. I did a similar repair on the doors of my old Ford dump truck 20 years ago and the repair hasn't reached a point yet where you would say that it's failed. It has some bubbling, but the rust hasn't poked through the glass mat yet.

Having much experience with these cars, I'd expect that you have quite a bit more rust hiding down in the window channels, and it would be a huge and expensive job to completely repair all the rust permanently. These days, it's close to impossible to find a professional shop that wants to get involved with this kind of job, so it's really up to you to decide what you can do to preserve it as long as you can. The best favor you could do for the car would be to get one of the metal, free standing carports to keep it out of the rain as much as possible. Unfortunately, fusey's are leakers, and it's really tough to keep the water out of them.

Jeff

 

[bigmoparjeff]

Also, I really don't think there are any "structural" concerns. The roof skin isn't structural on these cars. There's a very thick structural skeleton that runs around the perimeter of the roof and down behind the C pillars, and you don't have nearly enough rust where I would be worried about any damage to those inner panels.


Jeff

 

[Just Carbs]

Considering the size of some of the holes, I think the best plan would be to use fiberglass cloth to cover them up. You can get a small kit at any auto parts store that will come with resin, hardener, and some cloth. This will give you the thinnest "covering" over the holes, and it's pretty sturdy once set up.

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As you said, you're looking to try to preserve things or at least slow down the rust process, and I think this is the most practical route. It won't last forever, and you'll likely need to touch things up every few years. No need to mess with the headliner, just do it all from outside. Grind out as much of the rust as you can and clean things up with the round wire wheels that you can chuck in a drill. I strongly recommend actually measuring the resin in ounces and stick with the 10 drops per ounce. It can be a bit poky to start setting up, but it will. Once the glass mat has hardened, you can sand it smooth and apply a coat of filler over top to blend the edges in with the surrounding metal. I did a similar repair on the doors of my old Ford dump truck 20 years ago and the repair hasn't reached a point yet where you would say that it's failed. It has some bubbling, but the rust hasn't poked through the glass mat yet.

Having much experience with these cars, I'd expect that you have quite a bit more rust hiding down in the window channels, and it would be a huge and expensive job to completely repair all the rust permanently. These days, it's close to impossible to find a professional shop that wants to get involved with this kind of job, so it's really up to you to decide what you can do to preserve it as long as you can. The best favor you could do for the car would be to get one of the metal, free standing carports to keep it out of the rain as much as possible. Unfortunately, fusey's are leakers, and it's really tough to keep the water out of them.

Jeff

RUST-OLEUM RUST DISSOLVER gel will eliminate all the rust.
It will also discolor the paint if it sits on the paint for more than 20 minuets. But it doesn't attack the metal at all from what I can tell from using it.
Cover the holes from the inside "really good" with metal tape, or whatever.
Brush it on "thick" with a soft pool table type brush, agitate it every few minutes, hose it off when it starts to dry up in about 30 minuets to an hour. It's easy to rinse off. Repeat till the rust is GONE.
Any nonvisible place it gets to is probably of no concern. Like under the windshield areas. It will dry to a harmless chalk powder.
Something inside the car is for sure going to get wet/soaked when doing the windshield and back glass. Lots of these cars have gotten wet under the dash a few times before leaks were detected and fixed without causing problems. Maybe a house dehumidifier in the car will dry it out fast enough.

Do that and then make with the fiberglass. I bet it's permanent.
It's a GEL and stays "mostly" where it brushed on.

The gallon is not a gel.

 

[Carmine]

Also, I really don't think there are any "structural" concerns. The roof skin isn't structural on these cars. There's a very thick structural skeleton that runs around the perimeter of the roof and down behind the C pillars, and you don't have nearly enough rust where I would be worried about any damage to those inner panels.


Jeff

I think this is the most realistic comment. That outer skin of sheet metal is not part of the car"s structure, although it doesn't hurt.

If it were me, I go after it with one of the rust removal ideas suggested so far, then from the back side I would install new sheet metal using panel bonding adhesive. Then I would probably use a fiberglass reinforced body filler to skim the low areas and pits. If cost is an issue, I would roll on some good old-fashioned oil based Rustoleum or Sherwin-Williams Machinery paint. Pick a color you can live with for probably 6 months to allow it to outgas. This will also allow you to see if any rust reappears. At that point install a new vinyl top if you are so inclined.

 

[Just Carbs]

Rust remover solution containment is a problem. It gets everywhere.
A few years ago, I mixed some fumed silica into some 40 percent phosphoric acid to make a stiff paste that stays put on the car inner fenders until its washed off. Worked good, but sold the car two years later and don't know the long game consequences.
I think it would work on the window mount channels.

 

[57fury440]

I think once you use the rust dissolver you might end up with a convertible. I would sand it with some rough sandpaper, then use a rust converter and go over it with fiberglass resin and cloth. Your roof is really porous, and you might end up with a real mess. I still think replacing the roof skin would be the best way. If you don't weld, then you could bond it on like they do with panels on the new cars.

 

[Just Carbs]

Don't know till the rust is gone.
My experience with rust is it gets gone or it don't.

 

[Wonderwagon]

Another option might be to sweat solder on metal patches from the inside. Then bondo and sand from the outside. Good base and maybe a longer term temporary solution

 

[TxDon]

Sorry for your pain, vinyl tops were one of the dumbest options ever offered. Have you removed the window trim yet? Doing that may solidify the choice of repairs, I have a hunch it will be worse underneath.