This may should be in the "Stock" section, but I'm lifted, with 37's, and think that may be the cause. Anyway, is it possible/normal for a ball joint (if worn) to have up and down play, without having in and out play? In other words, I can lift my JK and grab the tire at the 12 and 6 o:clock position, and try to move it in and out, and can't feel any movement, but as I jack it up and let it down, I can watch the knuckle move up and down from the C, probably 1/16", at least. Is that "worn out", even though they don' have any in and out play in them? By the way, the ones I noticed the movement in first, was the uppers.

 

Radial (side-to-side) movement in the upper ball joint should not exceed 0.060" (1.5mm).

Axial (up and down) movement in the lower ball joint should not exceed 0.050" (1.25mm).


A dial indicator is the best instrument to measure ball joint play.

Jack the front tire off the ground.
Place a jack stand under the axle next to the jack.
Lower to put some weight on the jack stand.
Place a long pry bar under the tire, from the side.
Have someone pry the tire up and down while you watch the lower ball joint for up and down play.
Axial (up and down) movement in the lower ball joint should not exceed 0.050"

Have someone grab the tire at top and bottom to wiggle the top in and out while you watch the upper joint for side play.
Radial (side-to-side) movement in the upper ball joint should not exceed 0.060"

Even if the upper joint checks good, change both if the lower checks bad.

 

Thanks Ronjenx. I don't have a dial indicator, but like I said, vertical movement is at least 1/16 (0.0625) on the drivers side upper, so that's pretty much definitely out of spec., as 0.05 is 1/20th of an inch. I don't even know if a 20th would be easy to see. Mine could even be upwards of an 8th of an inch, but I don't think I'd go as far as to say that. It's definitely noticeable.

 

If you haven't seen it yet, check out this thread. It will show you why only side play is measured on the upper, and vertical play is measured on the lower.

https://www.jk-forum.com/forums/show...-Study-Results

 

Hmm, so the axial (up & down) movement in my uppers could be normal, then. Honestly, I didn't notice a lot of axial movement at the lowers, although I'm not sure if the uppers could move up and down without the lowers doing it too, as the knuckle is one large piece. If the top joint moves up and down, wouldn't the bottom have to me moving the same direction (up and down) to allow it?

 

And thanks for the link, I had not seen that. I'll lift it up again tomorrow, and get some help, and take a closer look at everything again.

 

Yes, the lower has to be moving up and down, too. The lower is the "master" ball joint. The upper one only stabilizes the knuckle.

 

That's what I figured. If I'm seeing axial movement in the upper, but no side to side, it's actually probably good, and the lower one is the bad one. Trust me, when they get replaced, they'll all get replaced, bad or not (uppers).

 

Yes. I always recommend both get changed while it's apart.