I need to replace the upper control arm and ball joints onmy 1987 Dodge D100 truck. The new factoryMopar upper control arm that I got from the dealership is not threaded for theball joint. All of the upper ball jointsthat I have found at the auto parts stores are threaded, and the parts placesand the garage are saying that they never saw an unthreaded upper control arm. I checked with several Dodge dealerships tomake sure I had the correct part number and control arm and they gave me thesame info. The photos also show thecontrol as being unthread like the one I received. They even cross-referenced the Mopar upperball joint with aftermarket upper ball joints such as the Moog K778, and I havethe ball joints according to the numbers. So I am now confused.

I haven’t found much online regarding this issue. However I did read on another forum that thethread ball joint would be screwed into the unthreaded control arm and the balljoints threads would cut the threads into the control similar to self-tappingthreads. I have not been able to haveanyone that I have personally talked to be able to verify, that this is how theD100s control arms and ball joints went together. Could this be the case, because it looks likethis is the only way the setup will work? Any info would be appreciated. Thanks

 

How would the dealership go about putting a ball joint in the new arm?
They should know how its supposed to go together?

Dave

 

I was finally able to verify with two Dodge dealerships and a few forum members, that the threaded ball joints needed to be threaded into the unthreaded control arm so the ball joint threads could cut its own threads into the control arm. The truck is now back together, and just need to get the frontend realigned. It just seemed like Dodge would have threaded the control arm from factory, since it needed a threaded ball joint. So thanks again to all who contributed to finding the answer.