Leaking Sunroof Repair

[ronmanfredi]

We recently discovered that the sunroof in our 82 Avanti was leaking water and we could see that the glass was sitting below the roof skin on its back side.  Upon further inspection, it was discovered that the sunroof frame had separated from the roof skin on the back side and partially on the passenger’s side.  I read the “repairing a sunroof” article on the Bob Jonestone’s website to get an idea of the repair process.  I also inspected the 2 rear sunroof frame mounts close to the rear glass and they were still in good shape, so I didn’t have to remove the head liner to fix those.

To start, I removed the sunroof glass and interior trim panel and then covered the hole with thick paper to protect the cars interior.  I removed the weather strip and then took 35 grit sand paper and roughed up the separated areas on both sides.  Next, I took some 1/4” high quality plywood and made a clamping plate to use with the clamps that I had to clamp the sunroof frame back up to the roof skin.  I covered the body painted area with tape and then did a test clamp to be sure that the entire roof skin would make contact with the sunroof frame.  I marked the clamp locations, removed the clamps, plate and proceeded to fill the gaps with epoxy.  I used the JB-Weld epoxy for fiberglass and metal that comes with its own 3” long mixing nozzle.  This eliminated me having to mix up the epoxy and made injecting it into the gap really easy.  Once I had all the epoxy injected, I reinstalled the plywood clamping plate and clamps.  Lastly, I wiped off the epoxy that oozed out around the edges and let it sit overnight.

The next day I removed the clamps and everything looked really good, so it was time to work on reinstalling the weather stripping.  The old weather strip on the body and the glass was all bad, so I contacted Dan at Nostalgic Motors to purchase new stripping.  The original weather strip in no longer available, so Dan furnishes the felt piece that contacts the sunroof frame and you have to locate and install the rubber strip that fits behind it and into the roof body section.  I found that a ½” wide by 3/8” deep high density foam rubber weather strip off Amazon was the way to go.  After removing all of the old weather strip and rubber shims behind it on the sides, I discovered that the depth for the new weather strip was correct except for the 2 front corners.  They were a little deeper, so I used 3M trim tape as a shim to bring the rubber weather strip flush with the body on the front and sides.  The next part is to glue the Felt weather strip piece that Dan supplied to the foam weather strip, using 3M Black weather strip adhesive.  Once done, the sunroof would fit correctly.  The back side of the sunroof glass has a piece of weather strip that attaches to it as well, which requires some detailed trimming and installation as shown on Bobs website article.

With the weather stripping now complete I installed the interior panel, the sunroof, adjusted the sunroof slide stop so it closed correctly and the repair was now complete. The sunroof now opens and closes as it should and I don’t have any water leaks into the interior.

 

[Zedman]

Thanks for this article, Ronmanfredi. I have a sunroof that I believe may have to come out come out because I've managed to fish some rusted scraps of mild steel out of there.  Anything that serves to inform future practice is welcome ! Any chance you could supply the URL for the Rubber strip for perusal ?

To be honest I'm hoping somebody out there can supply some advice on peeling back the headlining...

Edited October 25, 2023 by Zedman

[Bill Hanlon]

When addressing the same issue on my 1983 the original issue was the passenger side rear corner. As I clamped the original fix the stress caused the driver side front corner to start to fail.   I ended up re doing the whole top on two steps. 
 

instead of using the JB weld I used 3M panel epoxy longer applicator/injector. It has been 5 years and all is good. 

[ronmanfredi]

6 hours ago, Zedman said:

Thanks for this article, Ronmanfredi. I have a sunroof that I believe may have to come out come out because I've managed to fish some rusted scraps of mild steel out of there.  Anything that serves to inform future practice is welcome ! Any chance you could supply the URL for the Rubber strip for perusal ?

To be honest I'm hoping somebody out there can supply some advice on peeling back the headlining...

Here you go:  https://www.amazon.com/dp/B0BTNRTTFL?ref=ppx_yo2ov_dt_b_product_details&th=1

 

[ronmanfredi]

29 minutes ago, Bill Hanlon said:

When addressing the same issue on my 1983 the original issue was the passenger side rear corner. As I clamped the original fix the stress caused the driver side front corner to start to fail.   I ended up re doing the whole top on two steps. 
 

instead of using the JB weld I used 3M panel epoxy longer applicator/injector. It has been 5 years and all is good. 

 

 

I'm guessing each one of these repairs are going to be different depending on the amount of damage they have.  I looked at the 3M panel epoxy with the gun and almost spent the money on it when I discovered the correct epoxy from JB for way less.  

[mfg]

MORE POWER to you talented Avanti owners!!.....

I wasn't so brave.....

Got fed up with the moonroof leaks on my '83, and closed roof opening in with a sheet of virgin 1/8" fiberglass.....

Had to bodywork and refinish roof..BUT I FIXED THE LEAK!!!

 

 

[Footer]

Pictures in Bob Johnstone’s Avanti registry show my 83 with a moonroof, but somewhere along the line it was removed, possibly by previous owner Mike Valent of Florida. He has passed and I haven’t been able to find any history on the car, but whoever did the work did a very good job. I think Nostalgic still has roof skins available, but then there is the headliner to contend with.  Mike

[Geoff]

So um, wowzers! What a week it has been here. Sheeeeesh!

Anyway, I've had some thoughts on my current project. In no particular order:

• Fix what's in the car. Articles like these are helpful.
• "Simplify and add lightness." -Colin Chapman.
  • Remove sunroof and offload to someone who could use it. Plus, less weight and less weight up high. Double bonus.
  • Maybe remove and replace with a rudimentary moonroof (lift and latch rear for vent / pop out and stow the panel).
• Uninstall the current inbuilt moonroof and replace it with a spoiler moonroof.

The idea of using a spoiler moonroof would be to reduce the size of the storage box inside the car. Spoiler moonroofs are the ones that slide rearward, outside. That's a re-engineering issue though because I have to find a spoiler roof I like and adapt it to the car. My measurements of the car's current hole are ≈35.5" wide ≈17" long. If I was to do this I am comfortable altering each dimension. I have also thought of getting a longer moonroof, with panoramic plexiglass extending rearward of the roll bar hoop.