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By Addlight
#77146
Edit: I'll leave the thread here, but turns out it was the motor.

I'll start with the question: I put new felt window guides in my driver door. Shortly after, the window stopped going up or down. Could new guides be installed tight enough to stop the window motor.

Long version:

I had the pleasure of taking my driver side door apart today to see why the window is not going up or down. Twice.

The switch worked, the motor was getting power, but it wasn't going up or down. I disassembled the motor, cleaned it, greased the bearings, reassembled. Bench tested and it ran smoothly. I reassembled everything, and when I did, I bolted the regulator to the door with one bolt, then ran the motor to align the other three bolt holes with the window held up by tape. Motor worked fine through the switch.

I put the door back together, including gluing in new vapor barrier. That's when I saw that the grease seal that goes between the window motor and transmission had fallen out and was hiding on my black carpet. So, repeat the entire process.

Got it buttoned up, motor worked fine when not driving window up and down, but now does not. I can't even hear it try to move when I use the switch.

Last thing I did to that prior to today was the felt guides. Could these be the problem? Should I go back in and see if I can back them up a bit?

Thanks,
Matt
Last edited by Addlight on Sun May 02, 2021 1:56 pm, edited 1 time in total.
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By Schocki
#77157
Did you replace the felt guides with new Porsche parts? They are a lot thicker and could be your problem already.
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By Addlight
#77166
I replaced with good used (928intl.com). They were definitely thicker than my worn out ones, I would say almost new. And they felt quite tight against the glass after installation. The window did go up and right after the replacement, though.

A few other things I will check: make sure the connector didn't disengage from the window motor when I put the door back together. I also tried the switch at various door openings to see if there was a wire break that was intermittent.

Matt
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By MFranke
#77204
The motor should still make a start sound if resistance. Suggest checking the power at the plug to the motor and the connection. and take care how you route the harness so the window doesn't pull on it. If you have power at the plug, but it doesn't move or make any sound at all, suggest open the motor again and check the thermal fuse.
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By Addlight
#77303
Update: it was indeed the motor. Pulled it and bench tested it, and nothing. Confirmed power at the door.

I was able to pull the brushes and armature from a spare motor I had (bushings and armatures are interchangeable driver to passenger, only the housing and transmission are different. I swapped the spares into the driver door housing, installed, and the window is back to operational.

You can buy a brand new brush assembly on eBay for about $25, and rebuilt motors on RockAuto for $80, but the rebuilds are Cardone, which tend to be crappy rebuilds. Also, our motors directly interchange with Saab 900s of the same generation. They are identical, but way, way cheaper used when listed as Saab parts.

I have to say, after three journeys through my door this weekend, I have it down to about a 60 minute process. I hope I forget everything I learned by the time I have to do it again.

Matt
Last edited by Addlight on Sun May 02, 2021 9:58 pm, edited 2 times in total.
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By Gary Knox
#77325
Matt,

Do the Saab motors for their left door (F and or R) function for the 928 S4 and later left door?

Thanks for the tip.

Gary
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By Addlight
#77329
Hi Gary,
I have an 86 so can't say for sure on the S4 and later, but the interchange says the same motor is used on 928s from 1984 through 1995.

Matt
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By Gary Knox
#77430
Matt,

I shouldn't have specified 'S4 and later'. My real interest is in regard to the left SAAB door for the left 928 door. I want to buy a spare motor, but be sure I get one that fits the left door.

THANKS,

Gary
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By worf
#77486
Gary Knox wrote: Mon May 03, 2021 8:22 am I shouldn't have specified 'S4 and later'. My real interest is in regard to the left SAAB door for the left 928 door. I want to buy a spare motor, but be sure I get one that fits the left door.
Interesting. After sowing your wild automotive oats you’re coming home?
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By Gary Knox
#77505
David,

All the oats are doing just fine, some wild, one not so wild. Just adopted one that is due for delivery from CA on Saturday. Thought a 'dentist's wife's car might fit right in the middle of those other oats!

And, any car that qualifies as an 'antique' for PA registration (and every 928 qualifies) will eventually need a left door motor!

Gary
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By Addlight
#77548
Gary Knox wrote: Mon May 03, 2021 8:22 am I shouldn't have specified 'S4 and later'. My real interest is in regard to the left SAAB door for the left 928 door. I want to buy a spare motor, but be sure I get one that fits the left door.
Hi Gary,
I believe left is left and right is right for these. So, the left-side Saab is left-side Porsche. Saab uses the same motor for front and rear windows, only difference is left to right.

Good idea to have a spare; it came in handy for me. I don't know that I will get another spare motor, though. Maybe just a spare Bosch brush off eBay because this is the piece most likely to fail (either the solder, the springs or the thermal fuse), it's straightforward to swap, and it's the same part for either side.

Matt
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By Gary Knox
#77697
I'm especially sensitive about the spare, as about 10 years ago, I'd prepped my '89 S4 for 3 days of track driving at Watkins Glen, and was backing it out of the garage for the 250 mile drive to the Glen. For some reason, I decided to roll the driver's window down and 'NO GO'. Quick change of plans, as the drivers window must be down when doing Porsche Club Driver's Ed events. Immediately checked fuses/wiring, etc. and finally removed panel and found I had power at the motor, but it was dead. Fortunately, I had a left door from a car that had been totaled when hit by a semi-trailer truck a few years earlier in storage. Quickly removed that motor, installed in the track car, and I was good to go, but about an hour and a half late. Without the spare motor, I might have missed the entire 3 day event. Removing the dead motor, putting the window down for the trips to and from, as well as 3 days/nights in Watkins Glen might not have been a good decision!

So - spare motor for the one used most often in my case was a good 'insurance policy'.

THANK YOU MATT for your suggestion - SAAB motor now in the 'spares' box.

Gary
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