Roofy

[BristolE30]

too may keyboard warriors on here who earn there living by sitting at a desk all day not repairing cars.

/\/\/\/\/\/\ this,
there's far to many on hee who would scrap that soon as they saw it,
find a proper competent bodyshop & they'll have that done pretty quick.

I hope that was not aimed at me, spent more than a few years spannering and panel-beating, brought many a car back from the dead undoing quite a few bodge jobs as I went. However (for better or worse) I only do things one way

Bmw, in their wisdom, did not bother to paint in there.

Not painted as such but it looks like a bare e-coat which is now at the end of its life. Unless this is protected the rust will now just keep coming back.

You need to kill the rust between the roof skin and the cassette/frame. Especially where the mastic bonding the sunroof onto the roofskin has shrunk leaving uncoated metal. If the e-coat has given up you need to paint it like BMW should have done in the first place. No easy way to do that with the sunroof cassette in the way.

I had my own opinion about the right way to do this to one of mine, speaking to a couple of bodyshops that do E30s (including the one that did BMR Barry’s M3) it seems I was probably optimistic.

You can patch it up, fill it and how long it will last will depend on how well you have killed the rust and protected underside of the repair. However next time you see rust there it is likely to be a much bigger problem needing roof panel, cassette and inner roof frame sections.

Sorted properly now it will be good for another 30 years

Many are dropping the sunroof cassette in good cars just to do this. Seen this being done, not that big a job really.

It all depends on what you want to do with the car, how long you are keeping it. But once rust has come through don’t be fooled into thinking it is an easy fix for the long term. A lot of the protection on these cars has reached end of life and needs renewing.

Ironically my henna chromie, 5 years older, seems to be much better protected.

Anything you recommend me saying to the body shop to have a go at?

[BristolE30]

Not painted as such but it looks like a bare e-coat which is now at the end of its life. Unless this is protected the rust will now just keep coming back.

You need to kill the rust between the roof skin and the cassette/frame. Especially where the mastic bonding the sunroof onto the roofskin has shrunk leaving uncoated metal. If the e-coat has given up you need to paint it like BMW should have done in the first place. No easy way to do that with the sunroof cassette in the way.

I had my own opinion about the right way to do this to one of mine, speaking to a couple of bodyshops that do E30s (including the one that did BMR Barry’s M3) it seems I was probably optimistic.

You can patch it up, fill it and how long it will last will depend on how well you have killed the rust and protected underside of the repair. However next time you see rust there it is likely to be a much bigger problem needing roof panel, cassette and inner roof frame sections.

Sorted properly now it will be good for another 30 years

Many are dropping the sunroof cassette in good cars just to do this. Seen this being done, not that big a job really.

It all depends on what you want to do with the car, how long you are keeping it. But once rust has come through don’t be fooled into thinking it is an easy fix for the long term. A lot of the protection on these cars has reached end of life and needs renewing.

Ironically my henna chromie, 5 years older, seems to be much better protected.

Anything you recommend me to ask the body shop to have a go at to reduce the chance of rust coming back?

[flybynite]

Anything you recommend me to ask the body shop to have a go at to reduce the chance of rust coming back?

Common sense really, from the hole they have cut, feel round underneath, inside the roof. Make sure the rust underneath (always more extensive) has been cut out or rubbed well back and treated. Spray weld-through primer in the hole and on the back of the replacement metal

When it is done blast good waxoyl (warmed as opposed to thinned to loosen it up) using a fine tube as close as you can get to the area. Get it behind any area you can. It may be easier to remove the sunroof panel to get access .

[Steve]

@BristolE30

Hi mate, I got your email, I’m trying to reply but got a rubbish signal not sure if it’s sending.

Try this -

Try clearing you cookies, there is a link at the very bottom right hand corner of the forum that says ‘deleted cookies’ click on that then login again.

It should solve your problem.

[BristolE30]

She lives on. Got her back from the body shop and wow they’ve done a fantastic job! The work is totally unnoticeable and perfect. For anyone worried about their roof, don’t be. Just find a good body shop, get the rot cut out and replaced with fresh metal. Nothing more to it! Photos below of the steps.

The rust is cut out a little further to fresh metal

DFE4EF57-BFA9-4240-9EEA-6625D6E7C99C.jpeg

The area is cleaned up and sprayed with zinc primer and wax. New patch welded in

D30C4E49-8F75-4E66-9B3F-94937DA16828.jpeg

CCBAD13A-B9A0-4A34-B6F4-A3CF23DE7C98.jpeg

E15DE738-4E84-4E52-90BB-C3BBE7FC5B5C.jpeg

The next step was to fibreglass coat, small layer of filler and respray roof. Headliner was also pulled back and wax sprayed inside frame and under weld to protect for future. Finished product:

[BristolE30]

E35C274D-7D09-4AFA-AEE4-A51BF8A9A008.jpeg

[flybynite]

Looks a good job and as I said above you should get some time out of it.

Not a criticism, more something for the future, if it has rusted there, it is an indication of problems further in.

If you read these pages, you can see the problem. It is the same as I have seen on the ones I have. They have taken the sunroof out to paint the roof.

viewtopic.php?f=112&t=266832&start=105

viewtopic.php?f=25&t=264564

It may be worth getting a torch and look back into the cassette, if you can see rust it may be worth blowing something into the cassette to slow it down. It is not too big a job to take out the sunroof panel.

[Foe]

Nice update and a good job too

[stmachreth]

I'm in a similar position with the Touring I just bought. There's a few small points of rust, nothing quite so concentrated as your bubbles (and mine look more like chips with surface rust but you never know).

I've decided to remove the cassette, treat and seal the roof and skin as best I can, and save the 15kg of mechanism. Might regret not having a sunroof but never as much as the pain of fixing a rotten roof.

[BristolE30]

I'm in a similar position with the Touring I just bought. There's a few small points of rust, nothing quite so concentrated as your bubbles (and mine look more like chips with surface rust but you never know).

I've decided to remove the cassette, treat and seal the roof and skin as best I can, and save the 15kg of mechanism. Might regret not having a sunroof but never as much as the pain of fixing a rotten roof.

Interesting. I’ve pondered doing this also, I barley use the thing. How did you about removing it?

Cheers

[flybynite]

Personal thing I know but I never drove the E30 without the roof tilted unless it was hammering with rain. It draws more air through the vents and heater and you can hear the exhaust better

If you are taking the cassette out to do the roof, best thing is to treat it all and paint it then put it back, should be good for another 30 years. Irony is it is not the sunroof causing the issue, but the fact they never painted the roof properly from the start.

Filling a sunroof to make it invisible and not leave a worse rust trap is a tricky job

I have both put sunroof cassettes in non sunroof cars and filled a few sunroof holes many moons ago (undoing at least one badly leaking attempt as I went) I never found a method I liked or completely trusted. My preference was always to put in a non-sunroof skin complete.

Most push a sheet up from the underneath after any returns are ground off, this is then welded in place and the whole thing covered in filler.

Instead of filling I used to cut a sheet 1mm short of the exact hole and pushing down onto the lower sheet tack it in place flush and braze to finish, One I did like that is still on the road couple of decades later. Properly dressing and sealing the underside is key.

Best one I saw was the roofskin return around the sunroof joggled to a recessed flange to take a perfectly cut panel domed correctly on a wheeling machine then tacked to the flange from below and brazed to seal all without warping the roof. It was a work of art and the beauty of it was the roof could be put back in the future. Beyond my skillset both then and now.

[stmachreth]

BristolE30,
I haven't done it yet. There are several decent-looking sets of instructions to be found on the net, the one on this site one of the better ones I think.

flybynite (hope that's a Rush reference) , you make a great case for reinstalling the cassette after sorting any rust. Could also then refit the same headliner.