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Help Needed with Upper Control Arm Ball Joints

braydun

FBBO Gold Member
FBBO Gold Member
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Hi, Members.

I hit a snag earlier today and am looking for help/guidance.

After removing the original upper control arms from my 69 GTX, I had them cleaned, powder coated, and new bushings pressed in. Went to install the new ball joints after bolting the control arms to the shock tower and wasn't able to tighten the ball joint, it just spun in the socket. After removing and inspecting more closely, it appears that the threads on the original control arm are stripped.

Has anybody experienced this and is there any way to easily repair? Or am I purchasing a new set of upper control arms?

Thanks,

Brent

Screenshot 2026-03-22 142136.png


Screenshot 2026-03-22 142127.png
 
Install the ball joint and tighten it until right before it strips and put four GOOD spot welds on it. People have done it for decades.

Or

Take some steel stock like in a feeler guage. .005 is what is typically used. Put it in place slowly tighten the ball joint in it will shape the shim stock into the threads and almost be like new.
 
The threads in those arms don't look like normal threads when fresh.
 
If they are stripped so a ball joint wont tighten they are junk. Just make sure the ball joints are not cheap and made undersize.
 
We've put a couple of good blobs of weld from the old tombstone Lincoln on many of daily drivers over the years so guys could make it to work tomorrow. Never had one fail
 
Install the ball joint and tighten it until right before it strips and put four GOOD spot welds on it. People have done it for decades.

Or

Take some steel stock like in a feeler guage. .005 is what is typically used. Put it in place slowly tighten the ball joint in it will shape the shim stock into the threads and almost be like new.
Great advice. Thanks
 
Mystery solved on this one. PSA for those who don't know. The threads on the upper control arms were not stripped, it had to do with the Moog ball joints. I ordered new Moog K772 ball joints from Summit to replace the originals. Turns out these Moog ball joints are about 1/16 inch too small. So they don't tightly seat in the upper control arm. I've heard people mention that Moog parts are junk nowadays, this is further proof. I ordered Proforged 101-10126 ball joints, they fit perfectly. Thanks
 
Mystery solved on this one. PSA for those who don't know. The threads on the upper control arms were not stripped, it had to do with the Moog ball joints. I ordered new Moog K772 ball joints from Summit to replace the originals. Turns out these Moog ball joints are about 1/16 inch too small. So they don't tightly seat in the upper control arm. I've heard people mention that Moog parts are junk nowadays, this is further proof. I ordered Proforged 101-10126 ball joints, they fit perfectly. Thanks
#4 above mentioned that fact.
 
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