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2005-2014 Mustang Lower Control Arms (LCA) and Axle Alignment

As some of you may know, a few weeks ago I ordered some lower control arms for my Mustang. I decided to go with the UMI Roto-Joint units because of their claim of providing the proper articulation like a spherical rod-end while avoiding most of the degradation in ride quality. They do this using two different types of bushings, a traditional polyurethane bushing on the chassis side and a unique bushing called Roto-Joint on the axle side. The Roto-Joint is a spherical-like design which uses a pivot ball lined with a greaseable delrin race, which replaces the metal housing in a ball joint and absorbs more shock reducing NVH.

So far, the control arms have been living up to the expectations. I was just smiling ear to ear the first time I floored it. I was in 1st gear and the last time I was that aggressive with the throttle in 1st gear, wheel hop was terrible. Wheel hop is not 100% gone, which is to be expected since you need upper control arms to get rid of all hop, but it was very brief and was more like a mild shudder or vibration than a hop. Not only that, but traction is hugely improved and the rear end feels more solid going over bumps. To learn more about them, visit: 2005-2014 Mustang Lower Control Arms- Poly/Roto-Joint Combination.

Unfortunately, though, I couldn't install the LCAs myself because I didn't have the time to do it before the last track day of the season. I wanted to try it out at the track before having to wait until next summer so I got it installed. I did have some time to check on it over the weekend, though, and found that it needed adjusting. In the process of uninstalling the control arms, the rear axle moved and the control arm was no longer lined up with the mounting hole on the axle side so the bolt could no longer fit. Here's what I did to fix it.

1 - The first thing I had to do was jack up the rear end of the car. Since I usually work under ramps, the rear suspension was fully loaded so I couldn't move the axle. For add a layer of safety in case the jack stands fail, I slid a portion of the ramps under the rear tires to keep the rear end raised. Some people also take out the wheels and put them under the frame to support the car in case of failure.

2 - Unbolt the Watt's link or PH bar from the axle side to allow the axle to articulate more freely.

3 - This is the third step that I did but I don't know if the next step would have eliminated the need for this. I articulated the axle up/down and front/back on the driver's side until I could fit the bolt through the axle mount and control arm. Do not tighten the bolt.

4 - With the car's weight still supported on jack stands, jack the rear end from in front of the diff housing, right behind the flange where the driveshaft bolts to the diff. The housing is long and jacking towards the end of it rotates the axle and allows the bolt holes to line up. Be sure not to jack up too much to prevent starting to support the car's weight from the diff. You are NOT supposed to jack the car from the diff and although some people say they do it, I chose to follow the manual and never do it.

5 - Slide the second bolt in but do not tighten.

6 - Raise the car back up so that you can slide the ramps fully under the rear tires and then lower car securely on the ramps.

7 - Tighten the bolts. Torque spec is 70 lb-in.

I was able to rotate the axle in step 4 so that it lined up perfectly. I'm not sure if having one of the bolts in (step 3) provided a pivot point and allowed the axle to rotate to where it's supposed to be or that was just a waste of time and effort so I would recommend trying that before anything since it takes very little time and if the holes don't line up, try to get one bolt in first. It would be easier if you took out the springs since they provide resistance to axle movement. I didn't do that because I hadn't tackled it before didn't want to add more time to the job that was already starting to take longer than it should but otherwise I would have. It would also be much easier if you had a friend around to lend a second pair of hands, specially if you don't take out the springs. I managed to do it alone so it can be done but it would be much easier with extra help.

It can be frustrating and take a lot of trial and error to get them to line up and when the car isn't on a lift, that can be a huge challenge due to the lack of space. Make sure the car and the jack stands are secure before you try anything and don't attempt to move the axle by applying any sudden force. Also note that this is not install/uninstall instructions. Follow the manufacturer's instructions for replacing the control arms. This is only for attempting to align the axle should it get out of alignment.


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