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Upper Control Arm Install Question

9K views 19 replies 7 participants last post by  PMDmustang13 
#1 ·
Hello all,

I am getting ready to install a BMR upper control arm with their bracket and I have a stupid question: do I support car at the chassis to let the axle hang or do I want the suspension loaded for install?

BMR did not specify where to support the car, but it seems to me the suspension should't be loaded.

Thanks for any help!
 
#2 ·
There is not a lot of room to do the install with the suspention loaded. Maybe this video will help.
 
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#3 ·
I have watched that recently and it does help a lot. I'm doing this in my home garage and I have no lift available to use.
 
#6 ·
Thanks for the help, guys. A buddy stopped by yesterday and we got the bolt loosened inside the car with a 24" breaker bar.
 
#8 ·
Ha ha! It took both of us; he pushed from the passenger side and I pulled from the driver's side. I think it's time for me to invest in a better impact gun.
 
#9 ·
You are going to want to use a torque wrench to torque that bolt under the seat. It was difficult but I was able to get it torqued back to specification by myself.

When I installed mine I had an issue with fitment of the 2 other holes that you install bolts to attach to the frame of the car. I spent a lot of time enlarging the holes so the bolts would go in to the frame. And one bolt was a pain in the butt to get torqued in all the way as a result.

Make sure you contact BMR to make sure based on what your current setup is as to which setting with the mount you want to use. It makes a difference.
 
#10 ·
Thanks for the advice. That's disappointing that you had to enlarge the holes on the bracket. My car is stock height and I have no intentions to lower it, so I believe I want to use the lower mounting.

Are you happy with the performance of the BMR rear control arms? My car has terrible wheel hop at the drag strip I hope to eliminate it with LCAs and UCA.
 
#13 ·
First I want to say yes I am happy with the performance of BMR rear control arms. I had wheel hop on the street and the first thing I did was go with BMR relocation brackets, using 1 hole lower than stock when my car was not lowered yet, and went with poly poly bushings on LCA's. The wheel hop disappeared and my traction increased.

The following is from an email with Kelly at BMR. If you want the full email with the diagrams he provided I would need your email address. But below is the text of his response to me. AS = Antisquat and IC = Instant Center if I remember correctly.

Paul, explaining AS/IC is very complex. I will attach some pictures at the end of this email, that I made up years ago, to help you understand.



I have never changed my mind about suspension geometry. If I recommend something to someone, there is definitely a reason for it. IE: If someone is stock height…and they tell me they “will” be lowering the car….then I tell them to install the UCA into the upper position. But they “should” use LCA Relos, if that is the case (when they lower the car)



The upper most hole I speak of, is the highest hole from the ground, when the parts are installed on the car.



A stock ride height car, without relocation brackets, works best with the UCA in the lowest position. Once the car gets relocation brackets, then the UCA needs to be moved up. On a lowered car, I always recommend LCA Relos, and the UCA in the Upper position. If someone does not want LCA Relos, or does not have them, and they have a lowered car….the lowest position of the UCA is going to work better than the upper – but I don’t prefer this.



You read what I posted correctly. The upper positions are designed for a lowered car, that utilizes our LCA Relos. The lower hole, is designed for a stock height car, and no relos. BUT – a lowered car (with no relos) can work well in the lowest position, as well.



In other words, if someone never uses our LCA relos, they will likely have better luck with the lower position on our mount. If someone does use our relos, I always recommend the upper hole on the UCA Mount.



The goal is to have the angles (imaginary) intersect at a point that provides the best overall performance. When you drop a car, by lowering it, you are already dropping the angle down, of the UCA – because the UCA is attached the body of the car that gets lowered.



When you have a lowered car, THEN lower the UCA down….and also drop the LCA down in our brackets – the angles are WAY to aggressive/steep….and you “hit” the tires way too hard…and you also run into instability issues in corners.
 
#16 ·
Thanks for the help, that e-mail from BMR is a good read with lots of info.

So here's a curve ball: the UCA mount I received has three mounting positions and there is nothing in the instructions on which one to use. I know with the two-hole I should use the lower, but I didn't know the there was a three-hole mount. I'll call BMR and see what they say.
 
#17 ·
Please post a photo of what you are talking about. I am assuming you are saying you have 3 holes in the mount for attaching the UCA instead of 2 holes like mine. See My photos.
 

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#18 ·
Yes - exactly; I'll post some photos soon.

I called BMR today and the tech said three-hole is a new design change. For my stock height-car he said I should use the center position.
 
#19 ·
I talked to them a few days ago about mine. Also the three hole design. He recommended the upper hole as I am lowered but also said that if I use the upper hole that I should be using LCA relocation brackets which I already installed.


Sent from my iPhone using Tapatalk
 
#20 ·
maybe the new 3rd hole is for guys that raise their car for off road use?
 
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