I didn't read all the replies, so I apologize if it was already stated


Did you happen to tighten the suspension bolts when the vehicle was still in the air ?


The bushing material will bind badly and cause some pretty crazy results at times. Not saying this is what happened to you, but I could see it putting a serious bind on parts. (I have seen it)

I haven't got the new bars installed yet as I'm picking up new hardware tomorrow morning.

Not an issue with the aftermarket poly bushings he has/had, as the inner sleeve is not connected to the outer and can rotate freely besides the drag of the poly bushing. Factory style bonded rubber bushings should absolutely be secured at ride height to avoid undue stress and tearing.

Any chance we can get some high res, well lit, images of the shear area of the UCAs once they are replaced?

Pretty sure I'm running the same bushings in my rear control arms, but only have about 15k miles under relatively mild conditions for my normal use. As mentioned previously in this thread, they obviously don't provide the same torsional flex of the stock rubber bushings, which would likely end up in the failure mode you have experienced

[QUOTE=Jeremy556;3765752]
Any chance we can get some high res, well lit, images of the shear area of the UCAs once they are replaced?

Jeremy, I'm happy to take more pics. Did you see the ones on the previous page? If so give me an idea what more you're looking for.

@Jeremy556




How's this look:

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The new joints are narrower than stock, I assume I'll be needing some washers to take up the gap? I can't imagine not having them in there

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Awesome, thanks. Hopefully some people that are knowledgeable might be able to shed some insight on the failure by looking at the break. It looks like one broke a while before the other with more rust on the broken area.

FWIW - It's very likely the result of the bushings. Poly bushings are not an upgrade in many cases and are not appropriate for the rear control arms. The rear control arms require more complex motion than a simple hinge joint like the front suspension. The ends need to both hinge around the center bolt but also twist axially as the link rotates and flex out of alignment as them move through the various suspension motions.

The flex out of alignment with the bushing pivot bolt is probably what caused this failure. Because the bushing wouldn't flex enough to accommodate the angles needed, the solid rod was bending at the top of the weld bead. That's where the load would be maximum and there's a stress riser. So most likely that's where you started to get metal fatigue after repeated bends, just like breaking a paperclip. And eventually it failed.

Fortunately it sounds like it wasn't on the highway in an emergency maneuver or something like that.

Looks like you have some replacements. I would put some washers in or you may be able to collapse the brackets enough to tighten up. I would not let them float loose on the collar of the through bolt.


Good luck.

You can see some of the classic metal fatigue in those ends, although it's hard without a bit more resolution than you end up with over the forum. There are pretty clear progression zones and then an area of fracture when it broke completely.





I think an engineer would call this a "high cycle low stress fatigue fracture". But I'm not an engineer. So I call it a paperclip break. The main takeaway is that it wasn't from hitting something hard. It was from lots of small back and forth bending over time where the poly bushing wouldn't flex enough and resulted in the shaft bending back and forth.

If it were a result of an instant impact where it pulled so hard on the end that it ripped apart it would look more like this (ductile fracture):

[QUOTE=Jetboy;3765892]FWIW - It's very likely the result of the bushings. Poly bushings are not an upgrade in many cases and are not appropriate for the rear control arms. The rear control arms require more complex motion than a simple hinge joint like the front suspension. The ends need to both hinge around the center bolt but also twist axially as the link rotates and flex out of alignment as them move through the various suspension motions.


Jetboy, as always thank you for your thorough reply! That makes sense and I'm not arguing at all. But.... if the bushings are the issue and these bushing seem to be a relatively common "upgrade" to the rear suspension. Why is this the only instance I've seen of the upper rear control arms failing?
My bad luck? (That actually makes sense, I am a walking perfect storm) I've run them longer than others? Maybe. (I looked it up I installed them almost exactly 3 years ago, November 2019. about 40,000 miles) It seems really odd to me

I got the arm installed today. Yes that's right @honda250xtitan you got your wish. Only the passenger side arm installed. However, that wasn't my intent initially. My local Toyota dealer only got me one set of hardware so I could only do one, and I need the truck. I may install the second one later. I did install 2 washers on each joint to take up the slop. Took a test drive and she's running great! Thanks to everyone especially @MStudt for getting these to me on the fly.

Mike these are really well made and really competitive in price. I'd recommend them to anyone who's interested. I'll report back as time goes on regarding performance and maintenance.

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Thank you for the business! I'll have to look into why these are narrower than yours since they match the width on my 2019.

Mike

[QUOTE=comtn4x4;3765914]
I think most people who put them in don't cycle the suspension very far or very often. If you have extended travel rear shocks, that would also add to it. Most of the damage will occur when the suspension is fully articulated. You can probably go lots of highway miles and never have an issue. It just boils down to number of cycles and the amount of deflection. So... take it easy, spend more time on the highways. And you'll be good to go! :P

You are 100% correct.
The inner shaft of the heim should be torqued solid to the mounts, so use whatever (washers, tubing) to make a snug fit and then torque the thru bolt properly. The inner should not move at all.

[QUOTE=Jetboy;3765928]
Yes I do have extended travel shocks.

Lol, more highway? Nah just more trips to the mall.

lol. so hows it feel with just one? i've considered going this route even though i feel like the rear end works pretty well with all stock joints and toytec springs/king shocks/bumps/kdss switched off.