Elec window adjustment.

[ss2115]

Hi.
Fixed my electric motor on a rear door window.
The metal housing popped off on one side - presumably by some strain in the mechanism. I've rethreaded and inserted a slightly oversize bolt and its all fine.

Did find what caused it.
The cross arm that traverses left to right on the horizontal track that has the single bolt adjustment on it had popped out of the plastic slide and so the window tilts on a slight angle going down and although it comes back up straight it must have been jamming into the side somewhere causing the motor to pop its case.

Anyway, I was able to push the metalball back into the plastic slide and all seemed well untill I'd put the window up/down a few times. Then on stopping in the up position, the metal arm would pull away from the track just enough to pop out again with a bit of a bang.

I checked my Bently but it doen't comment about fault finding and only goes through the adjustment of that arm.
I checked that adjustment and the window is dead straight when it reaches the top.
I loosened the bolt and got to know how the adjustment worked and carefully realigned it after a bit of practice - but its in exactly the same place it was anyway.

I bent the metal cross arm just slightly because I noticed it was at a slight angle to the slide bar when it pops off, and it seemed to help a little bit.

Both adjustment have it now working about 5 times out of six and then popping off while before I started it would pop off every time.

Has anyone else had similar fun with their electric windows and come up with a cure?
It doesn't look like its been replaced or anything - rivets hold it just like the book says and replacements are bolted (according to Bently anyway).

[whiskychaser]

Bottom right of the scissor 'X' connects to a roller that runs in a channel. Is the roller steel or nylon? If its nylon and some helpful PO has put grease in there that may be your problem. Crap builds up and causes that end to jam.
The motor keeps pushing and bends the whole lot out of shape. Make sure the side guides are clean too.

http://www.realoem.com/bmw/showparts...10&hg=51&fg=10

PS. Glad the motor is running the right way now

[ss2115]

Bottom right of the scissor 'X' connects to a roller that runs in a channel. Is the roller steel or nylon? If its nylon and some helpful PO has put grease in there that may be your problem. Crap builds up and causes that end to jam.
The motor keeps pushing and bends the whole lot out of shape. Make sure the side guides are clean too.

http://www.realoem.com/bmw/showparts...10&hg=51&fg=10

PS. Glad the motor is running the right way now

Hi. You've identified the correct sissor arm. However, mine is not a roller but a rectangular nylon slide with a hole in the centre that a metal ball on the end of the sissor arm pops into (and pops out of again as I explained).

There is indeed grease in the track and all around this slide.

What appears to happen is that when the window is going up, this slide (with the captured sissor arm) travels towards the electric motor and just at the last bit when the window finally meets the frame the sissor arm appears to actually pull away towards the outer door skin from the slide and the metal ball pops out.
At the same time as it pulls away it appears to rise very slightly as well so its no longer in line with the slide either and I have to put the window down a bit, move the slide along by hand to line it back up with the ball on the end of the sissor arm and then squeeze like all hell to get it to pop back in.

I'll certainly try and get in to the end of this slide and scrape out any muck I can find because if the slide isn't sliding quite all the way to the end as you suggest, then that could be the solution.

The adjustment on the end of this slide is more for getting the glass to go up dead parallel with the frame when it meets it, and I've adjusted this very carefully and its perfect. (it actually was anyway before I started, but I wanted to see if it made any difference to the problem).

If I was to say anything, I'd try to move the entire winder mechanism up about 1 - 2mm but its not possible as its rivetted into place and there are no other adjustments that I can see.
The Bently Manual confirms that there's only the adjustment on the end of the slide for getting the glass straight, and another adjustment for the glass bottoming out when fully opened and thats all.

Yes - It's nice to have the direction sorted out as easily as that.
Don't understand it as it shouldn't have made a difference, but it obviously did.
As per a quote in the thread, when you've eliminated the possible, it must be the impossible, or words that effect.

[whiskychaser]

If you can get rid of the grease I'd suggest using a little liquid silicon polish eg cockpit/tyre shine. Spray a bit in the channel and polish it with a rag.
Ive also used it on rubber side channels to help the glass slide but ours are felt so you cant do that.
One thing to check is that the bottom of the glass is actually in the runner all the way down. Its very easy for it to ride on a lip of the channel and is a sod to spot because its behind the panel. It goes up fine until the glass nears the top and then the bottom of the glass goes its own way. A clue may be that the outside of the glass isnt as tight up to the weather strip on the outside as it is on the other windows
HTH

[tim eh?]

Are you sure the plastic guide is in good shape? If the guide is busted, the arm will pop out... happened to me - it was just a chip off the lip around the hole but it was enough play for the arm to pop out every once in a while.

[ss2115]

I'll check both that the glass stays centre of its track and also that the guide isn't chipped over this weekend.

The guide will be easy to check as it looks like it will just slide out the end if its track once popped from the sissor arm.

Thank you both for the suggestions.

The glass moving out of the track just at the fully up position seems likely as the sissor arm seems to move away from the inside of the door towards the outside of the door at the last possible moment of closing, but I had put this down to the door panel flexing a bit as the motor closed the window glass tight.

[tim eh?]

pic for ya... my new guide came in yesterday, it's going to be so sweet to have all 4 door panels on.... at the same time!!!!