Project Grey Mustang 5.0: Part 7 – Testing BMR Suspension’s Rear Control Arms


After adjusting them, the new control arms simply slid into place, though they also required a bit of gentle tapping from a small hammer due to the super-tight tolerances.  We also had to use a floor jack to reposition the axle a few times, since it shifted while the control arms were removed.

Recall that lowering a live axle car results in the lower control arms sloping up towards the axle, causing poor anti-squat geometry and roll understeer.  The BMR brackets allow you three settings: the highest hole allows near-stock geometry even though the vehicle is lowered, while the other two allow increasing levels of anti-squat and roll oversteer.  My personal preference is a touch of roll oversteer, as I feel it makes the car feel “smaller,” so I set the arms to the center hole.


Here’s one of the control arms installed.  I chose the middle hole for what I feel is a desirable level of anti-squat and roll oversteer.
Here’s the lower part of the rear suspension all buttoned-up.

At this point, we had finished installing the lower control arms, relocation brackets, and panhard rod and brace.  The upper control arm and mount was next, but that is very difficult to install with only ramps and jack stands.  (One of the bolts requires 350 lb-ft of torque!)  Part of the adjustment process also requires a four-post, drive-on lift.  So we went back to Justin’s Performance Center to let the experts handle the installation.


When in doubt, leave it to the experts!

First, I’d like to show you the stock upper control arm.  It’s a very strong piece of stamped steel with a squishy (there’s that term again) rubber bushing.


Stock upper control arm.  Notice the rubber bushing with all the voids in it.

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