Check this NOW if you have a 2021 Bronco -- cracks on rear control arm upper brackets

[srick76]

This doesn't look like a terribly hard one to design, I'll look into it. It would be weld on which might turn off some people but this isn't a place for bolt on solutions.

I'll take two!

Sponsored

 

[srick76]

I can’t find Mitch Creek’s posts on IG.

It was a reel, or story whatever the heck they call them.

 

[srick76]

I have an EARLY '21 built in June 21, delivered in July.
Black Diamond, manual trans, tow package.
I was recently under if, putting on Sasquatch take offs. I know I'm open, and now that I see other's "cracks" I have to look more closely when I get home, I fear my passenger side has similar cracks. Been wheeling 3 times with it, the last was a medium level trail with some rock crawling. I'll update.

 

[LanceIto]

It was a reel, or story whatever the heck they call them.

 

[Bird Dog Off Road]

I saw it on Ticky Tok

 

[BroncoKing610]

Delivered Aug 21, OBX V6 4D w/ tow

 

[8421dave]

7/21 build, 4d wildtrak, tow pkg, no rear sway bar.
unboxed

 

[Big Boss]

21 Big Bend, build 11/15 open.

Looks like some rust there but don't see any cracks but it's also covered in snow and salt

 

[Finbox]

2023 Bronco Raptor Nov 2022 build date

 

[BigMeatsBronco]

Good thread @popo_patty. Interesting stuff. Some thoughts on how energy gets transferred through the rear links and into the end mounts that are cracking.

The oem bushings on the rear links are compliant in the sense that the material will deform (strain) allowing for motion and rotations and thereby providing some extra articulation from the “rigid” links. These deformations in the bushings allow for some of the shock energy from dynamic loading to be absorbed in the form of deformation or strain energy. This reduces the shock transfer to the frame but at the cost of articulation. The bushings need to deform under stress which limits compliance based on stiffness.

The fancy after market end links with Johnny joints allow for freedom of movement or rotation without much resisting stress. This enhances articulation but comes at the cost of limited strain energy absorption. The bushings are stiffer and allow for low friction sliding that produces no significant shear strain or deformation, only minimal compressive strains. And thus they usually transfer greater shock loads.

The metal on metal heim joints have virtually no compliance and don’t absorb any significant strain energy.

not saying the aftermarket end links are good or bad just how they transfer energy.

once again you see what I see, the metal joints cause MOST of this problem. Rubber or urethane joints have enough energy absorbed to protect the metal from FATIGUE, that is what is the #1 cause...FATIGUE.

 

[roboticsrob]

I wonder if the change to the box design coincided with the addition of rear sway bar end link brackets. The timing seems about right.

2 Doors don't get the rear sway bar (though I recall the 2 Door WT might actually have a rear sway bar with Hoss 3.0?), but it does stand to reason that an upgrade made to the 4 Door frame would also flow down to the 2 Door frame.

OP if you do end up letting your buddy weld it up, be careful if welding on your car. Even disconnecting the battery, a welder can still fry electrical components on modern vehicles.

Need to get the ground on the welder very close to the work area.

One of the guys I work with fried some components on his GMC recently when he was doing his exhaust and learned the hard way.

Unfortunately true, various modules are grounded to the chassis all over the place.

 

[TheKim]

Rust city!

@Ford Motor Company - recommendations?

 

[vrtical]

Here are the build date breaks for the 2.7. Don't know what physical changes were done but the first version was not quite two months 5/3/21-6-24-21.

All these people looking, there is a frame tag that would help narrow it down, but frames are pre-built way ahead of time so it could be old stock if Ford decided to use whatever is sent to the plant instead of stopping the use of the frame that was updated.

 

[EazyCheezy]

So far all 4 of us with cracks are modified with aftermarket, rear arms, 37's and we wheel hard and often. I'm still looking to see if unmodified 2021 Broncos have this crack but so far no.

BREAKING NEWS: Local man who modded his vehicle past factory spec and abuses it is shocked when shit starts breaking.

 

[userdude]

BREAKING NEWS: Local man who modded his vehicle past factory spec and abuses it is shocked when shit starts breaking.

In a sense, hot takes are always "breaking news" since the point of them is often to skew the purpose of a story told in a way that is sensational, moralizing and condescending. In that sense, couching a hot take as "breaking news" instead is simply moralizing and condescending without reviewing the total context of the discussion as it stands and weighing the outcome of the story in those who may be affected by the intended purpose of the story.

TLDR; nice hot take but this thread has a genuine purpose and I don't think @popo_patty intended it to be anything but helpful, even if the title and early commentary is a bit overheated.

Sponsored