Tips On Replacing A Roof

[Mucci]

The bad news is I found out my roof has some pretty aggressive rust on the underside that's starting to bubble to the top. The good news is I'm already stripping the car down for paint. 

 

I'm a fabricator but most of my experience pertains to motorcycles so I'm looking for tips on replacing the roof in the car with one from a donor. 

 

With the little bit of research I've done it looks like a common way to replace a roof is to tack in a trusswork of angle iron on the interior that ties the lower pillars to the body and each other. Then chop the pillars like halfway up. The trusswork is to keep the lower pillars in place after the roof is gone. Measure and chop out the donor roof in the same spot then weld it to the lower pillars stubs of the main car. 

 

This seems like a good tactic in theory since I imagine the cross section of the pillars prevents warpage when welding. 

 

I'm interested in hearing from others who might have tackled this already. Have any tips or feedback?

[Conserv]

By “aggressive rust”, I’m guessing that you mean rust has materially damaged structural elements of the roof, and not simply the skin. 

 

I mention this only because there are two ways to add/subtract a factory sunroof to/from an ‘02. One method is as you describe above. The other method is a transfer of the roof skin, as described in the following article:

 

 

Again, the skin transfer method is not applicable if your roof’s structure is inadequate to support it!

 

Regards,

 

Steve

 

[Mucci]

Although it does appear to be mostly just the skin that's affected, chopping the full roof at the pillars seems way easier. Having to drill out and reweld a million spot welds then grind them all smooth looks like a real pain in the ass. What's the benefit to doing that? 

 

I just saw some neat structural tips in a YouTube video where the guy sliced the outer pillar skin at one spot then the inner about 4" lower. He did the inverse to the donor car that way your weld seams aren't on the same plane. He also made a sleeve that fit inside the pillars and welded through to it a couple inches above and below the main weld. Thought that was neat. 

 

Here's my infection. The driver's side inner structure looks good but the passenger side is rusty. I wonder if the drip rail was clogged up over there. Or maybe a bad seal?

 

 

 

 

 

 

Edited July 30, 2019 by Mucci

[Son of Marty]

If your donor roof has a sunroof be careful adding reinforcement in the A pillar as the sunroof drains need to go down the pillar and there's not much room to do it. 

[Mucci]

6 minutes ago, Son of Marty said:

If your donor roof has a sunroof be careful adding reinforcement in the A pillar as the sunroof drains need to go down the pillar and there's not much room to do it. 

 

Ah yes, good point

[Conserv]

1 hour ago, Mucci said:

Although it does appear to be mostly just the skin that's affected, chopping the full roof at the pillars seems way easier. Having to drill out and reweld a million spot welds then grind them all smooth looks like a real pain in the ass. What's the benefit to doing that? 

 

I just saw some neat structural tips in a YouTube video where the guy sliced the outer pillar skin at one spot then the inner about 4" lower. He did the inverse to the donor car that way your weld seams aren't on the same plane. He also made a sleeve that fit inside the pillars and welded through to it a couple inches above and below the main weld. Thought that was neat. 

 

Here's my infection. The driver's side inner structure looks good but the passenger side is rusty. I wonder if the drip rail was clogged up over there. Or maybe a bad seal?

 

 

 

 

 

 

 

I suspect the benefit of the re-skin method is that you don’t alter the structure of the vehicle or have to worry about alignment. From what I’ve heard, it’s more expensive, so presumably more time-intensive.

 

I wonder if your car had one or more plugged sunroof drains and thus accumulated water in the sunroof tracks and roof reinforcements.

 

Is that Taiga metallic paint, or Mintgrun paint? Either way: two desirable colors!

 

Regards,

 

Steve

 

Edited July 30, 2019 by Conserv

[Mucci]

29 minutes ago, Conserv said:

 

I suspect the benefit of the re-skin method is that you don’t alter the structure of the vehicle or have to worry about alignment. From what I’ve heard, it’s more expensive, so presumably more time-intensive.

 

I wonder if your car had one or more plugged sunroof drains and thus accumulated water in the sunroof tracks and roof reinforcements.

 

Is that Taiga metallic paint, or Mintgrun paint? Either way: two desirable colors!

 

Regards,

 

Steve

 

 

I was thinking the same thing. I bought it as an ugly runner that someone definitely dumped a bottle of bleach into - I had assumed due to some sort of water leak / mold issue. This pretty much confirms that.

 

What once was Taiga shall return to Taiga! On top of aerosol flat blacking the exterior the previous owner also reupholstered the interior bright red and bondo'd up all the trim holes. There will be much restoration in this project...

[npdw]

Why don't you chemically dip your car so you get rid of all the rust? Only applicable if the structure is good enough. Saves a lot of trouble. 

[Conserv]

33 minutes ago, Mucci said:

 

I was thinking the same thing. I bought it as an ugly runner that someone definitely dumped a bottle of bleach into - I had assumed due to some sort of water leak / mold issue. This pretty much confirms that.

 

What once was Taiga shall return to Taiga! On top of aerosol flat blacking the exterior the previous owner also reupholstered the interior bright red and bondo'd up all the trim holes. There will be much restoration in this project...

 

Go, Taiga! Great color.

 

And Taiga is rarer than Mintgrun!

 

I see the pinholes and likely more would appear if you bead-blasted or soda-blasted the entire roof structure. But... I’m curious whether your car’s roof rust issues could be more easily solved with a few patches properly welded in, rather than with a full roof replacement. As a fabricator, I realize you could probably do a roof swap fairly easily. But do you really need a new roof?

 

Not trying to dissuade you from a roof replacement, but maybe — maybe — less would solve the problem.

 

Regards,

 

Steve

 

 

[Mike Self]

I did a column on determining the cause and then repairing a sunroof roof with the same problem as yours--without having to weld.  PM me and I'll send you a copy--might save you some time...

 

mike

[ray_]

You might call Matt at Sports Car Restoration in CT. He used to have pics of the procedure he used on his website,but it seems not very organized there now.

 

Cheers,