Upper threaded ball joint is too large

[E5charger]

I purchased Proforged upper ball joints for my 74 Charger and they are too large. I can start the threads on the old one by hand, but then need the socket to go further. The new one won't reach the threads. I used my caliper to measure both to see how much larger the new one is. At the top of the taper, the old one is 1.8050 and the new is 1.8265. I then measured in the middle of the threads and the old is 1.8405 while the new is 1.8440. I have read someone pressed them in up to the threads and used an impact gun to drive them on. I realize the uppers can be self tapping, but I'm concerned this could screw up my control arms. They are super nice originals. I wonder if a different brand would be closer in size. Anyone have some they haven't installed and could measure for me? Thanks!

 

[pnora]

They can be a bugger. Sometimes I use a bit of heat on the arm. Just enough to help it ease in. Wire wheel or sandblast the hole can also help. Are the arms in the car or on the bench?

 

[E5charger]

The arms are on the restored K-frame. I could bolt the k-frame to the car if I need the leverage. I'm concerned about cracking the control arm trying to force them in. Also cross threading them! I wonder if I would be better off trying Moog or ?.

 

[Beekeeper]

The upper ball joints have cutter threads on them. When they were originally installed the upper A arm opening wasn’t threaded so replacements tend to be a bit oversize so they cut deeper threads.

 

[WileERobby]

Mopar UCA ball joints = almost always a bitch. I'll never forget the first time I did one of those jobs back in the 70's. The old-timer in the garage gave me like a 4' pipe to use for leverage.

 

[PST]

The proforged as well as some of ours are similar to the Moog "problem solver" ball joints. Meaning they are slightly over-sized to compensate for control arms that have had multiple ball joints swapped out over the years. They are designed to take up wear in the control arm. So on a control arm that did not have many changed over the years they can very tight on the install.

James From
PST

 

[E5charger]

Hi James. You mentioned some of yours are slightly oversized. Do you have ball joints that are the same specs as the original Mopar ones and if so, where are they made? I'm 90% sure mine are original and didn't damage the threads when I removed them. Also, would my 1 7/8 socket fit your ball joints? Thanks for answering my post.

 

[PST]

I can get you some measurements in the morning when I am in the office. I will PM you the details.

Thanks
James From
PST

 

[YY1]

Have to disagree with the "self tapping" comment.

All the 73 and 74 threaded BJ and UCA's I've worked on had rounded profile, shallow threads.

They should start by hand and allow at least a couple turns before a torque multiplier is needed.

They are however, fairly easy to cross thread.

Having thm both super clean is crucial.

If they seat fully by hand, the UCA is almost certainly cracked.

I've never heard of stretched/worn threads on the UCA.

Can the OP clearly see the rounded profile threads?

IIRC in 74 there was a mid-production change to the press in style.

Could you be trying to thread into a press fit UCA?

I've actually heard of that more times than you'd think.
(As well as trying to press into a threaded UCA )

 

[E5charger]

The threads are definitely shallow, but I have read that NOS arms actually don't have threads and the ball joint cuts them. The service manual says to start the ball joint by hand if you are using the original control arm. So who knows. My upper control arm and original ball joint both have threads. The problem is, the new ball joint is too large and doesn't have enough taper to reach the threads of the upper control arm. So I am on the hunt for a ball joint that is the same spec as the original. It seems most are larger to take up the slop of worn control arms.

 

[Cranky]

I'm with YY1....smooth rounded threads on the ball joint are not cutter threads in my mind. They may force themselves in the the new control arms but they don't really cut anything but will roll out metal and will be difficult install without having a 3/4 drive impact. Also, I'd rather deal with ball joints that are too big than too small like what used to come from China! Those dang things would pretty much fall into place. My last front end job was two years ago and the owner brought me Shineese crap and I ended up tack welding them but they were better than the 1st set he had. My ball joint socket wouldn't fit the first set....and the part number on the box was for a B-body. Do 'A' body ball joints have smaller threads?

 

[E5charger]

James, from PST, has been super helpful. He actually took the time to measure their ball joints at multiple spots. The PST ball joints are very close to the original. Much better than what I have. Thanks James!