Rear Window guides

E28 technical advice asked and given! Troubleshooting, modifications and more.
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M3 Cereal
Posts: 28
Joined: Jan 14, 2013 1:07 PM
Location: Baltimore Md

Rear Window guides

Post by M3 Cereal »

To my understanding the rear window guides aren’t really made anymore and obtaining them can be quite costly.

My question is do the front window guides work in the rear doors?

Recently replaced my front driver and passenger window guides and they made a night and day difference in the function speed of the windows and the amount of wind noise in the cabin.

My rear windows are all jacked up and need to be re adjusted, but before I dive Into the rear doors I would like to replace the guides at the same time if possible. Anyone know if they will fit?

Thanks

Front driver - 51321889787
Front passenger - 51321889788
Rear driver side - 51341889007
Rear passenger side - 51341889008
Federico
Posts: 545
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Rear Window guides

Post by Federico »

They should work, but you'll need to make a second mitered joint for it to fit.
It might be worthwhile to do an Amazon search for "rubber glass run channel", and hack a $10 seal instead of a $90 one.
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: Rear Window guides

Post by Mike W. »

Many body related things are the same between E12 and E28, window channel might be one of them. Might, I don't know. On First Fives there's a very old FAQ about an aftermarket part that apparently works well. Might be worth investigating. Last I looked they were still in business at least.

http://www.firstfives.org/winchan.html
kojo96
Posts: 798
Joined: Mar 31, 2019 7:39 PM
Location: Pleasanton CA

Re: Rear Window guides

Post by kojo96 »

These window guides should be purchased new, regardless of price , waiting will only cost you more.
I can't imagine hacking anything to work in place of the originals, you'd never get a good seal on both the glass or door frame.
Follow Mike's link and see if the reproduction seals are available, that'd be the 2nd best option to finding new OEM.
beaseac
Posts: 14
Joined: Apr 25, 2021 3:32 PM
Location: South Carolina

Re: Rear Window guides

Post by beaseac »

Has anyone found a source for the rear window channel guide felts? I have been looking but haven't had any looking finding anything.

Any chance there is another car that has the felts readily available that also fits the E28? I've been searching online for some generic felts but the ones I found seem to be a bit small (unless my measurement is off).

Thanks!

Adam
jhh925
Posts: 913
Joined: Jul 11, 2015 12:23 AM
Location: Reno

Re: Rear Window guides

Post by jhh925 »

Mike W. wrote: Jan 08, 2022 12:34 PM Many body related things are the same between E12 and E28, window channel might be one of them. Might, I don't know. On First Fives there's a very old FAQ about an aftermarket part that apparently works well. Might be worth investigating. Last I looked they were still in business at least.

http://www.firstfives.org/winchan.html
I bought a sufficient length of the window guide rubber referenced at that FirstFives post to re-do both rear windows in an E28 I'm working on. (FYI, the FirstFives post points you to Restoration Specialties and their product number AS 990029.) The cross section on the original BMW part is not symmetric; that is, there's a definite inside and a definite outside. The outside profile sort of sits up against the door frame nicely. The aftermarket stuff from Restoration Specialties is symmetric, (so it's not a perfect aftermarket replacement), but it seems to be the right size for our doors and the quality seems high quality. However, they store it on spools, so when you get it, it's wood up in a loop. When you unwind it, the portion of the seal that will face the "inner periphery" of the seal is longer than the "outer periphery." As a result, it's a PIA trying to straighten this stuff out. I've had it hanging vertically for a few months now with no perceived improvement in straightening it out.

That said, *IF* you can get it straightened out, the quality of the rubber & flocking seems very good. And probably if I had the patience, I could just measure where to cut along the back side of the new rubber, glue it up, install it, and then hope that the sizing issue works itself out after a while on the car.

My thought was to make a jig to cut a 90°notch in the seal, with each side of the 90°notch being at a 45°to the line of the seal, and leaving the back or "spine" of the seal uncut. That way, I can fold up the seal to a 90°corner, glue the mating surfaces, and use the spine to help hold it all together. (Disclaimer: This idea was form others on the board, not totally my original idea.) I still haven't done this, so don't flame me if it doesn't work for you.
Blue Shadow
Posts: 10195
Joined: Feb 12, 2006 12:00 PM
Location: SE PA

Re: Rear Window guides

Post by Blue Shadow »

jhh925 wrote: Feb 22, 2023 7:14 PM and use the spine to help hold it all together.
When my guides started to break at the corners, I used a chunk of burlap and some Goop to glue a backing to the corner. First one was the driver's door at the mirror bend. That made the guides last another 15 years before I replaced them due to the outside section against the window splitting lengthwise, the common failure.
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