Many of the early ('91, '92) SLs that I've seen have power windows that move exceptionally slowly when activated, as though something is binding internally. Inspection of the window lift mechanism and motor reveals no gross faults. Repositioning the window panel laterally away from the guide seals appears to help slightly but also increases the occurrence of leaks during foul weather. Is there a known remedy for this fault? TIA.

I noted that on every 129 I worked on and never got a clear explanation of it.I guess the guy who designed it thaught it was ok...If it ain't broke...don't fix it!!!