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Discussion Starter · #1 ·
Replacing the upper control arms is a bit challenging, but only because of the accessibility to a couple of nuts and the lack of room to slide the bolts out. Simply put, Chrysler could have made it easier… but they didn’t. Aside from that, it is a very straightforward swap and is not too difficult to do with standard tools.

I changed mine out during a larger suspension replacement job on my ’06 300C RWD. The procedure would be the same if you are replacing them with aftermarket upper control arms as well. *Note – some pictures will show other suspension parts removed as this was part of a larger job, but that is not necessary to just change the upper control arms.

Upper control arms
PB Blaster (not necessary, but helpful)
18mm socket
13mm socket
ratchet and extensions
18mm open-end or combination wrench (multiple lengths)
6mm alan wrench
pinch clamps
torque wrench ratchet

First, raise your car and safely support it on jack stands, then remove your wheel…

These upper control arms are simply held on by a bolt and nut on each end of the control arm’s wishbone by the top of the strut, and by one ball joint stud and nut on the top of the knuckle. We will start with the ball joint that is attached to the knuckle. Go ahead and give the nut a good soak of some PB Blaster if you wish, as seen below…

*Note: In order to fit my fat tires on my car, you will notice that I have shaved down the head of the ball joint stud on the UCA so that it is flush with the bottom of the nut. Yours will likely look a bit different with a few threads still sticking out from the nut. Additionally, I have shaved down the inside of the control arms – again, for the fat tires. Yours will likely look a bit different with a couple of ridges still running up the knuckle arm…

Now we need to loosen the nut on the ball joint stud. Grab an 18mm socket and ratchet and crank it loose. If the ball joint stud spins with the nut, then no worries – there is a 6mm alan hole up the shaft of the stud (look closely at the pic above and you can see it, even though my studs are shaved down). You can hold/anchor the stud by inserting a 6mm alan wrench/hex key into the end of the bolt, then crank off the nut with an 18mm open end or combination wrench… but don’t crank it off all of the way…

Now for these ball joints on these UCA’s, they gave me quite a challenge to bust the tapers loose. The Miller Tool 9360 is a great little device that works wonders on busting these tapers loose, but I don’t have one of those. Instead, I opt for the “bang it with a hammer” technique. Using a hammer, smack the round ring that is molded into the outside part of the knuckle right next to the taper to shock it loose. If it doesn’t come free, use a BFH. Still not loose, use your floor jack and put a bit of a load on the suspension by jacking up the lower control arm right where the strut attaches - a bit of an angle on that arm can help a bit. Still not loose, then break out a torch and heat up the knuckle. It will come, but might take some good precise whacks to shock it free.

Once loose, you can keep the nut on the ball joint stud for now to keep the knuckle from coming downward, and we will move onto the two bolts at each side of the UCA’s wishbone. The bolts run from the inside, near the springs, through the UCA’s and into the engine bay, where they are secured with a nut. The only smart thing Chrysler did with this job is add a little bracket to the bolt heads so that they don’t spin when you are loosening the nuts in the engine bay. You can see the one on the left side clearly in this pic…

So now all we have to do is loosen the nuts on the engine bay side, slide the bolts out, and our UCA’s will come right out. Well, this is where it gets a bit frustrating. But patience will win this battle. These nuts are in the bay, on the forward and rear side of where the strut is attached.

On the driver’s side, the front nut is right in between the coolant tank and the strut tower. This is a view from the side of the car – see it down there… facing forward toward the coolant tank… (circled)

Now the pain begins with the rear one. It’s on the opposite side of the strut tower. Here is a view of it from the side of the car, looking down into the pop-off door on the cowl that covers the brake fluid reservoir… see it down there, facing toward the rear… (circled)

On the passenger side of the car, they are in the same location obviously. The front one is located between the fuse box and the strut tower. This is a view from the side of the car – see it down there… facing forward toward the fuse box… (circled)

Again, the rear one is the tough one. Can’t find my before pic for that one (might have been so frustrated I didn’t take one), but it is on the rear side of the strut tower, facing toward the rear.

So now that we know where the four nuts are, we just need to crank them off to be able to pull the bolts and get those old UCA’s out. Well, depending on how busy your engine bay is, a bunch of stuff needs to be moved to access these nuts. And my bay is BUSY…

First and foremost, if you have a firewall cover, that will definitely need to go. Some people pull the whole windshield cowl and wipers, but that’s really not necessary. It would make access to the rear nuts easier, but I preferred to sweat through the tough access instead of pulling all of that. But the firewall cover had to go.

On the driver’s side, the coolant tank needs to come forward to access the front nut. But as you can see, that means the power steering reservoir and the intake need to move to make room for the coolant tank to come forward…

On the passenger side, if you have an ABS cover as I do, that needs to come out so you can access the front nut...

For the rear nuts, as I said earlier you can pull the entire cowl, but I just removed the door that covers the brake fluid reservoir on the driver’s side and the plastic grid thing that covers the ECU on the passenger side. Some people also unbolt and move the ECU for better access/visibility, but I got it done without having to do so. But I did remove the plastic round cylinder thingy that is attached to the ground point with a couple other ground wires, just behind the shock tower on the passenger side. Here is a pic from the side of the car – note the ground point stud is free, ground wires taped up, and cylinder thingy now loose… (this is the same cylinder thingy that you have to reposition when installing the firewall cover)…

So at this point, my bay was nearly gutted and looking something like this…

But I had clear access to the front nuts on either side…

Before we crank those nuts off, one tip I found on LXF is to use some pinch clamps on the brackets connected to the bolt heads in the wheel well. The brackets keep the bolts from completely spinning, but they do move a bit once they are loose, making it tougher to use a ratchet on the front nuts and everything helps when attacking the rear nuts. Here is a clamp on the driver’s side front bolt bracket…

Now grab a ratchet and an 18mm socket and crank off the front nut…

Then switch the clamp to the rear bolt bracket and go after that rear nut. I used a ratchet on the driver’s side rear nut – handle facing inward. This was a challenge because you have very little room and it is a bunch of tiny turns until it’s finally free. And you are largely doing this blind – only by feel. It’s very tough to see in there with your hands and tools taking up the little bit of space that is available. Use what works best for you: ratchet/socket, open or closed end of a combination wrench, or probably best would be a self ratcheting closed end combination wrench. But whatever works. Be patient… you’ll get it… eventually. ;) Here’s a pic with the ratchet/socket I used on the nut, looking from the side through the brake fluid reservoir door…

So now that the nuts are free, you’ll see the last problem. Back in the wheel well, when you try to slide the bolts out to free the UCA, you’ll see that right before they pull all of the way out, they run into the spring…

Ugh. Come on Chrysler! But again, not a big deal… just another step needed – we’ll have to drop the strut. Grab your floor jack and put some pressure on the lower control arm where the strut is mounted…

Using a 13mm socket, remove the three nuts on the top of the shock tower in the bay…

Then lower the strut down and slide it outward a bit once the bolts clear the mounting holes at the top. You don’t need to move it out much, just enough to pull the bolts from the UCA. And don’t worry – the spring is self-contained in the strut cap so it won’t de-compress – no special tools will be needed to compress or reinstall it. So remove the nut on the ball joint stud, lift the UCA off of the knuckle, slide the bolts out of the UCA wishbone arms, and your UCA is finally free…

Same goes for the passenger side. Although I should mention the rear nut on the passenger side is probably even tougher to access. I used a closed-end of a short 18mm combination wrench with the handle again facing inward, and it took many many small turns… but I eventually got it… after screaming quite a few MFers.

Installing the new UCA’s is simply the same thing in reverse order. Slide the new UCA into place, slide the bolts into the wishbone arms, then loosely screw on the nuts in the engine bay. Jack the strut studs back into their three mounting holes and tighten the 13mm nuts using a torque wrench to 20 ft lbs while you have a load on the strut with your floor jack.

Place the new UCA ball joint stud into the knuckle and tighten the 18mm nut to 35 ft lbs + 90 degrees. Both of my tapers grabbed and held, so I was able to use a standard torque wrench. But if the ball joint stud is spinning with the nut, then you will have to use an 18mm combination wrench along with a 6mm alan/hex head in the shaft to anchor/secure the stud while tightening the nut. Tighten as good as you can, unless you are lucky enough to have an open ended torque wrench to get it to spec. You can always ask the alignment shop to check those later.

Then, with a load on the suspension from your floor jack, tighten the UCA wishbone bolt nuts to 55 ft lbs. Again I was able to get a torque wrench on the front nuts and the driver’s side rear nut, but there was no way for me to get even my small torque wrench on the passenger side rear nut – so I just tightened that as well as I could.

Now just put your engine bay back together, depending on how much stuff you needed to move… firewall cover, plastic grid over ECU, ground wires and plastic cylinder thingy, brake fluid reservoir door, ABS cover, intake, power steering reservoir, coolant reservoir, etc.

And that’s it! Congrats, new upper control arms are on! Really is a “simplistic” job with just two bolts and a ball joint on each side - but as you can see, there are some challenges due to the locations and access to some of the nuts.

Hope this helps! :fing02:

Premium Member
5,718 Posts
You need to be commended on such great write ups.
Sent you a PM with a small recommendation before moving it across.
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Premium Member
3,999 Posts
Discussion Starter · #3 ·
Fixed it. Thanks man. :fing02:

16 Posts
I think that as the strut needs lowering I would remove it. I would also cut the anti rotation brackets off the inside so that all I needed to do was access the strut top tower nuts with a spanner just to hold them and use a ratchet from the inside. They should have done this at the factory with a weldnut on the outer and strut removal to get bolts out.
My 2 pence worth.

88 Posts
hey there, I know this post is a bit old, but I did my upper control arms with my dad who is a former mechanic. We're running into an issue where we think the knuckle is catching spring and causing a popping sound. OR I noticed you mentioned to shave the UCA for big tires so I'm thinking that may be it? I noticed you actually loosened your strut assembly from the top and we just put the Jack under the strut itself after we loosened the bolt from the bottom connecting to the knuckle . Is the loosening of the strut from the top necessary?

2 Posts
Just changed mine last week. Ran into the problem of the bolts hitting the strut spring.

Wasn't sure if I could lower the strut without it decompressing (I did not find this great write up until later) so only loosened it but had to really struggle prying the strut spring to get the bolts out then back in. I saw that you lowered the car to get some weight on the wheel before tightening the control arm bolts to align it. I did not know to do that either and the car is pulling to one side so need to now do this to get it straight. Its 5 friggin degrees out but got to get it done.

Wish I read this great write up sooner. Thanks for this detailed write up.

I could not drop the strut since I did not have the tie rod end removed as in the photo, didn't want to risk ruining the tie rod end so I fought my way thru it. I finally realized I could cut off the extra length of the long UCA bolts and then chamfer and radius the bolt ends and was then able to get them in easier.
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