240D (W123) electric sunroof problem

[ncarter]

The sunroof in my '83 240D has not been working for some time. The motor
works but the sunroof does not move like it should. When it first started
having problems, it would open fine but would not close by itself. To
close it required two people: one to push the button, and another to shove
the sunroof forward Now, it doesn't even open when I push the button.
The motor runs but the sunroof does not move properly.

My uncle (who was the original purchaser of this car) suggested that the
cable drive at the motor just needs adjustment, to make the motor "grip"
the cable a little better. I haven't dug around in there yet, but does
this sound reasonable?

Also, what points in the sunroof's sliding rails should be lubricated? How
often, and with what? I'd prefer it if this didn't happen again after I
fix it.

I suspect that an improperly-closed sunroof is the source of the water
leaking into my left rear floorboard.

Thanks.

- Nathan
'83 240D, 250k miles