Driver's window: difficult down, easy up
 

Long time lurker just got my first 911, an 86 coupe.

The day the car arrived I was checking every thing out and found the driver side window went down but wouldn't come up. Took the door apart, turns out the motor is non-op, replace the motor put door back together and find it goes down vey slowly, seems like its struggling, but it goes up with no problem. Is this the window regulator?

See if it works better when you apply gentle pressure to the front or rear edge, the glass might be tilting in the frame on the way down. Strange though, usually a problem in the other direction when you are working against gravity.

It might be catching on the felt runners, check their condition.

new felt time.