Now picture this: It's a wonderful sunny day with mild temperatures, your love interest is quietly sitting beside you as you're cruising on a later Sunday afternoon drive into the country. Nothing could be better until you lean forward to pull the sunroof switch and NOTHING. Or worse ... POING! (It's the worst possible sound a sunroof makes!)
Stop! Do not open or close the roof. The most common cause of a sunroof jamming is maintenance, of lack there of. Usually the tracks are clogged with dirt or hardened axle grease (as was the case with my 1963). When this problem gets too bad and the sunroof is forced open or closed, the worse problem happens, cable breakage!
If the cables have not broken, there is an easy fix. First cover the interior with a drop cloth because working on the roof will get messy. Allow room to get inside under the opening of the sunroof. Without moving the roof, spray some Jet-Spray carburetor cleaner on, in, down, and under the track. Be careful not to get any on the paint. Also spray in the groove of the sunroof roof.
Next, take a Phillips screwdriver and remove the two screws that are at the front edge of the sliding roof on the inside of the car. The headliner on the sliding roof is stretched around a frame that is held by the two screws. Grab the frame and gently pull forward ON THE FRAME AND HEADLINER ONLY! The sliding roof should remain still.
When it is loose, push the headliner to the back until you can see the underside of the sliding roof. Just under the sliding roof to the left and on the right you will be able to see the cable that pulls to sliding roof. Clean it with the spray, then lube it, preferable with a Teflon spray grease (like White Lithium Grease). It's messy but it works great! Lube the rest of the track, and try the switch again. If it doesn't work, clean it again. You may need to clean it over again after the sliding roof starts to move.
Finally, replace the headliner and your work is done.