560 SL power window spring

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John 560SL - 05 Mar 2009 17:07 GMT

The coil spring that helps lift the window uses a slotted metal stud
to maintain tension. The motor mounting screws became loose and my
slotted stud fell out. It looks like it was originally installed into
a hole in the sheet metal and possibly crimped on the back side. If I
just put this stud back in place will the coil spring hold it in place
or do I need to make sure that it is better attached to the sheet
metal? (Of course you cannot get behind it to recrimp it without
taking the whole thing apart.) I am thinking of replacing it with a
bolt and nut assembly where I cut a slot in the shaft of the bolt to
hold the coil spring tang. Secondly, do I need to rotate the coil
spring to add tension to it before putting its tang back into the slot
in the stud? If so, how many turns?

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Roland Franzius - 05 Mar 2009 20:32 GMT

John 560SL schrieb:

> The coil spring that helps lift the window uses a slotted metal stud
> to maintain tension. The motor mounting screws became loose and my
[quoted text clipped - 8 lines]
> spring to add tension to it before putting its tang back into the slot
> in the stud? If so, how many turns?

The spring should be adjusted so, that in the half open position its
torque force at the short lever arm is balancing the weight of the
window at the long lever arm. The window weights around 5 kg or 10
pounds. The applied torque factor depends on the lever ratio of arm
length to window support and coil diameter, perhaps some 10 N*m or 50
pound*inches.

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Roland Franzius

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Tiger - 08 Mar 2009 16:58 GMT

Just buy new window regulator... it is not too expensive... online autoparts
such as autohausaz.com or even ebay.

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trader4@optonline.net - 09 Mar 2009 14:50 GMT

> Just buy new window regulator... it is not too expensive... online autoparts
> such as autohausaz.com or even ebay.

Bingo! I saw this post a few days ago, remember working on mine in a
similar car and know the spring he is talking about. But it's been a
while and it didn't occur to me that the spring is actually part of
the window regulator. The only thing that still puzzles me is he
said that the bolts that hold the motor loosened and then the spring
came undone. If this mechanism is the same as the one in my 116,
then I don;t see how that could happen. The motor has nothing to do
with the spring, which is directly fastened to and part of the window
regulator, right?

But in any case, it seems likely a new window regulator is the
solution. I got mine on Ebay few years ago. Think it might have
been $60 or so.

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