'89 200Q stuck rear power windows.

[LL - NY]

Brett, you were dead on, motors frozen, power was there at the motors. But
the buyer was willing to take the car AS IS now that I had done all of the
diagnosis. So, no, I didn't do the motor rebuilds, but I was trying to avoid
disassembly of the door to check all the way to the motors. Thanks for you
help.

LL - NY

On 4/30/06, Brett Dikeman <quattro at frank.mercea.net> wrote:
>
>
> On Apr 30, 2006, at 9:27 PM, LL - NY wrote:
>
> > Trying to diagnose WHY my rear windows won't work on an '89 200Q. I AM
> > getting power to the rear window switches. Safety switch seems to be
> > working properly, the rear window switches light turns on and off in
> > conjunction with the safety switch. Depressing a switch in either
> > direction does cause the dome lights to dim. (One thing of note is the
> > rear ciggy lighter doesn't work, and from the wiring diagram, they
> > seem to be linked in a series.) I checked voltage at the switch and it
> > appears that all is in order.
> >
> > Has anyone ever had a window that just got physically stuck and it
> > simply needed a boost (while the electricals were working "properly"?
> > I haven't tried directly jumpering the motor wires (just to verify,
> > which two are they?) to a 12V source, it was getting late. Any
> > suggestions?
>
> I had a similar problem with my 200q20v when I put it back on the
> road after 6-9 months of not driving it; the switches clearly worked,
> as pressing any of them in any direction caused a big current draw.
> I finally got around to fixing it recently.  Loosening the screws
> that hold the motor case on, I could feel it twitch a bit when I
> cycled power, but nothing more.  I ripped it apart and found one of
> the commutator contacts has a nice big discolored spot on it, the
> sintered bearing had rusted up a fair bit, etc.  Lots of life left on
> the brushes, however.
>
> I removed the regulator gearbox+motor (zip tied the spool to keep it
> intact) and went to town cleaning it up.  A cordless drill is perfect
> for "turning" the rotor to polish the shaft and commutator; a long q-
> tip on a dremel works well at cleaning up rust on the sintered
> bearing.  I use 3M marine metal restorer; it has some sort of acid
> and an aggressive compound that puts an almost mirror-finish on stuff
> effortlessly.  I used 500 or 600 grit paper to even out the
> commutator contacts, cleaned the built-up carbon from between the
> channels with a razor blade, etc...re-greased the gearbox with M1
> synthetic bearing grease, etc. I also stuffed a fair bit of grease
> into the bearing area in the motor case, applied a bit of Boeshield
> to the magnets+rotor etc to keep them from rusting up, and so on.
>
> Works wonderfully.
>
> Oh- the tricky part is getting the brush assembly out, especially if
> the case has corroded somewhat.  If it won't come out easily, apply
> some PB blaster liberally and come back in an hour and try again.  If
> you tug on the white part too hard, you risk ripping various bits off
> the -black- half underneath.  I did a little damage since I rushed
> it, and had to carefully push some wires back into place and re-
> solder connections.
>
> As a physics teacher, you'll appreciate the best method of getting
> the internals out once PB blaster has been applied- tap the motor
> case's tab against somehting like a bench vise.  Viola, everything
> inside slowly pops out.  Just watch that you don't mangle the brushes
> too badly.
>
> Brett
>
>