I'm a long time lurker here and long time Corrado owner on and off for the last 15 years.
I've just completed the repair of my Storm sunroof and wanted to share my experience for the benefit of all.
I hope I'm not repeating the posts of others as even after scouring this forum for info, some of this was a surprise to me.
Firstly, fitting a Mk3 Golf sunroof:
Mine was from a late Mk3 (1997) and the mechanism fitted my late Corrado just fine and used the same motor.
However the fit of the glass panel was nowhere near right, there were gaps front and back so wind noise was terrible however I adjusted it and as mentioned in other posts, its convex so sticks up on the middle. Somebody posted how you could press down on the corners to reshape it but being glass I was suspicious and I couldn't see a difference even after jumping up and down on it as if it was a skateboard.
You can of course fit your Corrado's metal panel and from the outside this will look OK but the blind on the Mk3 is completely different and needs to be slid around by hand (unless you are sliding the roof back when it will slide back with the sunroof panel) and it doesn't tilt with the sunroof panel because it's not actually attached to it.
Somebody posted how you could bond the original Corrado blind to the sunroof panel to get it to open and close when tilting automatically but the problem with this is that when the roof is closed, the blind is still an inch or so open as the sunroof panel is only in its lowest position when it's dropped down under the roof skin.
So while the Mk3 roof is more reliable and is better than a broken roof, I felt it devalued my Storm and began the search for a good working Corrado roof which I picked up on Monday from a fellow forum member.
He demonstrated it working using the allen key method and it looked fine although there were some ominous cracking noises as he did it.
When I got it back I checked it over and found the rubber o-ring on the nearside locking segment (aka spring loaded slider) had worn so when opening the roof the two alloy pieces collided rather than fitting together. I replaced the o-rings with plastic vacuum pipe (I think it was old central locking pipe) trimmed to a couple of mm thick which worked a treat when I tested it using the allen key.
I removed the headlining and Mk3 roof and fitted the used Corrado roof in place and left out the blind but put on the sunroof panel and then tested it using the motor.
I couldn't believe it but as soon as the roof started to come forward to close, the sunroof panel was being forced into the roof skin! Luckily I hasn't had this repainted yet since it was damaged from by the old roof. It's possible I didn't notice what was happening before as I hadn't tested it with a panel fitted.
I took the panel off and carefully compared the good offside with the bad nearside and worked out that there was too much play in the nearside locking segment so instead of pushing the roof mounting frame forward, that was staying in place and it was instead pushing the roof upwards into the roof skin.
I googled the problem and eventually found this excellent page below where someone else was having the same issue and explained how the problem was caused by the mountings of the locking segment breaking.
He didn't give a part number so I used VAGCAT and it came up with
repair kit for water guide plate / for steel sliding roof
left rear /
repair kit for water guide plate / for steel sliding roof
right rear /
I quickly rang VW who said they had 1 of each available to order at around £70 each, in desperation I said yes, put the phone down and had a brainwave. 1H0 is a Mk3 Golf part number so I quickly checked VAGCAT to see if they were the same on a late Mk3 sunroof which indeed they were! I had a quick look at them on the mk3 Golf mechanism I'd discarded earlier and they were identical different only by being black rather than the cheap cast look of the originals.
It's childsplay to remove them and fit them to the Corrado mechanism, once done I tested using then Allen key method and all good.
(yes I did call VW and cancel my order!)
Another tip is to treat the blind with the utmost care. It's attached to the mechanism by two little arms which are what run up and down a groove on the top of the blind and move it when in tilt mode. These are VERY fragile and care needs to be taken when removing the blind for whatever reason. I found the safest method is to have the roof in full tilt mode and carefully push the blind towards the back of the car by pressing on the blind on the edge that is now available because the inner section has been raised (I can't see why VW made a special tool for this that Edd China used). Dont push too hard as the raised piece of blind will hit the roof skin when it releases. Then very carefully make the blind flat (i.e not in tilt mode) and keeping it in position in the tracks of the mechanism, slide it out of the way. To refit, with the roof still in full tilt but sunroof panel not in place, if the blind isn't already in the mechanism you can slot the blind in from the top (I do it this way as means the mechanism is lighter when offered up to the car and prevents the blind getting dirty/damaged), it's tight but it will go in , then (usually once you've fitted and adjusted your sunroof panel) you just need to guide the blind gently towards the front of the car by sliding it along the tracks, no need to raise it manually into tilt mode as when it mates with those fragile arms it will start to raise by itself. When nearly all the way forward you will need to apply some more effort so the spring clips on the blind mate with the rubber coated prong mounting on the mechanism. It is essential this connection is secure as if not, the blind will detach from the mechanism when the roof is being closed and guess what? Yep those flimsy cast arms break off. How do I know? Yep, it happened to me but luckily my old Corrado roof failed in the same way but on the other side so yes I had to strip it all down again and swap the bits over.
I had tested it thoroughly but got caught out as when I put the headliner seal in place, it increased the resistance of the blind as it moved along the track and it stopped in around the half way open position while the rest of the mechanism continued towards fully closed.
It's best to practice refitting and removing the blind a few times before you put the sunroof panel in place as it will be the last thing you do once you've tweaked the sunroof panel's adjustment.
A final tip is if the rubber cover has worn on the prong where the blind clips onto the mechanism, heat shrink does a great job of replicating it.
I hope this helps someone out there!