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Replacing front window motors with e28 ones on late 73 and after cars.

Bmachine

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Creating a standalone thread after discussing the subject in the parts section in order to put the info in a more searchable place.


I’ve been diving into the process of cleaning and upgrading the infamous window motors and regulators for the front doors. Mine is a 74 so it is a different setup than earlier cars.
I encountered several issues (related in that earlier post) which led me to test the difference between the original e9 motors and the e28 ones. As mentioned many times elsewhere on the forum, these are the rear e28 units.
Observations so far:

- The bolts for the 74 motors are too long to use in the e28 motors. They rub against the inside of the mechanism. So you need to either use shorter bolts or add washers. DO NOT use the e9 bolts on the e28 motors!

- It looks like the reason why my driver side regulator did not mesh correctly with an e28 motor is not because of the motor gear is lower (although they are indeed slightly lower) but because my regulator frame is slightly bent. The e28 motors are less tolerant of any deviation in the frame of the regulator.

- After swapping the motors on the same regulators both on the right side and left side the difference in speed between the e28 motors and the e9 motors is actually quite significant: about seven seconds for the E9 motors and three or four seconds for the e28 motors. This is a bench test with the motors activating the regulator. So the windows are not being lifted at this point.
 
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nosmonkey

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Cleaning alone makes such a huge difference on some cars. When I pulled by rear window regs out the grease had almost solidified into solid lumps. Stripped down and cleaned with e28 motors the difference is staggering, are you also running relays at the windows to improve performance further?
 

adawil2002

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FYI: Only Rear door E28 motors will work on E9s. So one needs 2 Rear Left & 2 Rear Right motors.

I've cleaned and lubricated all 4 of my window tracks as well as cleaning the winding transmissions. I'm still running the original "tuna can" motors, now they are 3 seconds to down & 3 seconds up, I'm fine with that.
 

jmackro

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Is that the difference between load-shedding relays and regular relays?
Well no, not really. The "Load Shedding Relay" is the proper name for a specific relay on e3's & e9's that powers many of the electrical devices. This allows the ignition switch to avoid carrying the current that it would otherwise have to handle to power these devices directly. But at the end of the day, the Load Shedding Relay (proper noun) is just another relay (improper noun), though one with a fairly high current-carrying capacity.
 

Bmachine

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Adding this link in which Gary Knox has some very useful tips. I wish I had seen that thread before starting this project.
 
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Bmachine

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A few more observations to keep in mind for this project:

- While you have the regulator out it is a perfect time to do a few more things which would be very difficult to do otherwise:

- Add Dynamat or equivalent soundproofing material on the door frame.

- Check to make sure that all the nuts that hold the outside trim piece are there and tight. Any loose bolts or missing nut will create a really annoying vibration every time you close the door.

- Obviously check to make sure all the drain holes at the bottom of the door are clear for water to evacuate. Clean up the bottom of the door from all the crap that fell down there the last 45 years.

- Get a new plastic weather shield ready to go before putting the door card back on. The old ones are always falling apart and now is obviously the time to replace it. Also get the proper glue to stick it on.

- Order new door card clips beforehand. Inevitably some of the existing ones will be broken.

- Order new grommets to keep the door lock linkages from rattling. Now is the time to replace those as they will inevitably have disappeared over time. 3 per door.

- When reinstalling the regulator to the door frame, be sure to use a short bolt (M6-8 or possibly 10) in the front most hole. Otherwise it will bind against the moving mechanism behind.
 
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Willem Tell

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I was looking for a SPAL fan the other day, and the site offered this motor. The can looks much like an E9 motor. Has anybody seen this? Looked at compatibility?
1590694861163.png
 

Bmachine

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Bo, would you add that to the interior-facing surface and carve out the holes for access?
Yes sir! I explained it in this thread:
 
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