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Subject: Front window regulator replacement Author: yaofeng : member since November, 2005 : 1948 posts Posted on: 2009-05-28 20:58:15

Saturday my older son took his girl friend to Atlantic City in the 540it. He called me Sunday saying the passenger side front window was stuck half way. It would not go up but will go down.

I knew I must have screwed up the last time I took it apart to fix the inop window when I got the car. So it is time again to take it apart. I did yesterday.

After bench testing the window regulator with battery power in the garage, I found out what was the problem. Here is the front passenger side window regulator. There are four cable guides, two on each rail.


Here is a view of the bottom guide on the front rail near the top of the picture. It is a tab which is part of the rail sheet metal.


The cable guide tab has to be at the right angle protruding out of the rail. Too high it interferes with the window glass. Too low it interferes with the seat for the glass pulled by the cable. The window was inop when I got the car. The first time I fixed it the top rear guide tab was bent as it was hit by the seat as the cable pulls it up. I bent the tab back. But the angle wasn't right when I did. It was too low. As a result the rear seat hit it again going up. That's why it would not go up all the way.

Since I have already taken it apart I'll describe how I put it back together. If you look at the window regulator, there are two rails. Each rail is bolted to the door at the top and bottom. The motor is bolted to the door by two bolts. So there are a total of six bolts on the regulator. Four are torx. Only the bottom two are hex (10 mm socket).

To install, you should use battery power to move the seats to an inch or so below the bottom cable guide tab. Disconnect the car battery before you proceed.

Next, remove the glass if you have not done so already. The glass sits on two seats which are pulled by the cable. Each seat has a rubber cusion sandwiching the glass pane.


During removal, you loosen a torx bolt on each seat to loosen the grip on the glass. After the seats are separated from the glass, the glass pane can be tilted and pulled out.


The glass has to be pulled out because the top bolt on each rail and the top bolt for the motor cannot be installed with the glass in place even all the way up.

Next put the regulator in with each rail resting on the bottom bracket, bolt finger tight.


With the rail bottom positioned, swing the top to the bolt hole and bolt it up. There are three torx bolts, one for each rail and a third for the motor.


The bottom bolt for the motor clamps a bracket on the door horizontal reinforcing rib.




Next tighten the bottom bolt on each rail.




With the window regulator installed having the seats an inch or so below the bottom guide tab on the rail, you can insert the window glass through the slit in the opening. It was drizzling when I did this.


Lower the window glass along the guides on the front and back of the door to rest on the seats. On each seat there is a plastic stop to adjust the glass height so it remains parallel to the guides on the door. Loosen the bolt on the stops to adjust the height so the bottom of the glass sits on the stops. Tighten the seat with the rubber cushion sandwiched in between.




After both seats are tightened, connect the battery and do a test drive. Make sure the window goes up and down properly.


The rest is trivial..

There is only one thing I want to add. Make sure the plastic catch at the center of the door card is on the door card rather than the sheet metal tab. When You remove the door card you pull it up after the plastic rivets are all loosened. The plastic catch may stay on the sheet metal tab. You should remove it to install it on the door card so when you install you just push the door card in. I think most of you who has done the door card removal on either the e34 or e39 know this.


AIM: yaofeng4249
'95 525i 5 speed, built 5/94
'95 540ia built 7/94, converted to 6 speed w/ 93 E32 M60 4.0 Nikasil engine
'01 540it, built 6/01
'03 325i 5 speed, built 9/02

• Front window regulator replacement (pic) (url) - yaofeng 2009-05-28 20:58:15 (1226 views)