Wishbone "Eccentric rear Bush"

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paultv
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Post Thu Feb 07, 2019 12:05 pm

Bit of a general question:

BMW recommend you fit the rear bushing ( lollipop ) to the wishbone using a compound which aids fitting and then drys
after half an hour or so - creating a fixed joint between the pin and the rubber which then flexes during
suspension movements - ie. it's the rubber that twists and eventually falls to pieces.

If you fit solid M3 bushes what's the deal, I don't see solid rubber moving much, is the wishbone pin supposed to rotate in
the bushing then? How is it supposed to work?

or, does in fact, the rubber bushing twist enough ?


Paul :-)
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martauto
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Post Thu Feb 07, 2019 3:12 pm

Is it because the pin moves in all directions (small amounts ) and with the M3 bushes it keeps the movement down so the front legs are not moving around as much ???

Mart.
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paultv
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Post Fri Feb 08, 2019 7:57 am

Yes, I guess so, but is the pin supposed to rotate in the bush or be "rigid" causing only the rubber to flex which is how the standard bushes work.

Paul :-)
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Gavt
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Post Fri Feb 08, 2019 10:22 am

It is meant to be rigid, as in not rotate in the rubber but rotate the rubber slightly with a twisting action. The solid bushes are more stiff but the weight of a car and turning forces they do flex just fine just without the slop of the non solid bushes. For normal driving you probably won't notice the difference of solid v non solid. But you should for the eccentric.
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Brianmoooore
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Post Fri Feb 08, 2019 11:12 am

The bush, M3 type or standard must not rotate on the pin, and the bush must be set so that it is unflexed when the car is at normal ride height.
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paultv
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Post Fri Feb 08, 2019 11:44 am

OK, as I thought, same installation procedure for both items.

Thanks

Paul :-)
4th May 1990 325i Convertible.

BMW E30 Cabriolet Best Mod Ever:

https://bmwe30cabriolet-wdm.blogspot.com/