Has anyone broke one of these yet? (Rear Lower Control Arm Endlink Tab)

[Darth_Emma]

Well done, PQ. Thanks for sharing.

It's times like these when I'm glad I have a shop do mine. I could never do this by myself. I applaud all of you who are capable and do these sorts of jobs yourselves. I also applaud the shops who are doing these jobs for those of us who cannot.

[GTAHVIT]

Cool!

[LightningSS]

PQ: "As it turns out, when the finish is worn away, there IS a joint here. Can’t imagine why but I confirmed it on both arms. The coating disguises it but it’s definitely there. THIS IS NOT A CRACK. It’s an absolutely PERFECT joint. WAY to perfectly straight and true to be a crack."

This cannot be right. Is the "joint" welded? Somebody needs to talk to GM to understand this. I am not an automotive engineer, but I am an engineer in the aviation business and we design tierod/clevis setups everyday. I cannot possibly imagine this is an intentional design.

The CAD model that Pfadt analyzed didn't show this "crack." Maybe they can talk to GM (or whoever fabbed those after-market parts). Per the red in the FEM analysis by Pfadt this "joint" is at the point of highest load (obviously) and you would never want a joint of any kind at this location.

[JusticePete]

Originally Posted by PQ

Ok, last night I replaced the LCA and puet Pedders end links and sub-frame bushing inserts on the car. I'll do the CA bushings today.

As you can see, it’s NOT a good idea to break one of these. The end link was completely outside of the LCA and had separated the whole ball joint.
Attachment 220220
Attachment 220221

Here you can see material from the LCA bracket between the end link nut.

Attachment 220222


Another pic of the damage from the top. Is it my imagination, or does the new arm bracket look a tad thicker?
Attachment 220223


More damage. You can clearly see how it broke through.

Attachment 220224
Attachment 220225


The ball broke clean from the assembly. Lol

Attachment 220226


No doubt this is tight. LMAO, I torque this with my body weight pretty much.

Attachment 220227


Here you can see where my old end link had come lose before and I moved it to the inside. (stiffest) And yes I moved the other side then as well. Lol

Attachment 220228

I attached the Pedders end link before I installed the LCA.

Attachment 220229


My professional work area.


Attachment 220231

I set the end links to the shortest setting possible. The set nuts could be tighter but I did the best I could. They like to separate on the other one when tightening the first one.

Attachment 220232


As it turns out, when the finish is worn away, there IS a joint here. Can’t imagine why but I confirmed it on both arms. The coating disguises it but it’s definitely there. THIS IS NOT A CRACK. It’s an absolutely PERFECT joint. WAY to perfectly straight and true to be a crack.


Attachment 220233

Pedders most definitely more ‘Robust’ as Pete put it.

Attachment 220234


Ok, so inspect my work………. Lol

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Attachment 220236

Front sub-frame insert.

Attachment 220237


Rear sub-frame insert. See that pin at the top? That was a BITCH to get to go back right. The struts were not wanting to align with the LCAs and the front cradle joint was up so I had to wedge something between them to hold it down to balance it backward and zip tie the struts to a position in the LCAs to get them to guide in place………… OMG, that was a pain.

Attachment 220238
Attachment 220239

Excellant post.

In this side picture you can see how much material was worn away by comparing the size of the hole in the old arm to the new arm.



That aside....

PQ welcome to the PEDDERS NATION!

[PQ]

Originally Posted by LightningSS

This cannot be right. Is the "joint" welded? Somebody needs to talk to GM to understand this. I am not an automotive engineer, but I am an engineer in the aviation business and we design tierod/clevis setups everyday. I cannot possibly imagine this is an intentional design.

The CAD model that Pfadt analyzed didn't show this "crack." Maybe they can talk to GM (or whoever fabbed those after-market parts). Per the red in the FEM analysis by Pfadt this "joint" is at the point of highest load (obviously) and you would never want a joint of any kind at this location.

Beats me. The 'joint' (if that's what you'd call it) PERFECT. I looked at it, studied it, couln't get close enough to get a good pic, but I don't know what else to think.

Originally Posted by Darth_Emma

Well done, PQ. Thanks for sharing.

It's times like these when I'm glad I have a shop do mine. I could never do this by myself. I applaud all of you who are capable and do these sorts of jobs yourselves. I also applaud the shops who are doing these jobs for those of us who cannot.

It's FUN..........

Originally Posted by JusticePete

hat aside....

PQ welcome to the PEDDERS NATION!

[Redemption]

I have a feeling that this "joint" has to do with the way that piece is formed. Lots of bends in that steel. Maybe it was designed as the stress release point, to avoid the metal from cracking while being bent.

I dunno, I'm no engineer!

Jason

[PQ]

I'd love to know.

[GTAHVIT]

Originally Posted by JusticePete

Excellant post.

In this side picture you can see how much material was worn away by comparing the size of the hole in the old arm to the new arm.



That aside....

PQ welcome to the PEDDERS NATION!

Pete, I'm confused.

in one of Randy's pics he shows a piece of the mount still attached to the endlink bolt. which is obviously what was in the whole before the mount failed.

so I just want to be clear for my own understanding. The hole that is there now on failed LCA is due to the material that was removed when the mount failed.

If I understand you correctly ... that ring of material that stayed on the endlink is due to the endlink not being tight enough and it weakened that ring enough to be pulled from the mount???

Do I have all that right????

[Darth_Emma]

What knucklehead asked... ^^^

It seems a piece of the LCA is trapped by the nut and washer. Wouldn't that mean the nut was tight?

Originally Posted by PQ

Here you can see material from the LCA bracket between the end link nut.

[Huggerorange73]

Originally Posted by GTAHVIT

Pete, I'm confused.

in one of Randy's pics he shows a piece of the mount still attached to the endlink bolt. which is obviously what was in the whole before the mount failed.

so I just want to be clear for my own understanding. The hole that is there now on failed LCA is due to the material that was removed when the mount failed.

If I understand you correctly ... that ring of material that stayed on the endlink is due to the endlink not being tight enough and it weakened that ring enough to be pulled from the mount???

Do I have all that right????

Did you ever keep bending a thin piece of sheet metal back and forth? The fatigue on the metal eventually snaps the sheet in half.

I'm pretty sure the same concept applies here, except a loose end link on 2 ton car's control arm takes the place of your hands and the sheet metal.

[Camaro21]

I checked mine today when I was swapping out the rear tires to put on my DR's and Mine are fine!! I will keep an eye on them though..

[GTAHVIT]

Originally Posted by Huggerorange73

Did you ever keep bending a thin piece of sheet metal back and forth? The fatigue on the metal eventually snaps the sheet in half.

I'm pretty sure the same concept applies here, except a loose end link on 2 ton car's control arm takes the place of your hands and the sheet metal.

That's exactly what I was thinking.. I just wanted to be clear on why the whole is so big on the failed piece.

[JusticePete]

I do believe that 'tab' is the missing portion of the arm. If PQ can chuck the ball in a vice we could see exactly what remains. Huggerorange73 is on the right track with his post. There is another possibility as well. With the damage to the endlink and the arm it is possible there was more than just a loose endlink nut. I am thinking that some odd combination of coil compression with the geometry of the arm, sway bar and endlink resulted in a point of contact, a bind causing the dual failure. The ball joint could also have been separated after the failure, but once loose??? There are almost endless possibilities.

Here is what I do KNOW.

1. The ZETA II Chassis TEAM built a great product.
2. From the day we started on the ZETA and then ZETA II Pedders range we knew that an over size bar had to be carefully mounted to prevent tab failure.
3. Back-plating with hardened washers distributes the load and they are available right now.
4. The mounting point for the ZL1 bar is further out toward the knuckle. This means it will operate more efficiently than the current arm. Put another way, the ZL1 Pedders rear bar will be smaller.

Speculation...

My guess is the ZL1 arms will fit an SS as an off the shelf from GM solution.

PQ,

If you still have the ball joint and failed arm. Let me know as I would like to have it for a failure analysis.

[GTAHVIT]

Wheel hop???