I recently purchased a 1983 320i and the manually operated window comes off track and gets jammed when rolling it up. I've looked on-line for a descriptive video; however, I can only find those for E46 and E39. There is nothing specific to the E21. I've looked at the RealOEM exploded diagram, and although it is helpful it doesn't really out line a procedure. I'm waiting for the E21 shop manual to arrive, but you never know how helpful that will be to the uninitiated. Suggestions, comments, recommendations?