Probably beating a dead horse but I just bought a D1 with really low miles on it and I want to use the sunroofs on it. They dont leak at all but the front one will only pop up and the passenger side rail will only want to retract. The rear one pops and retracts fine. I think the sunroofs are a pretty cool feature and want to keep them working. However, my old D1 didnt have sun roofs and I have zero experience working on them and from what ive found on here has to only deal with leaks and completely non functioning sun roofs. Just wondering if theres some plastic gears in there or something that may have broken but I cant find anything broken or wrong with it.

 

I don't have experience with this personally, but I've heard there are little plastic bearings within the tracks that dry up and desintegrate. Might want to start there, look for anything visually different between the two rails. Look for corrosion, that one rail may be seized. Also, it's a bit of a pain, but I'm pretty sure removing your headliner will greatly ease your maintenance on either sunroof.