Re: E34 Steel/Al Control Arms

[alex.fadeev@xxxxxxxxxxx]

ThreedB <ThreedB@domain.elided> wrote:
> 
> Can I use steel control arms in my 95 540ia?

Which ones? 
E34s and 5's in general are not my forte.
Are they the same shape/geometry? If so, than yes.
 
> The car has aluminum arms now with 90kmi and dead bushings. The
> Bentley manual said you can replace the bushings in the steel 
> arms but the aluminum arms need to be replaced.  Is this a 
> geometry issue or merely a materials issue? 

I don't know the exact reasons behind Bentley advise, but in the E30/E36 
application, it is the aluminum fatigue issue.
E30M3 aluminum control arms have the same geometry as regular steel E30 
and some of the E36 control arms. But they cost three times as much. The 
Club Racing rule of thumb is to replace the aluminum arms after at most 
two seasons. Swapping bushings in between is OK.

> I want to know if I can buy new steel control arms (@$45 ea.)
> instead of aluminum (@$145 ea.).

Most likely yes. I would visually compare both arms to make sure they have 
either the same or nearly identical geometry. 
If the two are slightly different, compare the OE bushings as well. Some 
bushings may be centered while others are offset to achieve the same end 
result.

HTH,
alex f

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