Re: suspension question

[alex.fadeev@xxxxxxxxxxx]

kohlbren-m-d@domain.elided wrote:
> > Alex thanks for your quick response. I may not have explained 
> > myself well when trying to describe what the bmw mechanic said
> > needed to be done. i am not sure what the exact part names are 
> > but please bare with me. From what i remember the bmw mechanic
> > said that the springs should not have been as compressed as they
> > were. the car was just parked on a level surface. when he looked
> > up under the wheel well he pointed and showed me what he was 
> > looking at. The first few coils on the springs were touching 
> > each other.
> 
> This may very well be perfectly normal. 

Mike,
I would disagree that this is normal. All springs are preloaded to some 
extend, but if coil binding at static ride height is not normal. It will 
rub off the paint, induce corrosion and premature spring failure. 
I can not think of any way one can screw up front E36 strut assembly. Once 
the sprint sits on the strut housing and is squeezed between it and the 
camber plate, that's where it will stay. Even if the spring is wound to 
the wrong diameter (wrong application), or was not installed to fit into 
the camber plate/strut housing perch ends, it will still work. 
I would venture to guess that Paul was sold either wrong springs for his 
application, or that the springs themselves are junk.

> There are plenty of  "lowering springs" out there that have several
> so-called "dead coils" wound into them whose only function is to take
> up the slop when the shock is at full extension, 

The full extension is limited by the length of the shock. In coil over 
setups (like most front BMW suspensions), the spring is pre-compressed 
between the lower strut housing and the upper camber plate. All this at 
full shock extension (pushing by the spring). 
> as when the wheels are off the ground.  This prevents the springs
> from popping out of their perches.

Very true for the rear. Not the front. 

> > ... he said that it looked like they did not set the bump 
> > stop properly and it could cause the car to bottom out.

Paul,
Bump stop is nothing but a 1-3" long piece of foam donut that sits on the 
shaft of the shock. It could be either external or internal. 
Normally, the car should not be riding on the bump stops at static ride 
height. Unless the suspension was designed to utilize bump stops to 
imitate progressively increasing spring rate (aka stock E36 M3). 

> > ...he explained that i need to take it back to the shop that
> > did it and have them cut the "spring perch?"(the plate/housing 
> > where the spring sits in on the strut) and drop it an inch and
> > weld it back on.
> 
> While this is certainly something that gets done, it is typically
> only on really custom setups.  If you are buying off-the-shelf
> aftermarket bits specifically for the M3, then you shouldn't be
> doing stuff like that.

I 100% agree with Mike here. 
If your 'new' springs require cutting to work for your application, it's 
time for a lake test.
Namely, throw them in the lake. If they float, they are good and can be 
reused. If not, buy new. 

alex f
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