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Coilover install question, rubbing the upper control arm when unloaded?

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Old Jun 10, 2013 | 09:02 AM
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Default Coilover install question, rubbing the upper control arm when unloaded?

Hi all,

I'll call for tech support when they open this morning but was wondering if I am the only one that has this problem:

2000 FRC race car, just installing Spherical bearings, camber plate kit and coilovers this weekend. As I am trying to bolt it all back together I notice that the rear section of the upper control arm is touching/interfering with the coilover. This would NOT happen if there was weight on the spring but it is touching so badly unloaded that I cannot bolt the upper arm back on without jacking up (loading) the suspension.

I would not worry on a street car except it is very possible for the suspension to completely unload on certain tracks. At that point that could crack the upper control arm. There are pics of my car in the air floating around the web.

I tried a VERY small amount of grinding and that could be the solution but not sure how thin I could safely take that part of the arm.

Anyone else have this issue? I am 100% certain the components are installed properly. Not an issue at all in the rears, just the fronts.

Any advice/experience would be MOST appreciated!
Cassidy
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Old Jun 11, 2013 | 09:32 AM
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Ok,

Now I have the other 3 wheels set up and they are ALL fine. The driver front is the ONLY one that is rubbing. After working with it and some fine sandpaper it is only brushing it but still does interfere. I am wondering if the casting and the drilling in the lower control arm is askew just enough that it is causing the shock/spring to move backwards a degree or two. If you load the suspension with a floor jack underneath, the problem goes away.

Called the company that I bought the parts from, they are talking about it in Engineering. It is a very reputable equipment company and sponsor here so I will wait until it is resolved All I can think is that if I have this problem someone else might, too. Built on a Friday kind of thing.... I am far more confident it is something on MY car than on the parts. They are works of machined art....

Will keep this post updated as someone may need my solution in the future...once I have one that is!
Cassidy
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Old Jun 11, 2013 | 09:58 AM
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Alignment differences or rather chassis differences which cause the cam bolts on your FL to be set differently than the FR? You could possibly shim your upper control arms before setting the alignment to help but that doesn't sound necessary.
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Old Jun 11, 2013 | 05:54 PM
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On one side my front spring rubs on the control arm.


Then if you look at the rears, you will probably find the spring hitting the tie rod. They should make 2" springs for our cars.

Steve A.
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Old Jun 12, 2013 | 07:44 AM
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Well it does appear to be just variances in the castings and the alignment of the stars. It is truly ONLY at full travel (droop if you will) that it even rubs and after reseating the lower mount I have it down to almost none.

As per the recommendation of the manufacturer I pinned it all back together last night. Got too late to test drive but I have to corner balance and align it this week anyway.

Thanks for the pics Biker, helps to see. Rears are fine oddly! Now to see if the FATTY roll bars hit the brake ducts!

Cassidy
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Old Jun 12, 2013 | 04:11 PM
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whatever you do, do not file anything on the spring! It is a different alloy and requires completely smooth surfaces to prevent stress risers that will crack open over an unknown period of high OR low loading/cycling. Google fatigue cracking in metals...
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