When to change rear control arms?

[UniqueTII]

Hey gang. I have a 2015 XL 4WD with standard suspension and 145K on the clock. I've been frustrated with how sloppy the handling has been, even with 5100s all the way around and 38psi in my tires. I recently went through the whole suspension and steering to see if anything was worn but didn't find much of a smoking gun, although I noticed that there was a bit of play in the rear control arm bushings. Is there a good way to tell what normal deflection is for these rubber bushings and when they're worn enough to replace? Should I just swap them out due to mileage?

 

[ExplorerTom]

I’d swap them.

And get an alignment.

 

[UniqueTII]

I’d swap them.

And get an alignment.

Seems like a safe bet, thanks!

 

[Fastcar]

If there is slop in them change them. Put a big track bar on it. Then align.

 

[2011EL]

You're not alone with being frustrated at the sloppy suspension. I have a 2011 with 91k miles and it handles like crap. I just replaced the springs and shocks/struts on all 4 wheels along with the sway bar bushings and stab link bars. That helped quite a bit, but it's still loose. Not sure if the next step is to replace the upper/lower control arms all around. Are there any other bushings I should be aware of that would affect ride quality?

 

[ExplorerTom]

Dang. I’ve got 122k miles on my 2014 and I think it handles great. And I used to do some autox, so I’m not oblivious to a poor handling vehicle.

 

[mjp2]

You're not alone with being frustrated at the sloppy suspension. I have a 2011 with 91k miles and it handles like crap. I just replaced the springs and shocks/struts on all 4 wheels along with the sway bar bushings and stab link bars. That helped quite a bit, but it's still loose. Not sure if the next step is to replace the upper/lower control arms all around. Are there any other bushings I should be aware of that would affect ride quality?

I bolded issues I found so you're not dealing with a wall of text.

I just wrapped up a complete teardown/rebuild on my 2010 at 187k miles. I had a front end clunk and the truck didn't feel as tight as it once did so I replaced anything that had a ball joint or bushing.

Ball joints on the front LCAs were pretty loose. I had to cut off the LCAs as they were rusted in place. I'd previously replaced the UCAs and they were still in good shape.

Tie rods were in better shape than I expected -- I would have run the original outers if I hadn't already bought replacements. The inner tie rod on one side was showing signs of wear and was more loose than ideal so they were both replaced.

Rear LCAs were still in good shape but I replaced them anyway since I'd already bought the parts. The lower rear shock mounting bolts were in terrible shape (rust like crazy) so they got replaced.

I pulled the rear knuckles and checked all the ball joints. Most were in good shape but the rear upper control arms were crazy loose. I could freely spin the ball joint between my thumb and index finger on both sides. Definitely worth checking those for wear. They're easy to and cheap to replace.

Replacing your sway bar end links and bushings were a good call. Cheap and easy.

What shocks did you go with? I installed a set of Bilstein 5100s in the rear with my custom coils (900lb) and it rides nice. The Rancho quick lifts were leaking so anything new would have been an improvement there.

If you have any lift you'd likely benefit from a front alignment kit to get the camber in spec.

It's always worth mentioning tires. I run E rated tires at 50 psi. It's firm but the truck tows happily.

How are your wheel bearings? Even the slightest slop there gets amplified.

 

[2011EL]

@mjp2 - Thanks for the detailed response! I guess I'll need to take a more in-depth look at the control arms as well as the tie-rods.

I went with the KYB Strut-Plus assembly for the front and rear. I honestly didn't want to mess with trying to assemble the springs as that scares the crap out of me. My shop teacher waaaayy back in high school told us repeatedly how dangerous springs were if you weren't careful and shared horror stories. They still sit with me 30 years later. So, the pre-assembled units were an easy sell for me. I don't think they're as firm as I'd prefer, but they're way better than the old ones.

 

[Adieu]

Anything that has any play whatsoever should go if you have the money and want to make an effort.

New control arms are stiff AF.

For good smooth ride shocks at reasonable prices, Monroe are best. I had a Navigator L with those for a couple years, rode much smoother than Fords or Ranchos.

PS don't toss your old shocks if you still have them. KYB uses different parts so you can't swap it back to Motorcraft or go Bilstein if you decide to buy shocks alone.

 

[mjp2]

PS don't toss your old shocks if you still have them. KYB uses different parts so you can't swap it back to Motorcraft or go Bilstein if you decide to buy shocks alone.

That PS is HUGE. I tossed my stock stuff when swapping to Ranchos, only to have to buy new Ford shocks later so I could cut them up and scrounge the lower spring seats and spring isolators to install on my Bilsteins.