Sunroof rust issue. Thoughts on how to repair? (1 Viewer)

[Red Merle]

Just when I thought I knew where all the rust was on my truck, I found something bad for the first time last week when I was applying that weird German goop that people recommended for conditioning rubber seals.

As far as I know, I don't have any issues with leaks getting into the roof and I don't get any water built up under the carpets. The drains have been cleared with a weed wacker string. The sunroof otherwise functions perfectly.

My concern is that if I try to remove the sunroof to install a new unit, I will mangle my perfect headliner(I have the lovely '94, which I am told is NOT easy to remove or reinstall). I am also concerned about getting a used one and not being able to get it all back together properly.

I am leaning towards just trying to get this cleaned up with a wire wheel and then treat with POR15 and then pumping some body filler into it and then painting it. My other idea would be to use a high quality paintable caulk like OSI Quad so that things can shrink and expand with temp changes.

I would prefer to avoid the classic Red Merle program of making little jobs into big jobs on this and I would be able to live with a repair if I thought it was going to work and not cause future issues. The hole is right above the driver's seat, which is why I never noticed it before. The hole is currently about the diameter of a dime, but I have a feeling it will expand quite a bit if I try to grind it out. It's not great, that is for sure and I really don't want to cause the sunroof to leak by futzing with this.

Any thoughts on what I should try to do here?

 

[baldilocks]

The photo is so close up its hard to tell exactly where this is.

 

[Red Merle]

The photo is so close up its hard to tell exactly where this is.

It's on the front of the sunroof on the driver's side. The map book above it is outside(I had to put something up there to get a "decent" photo.) The sunroof is open by about 5" in the pics.

 

[Malleus]

You do not want to remove this if you don't have to. There is no way to remove the headliner fabric without ruining it. Try to get at all the metal you can reach with a brush and remove the loose scale. Wipe it down with Ospho and let it sit, with the windows open (obviously indoors), overnight. Wipe off any remaining fluid residue. The Ospho will convert the iron oxide into iron phosphate, sealing the metal and preventing further oxidation. It'll be black when the iron oxide is converted (it will not be pretty). If the ambient temperature is below 50°, it may take two days. The reaction will slow down below that temperature. There is no need to paint anything you can't see, the iron phosphate is a permanent coating. It does serve as a primer prep, if you want to paint. It not only provides rust inhibition, but also serves to provide better adhesion for the primer than bare metal gives.

FWIW, this is why I mentioned in my earlier post that a rust inhibitor is always necessary before priming. It serves those two functions and both are necessary. Bare metal oxidizes almost immediately and if you don't do something about it, the paint coating lifetime will be less than optimal.

Also, if you can get it, zirconium phosphate is even better than Ospho. The largest US manufacturer is near you somewhere, IIRC.

 

[Red Merle]

You do not want to remove this if you don't have to. There is no way to remove the headliner fabric without ruining it. Try to get at all the metal you can reach with a brush and remove the loose scale. Wipe it down with Ospho and let it sit, with the windows open (obviously indoors), overnight. Wipe off any remaining fluid residue. The Ospho will convert the iron oxide into iron phosphate, sealing the metal and preventing further oxidation. It'll be black when the iron oxide is converted (it will not be pretty). If the ambient temperature is below 50°, it may take two days. The reaction will slow down below that temperature. There is no need to paint anything you can't see, the iron phosphate is a permanent coating. It does serve as a primer prep, if you want to paint. It not only provides rust inhibition, but also serves to provide better adhesion for the primer than bare metal gives.

FWIW, this is why I mentioned in my earlier post that a rust inhibitor is always necessary before priming. It serves those two functions and both are necessary. Bare metal oxidizes almost immediately and if you don't do something about it, the paint coating lifetime will be less than optimal.

Also, if you can get it, zirconium phosphate is even better than Ospho. The largest US manufacturer is near you somewhere, IIRC.

Thanks for the response. I agree that removing the sunroof is not really an option. As for the ospho, I wasn't really disagreeing with you, I just thought he had it down to bare metal and that not using it probably wouldn't have caused problems for him. That said, this is an entirely different situation and I know for sure I am not going to be able to get this really clean without damaging the seal. I have some Rust Mort Rust Mort™ | morttm | SEM Products. Do you think that will be OK?

What are your thoughts on the caulk vs. body filler idea? I could shoot some caulk in there and let it cure and then use the body filler. That way there would be a little flexible layer to account for expansion. I feel like I need to do something though or I might run into trouble with the metal frame becoming unstable.

 

[MoJ]

Remove the plastic trim on the sunroof. Remove three nuts each side. Pay attention to location of shims. Push the sunroof out the top of the vehicle. Replace sunroof with new one.

 

[MoJ]

Sunroof without trim

 

[Red Merle]

Remove the plastic trim on the sunroof. Remove three nuts each side. Pay attention to location of shims. Push the sunroof out the top of the vehicle. Replace sunroof with new one.

Do you need to do anything with the headliner if you do that?

 

[Malleus]

I haven't done this on my '94, but when I tried I stopped about two minutes into the process. It's easily doable on the later models; the headliner drops out of the way, since it's glued to the cards and not the roof.

 

[Malleus]

Is your problem the roof or the sunroof cover panel?

 

[Red Merle]

I haven't done this on my '94, but when I tried I stopped about two minutes into the process. It's easily doable on the later models; the headliner drops out of the way, since it's glued to the cards and not the roof.

The FSM talks about needing to lower the headliner in the front and removing the gear drive assembly, but then it goes on to say that you can remove the trim pieces and pull the glass. It's unclear if the earlier steps were to prepare for full removal of the whole assembly, or if the glass and frame could be pulled out without doing those first steps.

 

[Red Merle]

Is your problem the roof or the sunroof cover panel?

It's the frame that holds the glass panel. There is a used one on eBay right now that looks pretty good that I would buy if I could do this without getting into the headliner.

 

[MoJ]

Careful buying a used one. If the seal is dried out it will allow in more water than the drains can keep up with.

 

[Red Merle]

Careful buying a used one. If the seal is dried out it will allow in more water than the drains can keep up with.

I thought about that. I just bought it though. It was only $100 shipped, so if it doesn't work, I won't be out too much and I will have to pony up for a new one which will be more like $400. Maybe I can pull the seal off of mine and put it on the used one if it looks bad.

 

[MoJ]

I don’t think you’ll be able to swap the seals. Here’s a better reference for the location of the threaded studs. I haven’t removed one from a pre-95 but I’m pretty dang certain it’s got nothing to do with the headliner. Just go pop off one of the plastic trim pieces and have a look

 

[Red Merle]

I don’t think you’ll be able to swap the seals. Here’s a better reference for the location of the threaded studs. I haven’t removed one from a pre-95 but I’m pretty dang certain it’s got nothing to do with the headliner.

View attachment 1651519

Yeah, I am just going to hope the used one doesn't leak too bad in my truck. Otherwise I will just put my old one back in and wait until I can afford a new one.

I took the trim pieces off like you mentioned and it sure does look like I can just loosen the nuts and lift the old one out. Thanks for the response. I didn't think this would be an option, but now that it seems like it is, I would rather just get one in that doesn't have the rust hole.

 

[MoJ]

It really is a shame the seals can’t be replaced. I had to buy a new panel because the seal was toast. They’re spendy.

 

[Red Merle]

It really is a shame the seals can’t be replaced. I had to buy a new panel because the seal was toast. They’re spendy.

I hear ya'. So why can't you pull the seal off and use it over? Is it all glued on there or pinched into the steel somehow?

 

[MoJ]

It’s bonded to the glass very well. Removing the seal would most likely destroy it and there’s no replacement available. Perhaps there’s something from another vehicle that would work but I couldn’t find it. I did note the seal on the new panel was an updated design

 

[Malleus]

These sunroofs are delivered to Toyota as a unit, with the seal permanently installed. Unlike the 100s and 200s, which have $30 replacement seals, you have no option other than to buy the replacement glass. Yes, for $400, if you can find them for that.

You and I know what the problem is; someone with a later model can't appreciate what a PITA the glued on fabric is. The glass is the only sealed component you have to worry about. Everything else you can take care of when you swap the glass. The pan seal is another story; I don't see how that would be easy to get at. I think you can get the glass out of the early models without mangling the headliner fabric, but not the pan. Someone who's done it before would be a better resource than me. @cruiserdan probably knows.

I agree I'd stay away from used glass, even if it's "verified" leakfree, when it was removed. The seal's 20+ years old. Read my earlier posts on the sunroof drain subject; @MoJ, post #10, is correct, the dust seal on the glass does tend to regulate the ingress of water, but it doesn't seal it out at all. The drains were intended to carry the water away from the interior. If you've a rust problem, I doubt it's a clogged drain tube, although it's not impossible. More than likely it's a dirty rocker panel void. The pinch drains get plugged and the water backs up, into the floorboard and the sunroof tray/pan/frame (whatever we're calling that these days; Mr. T calls it the housing assy)