Haven an odd one to run past the brain trust here. I did a full truck suspense rebuild. Front upper arms are OEM from LR Direct in the UK. Lowers are Mevotech, which is one of the very few aftermarket brands I trust for suspension critical stuff. But in fairness I bought them because they were $50 on closeout at Rock. They have not been an issue at all. So when I saw an upper arm from Mevotech come up cheap, I grabbed it as a spare. I love to keep lots of spares!

Fast forward 40k miles. I have a bad strut. I get two new OEM Struts from LR Parts.net. Damn, what an improvement at 208k miles! But to my horror I found a ton of play when putting my passenger wheel on. 12/6 o'clock, assumed bearing. Nope. Upper ball joint was SHOT. I had a clunk and assumed sway bar links, even ordered a set.

So here is the issue. I pressed out the old ball joint and took the joint out of the new Mevotech arm. The issue is when I put the Mevotech into the OEM arm, the joint plopped right in! No press-fit at all. This is an issue because now the only thing holing the joint in place will be the circlip. Its job is more of a backup than to take constant abuse of the arm slamming between it and the joint cap. So something is not right. The Mevotech reads about 0.5mm smaller in diameter than the OEM. So in a pinch, I order the only one from Amazon with fast shipping. It is from CTR, which is OEM for Kia and the likes. Reputable but not a brand I used before. Well... it is smaller too. Larger than the Mevotech but still undersized. You can see below that if I press it in there wont be much bite, a millimeter or two at best. I took the OEM and set it in and you can see how much higher it sits. So for now I added some shims and pressed the CTR one in which helped a TON. Test drive and it has not moved. I do not plan to keep it in there though and I have two more ball joints coming. One is TRW and the other is API which is a re-boxing brand I have had great luck with.

Here is the flip side to this issue however. Like I said, I like to keep spares and take some with me on long cross-country trips where I bounce around mountain trails. So ball joints are something I bring. If I had put the entire Mevotech arm in instead of swapping the ball joint, I could have been in a position where its joint hole is way to small to take an OEM or other brand ball joint. Or like I am experiencing now, aftermarket ball joints simply not fitting properly. Apparently my neighbor ran into this situation a couple weeks ago where he damage an upper on trail and limped home to replace it - found the replacement was too small too!

So has anyone else ran across this issue? Its not like the uppers ball joints tend to fail a lot though. But what I would love is if someone has a true and proper OEM ball joint on hand and could measure it. I think mine was 42.5mm. The Mevotech was 42mm and the CTR is 42.25mm. I need batteries for my caliper to get exacting measurements, which I will do.

 

Did several rounds of measurements on the ball joints to be as accurate as possible with a fresh battery in my caliper. I cant measure the CTR which is installed (with shims).

OEM 42.53 - but its distorted a little, measures up to 42.6 across one side.
Mevotech 42.30 - first new one I installed and then removed
TRW 42.31 - new, not installed
API 42.32 - new, not installed
CTR ??.? - installed and in use

I think its obvious that spec is 42.3mm for the ball joint. But for some odd reason the newer OEM arms I have are out of spec or there was some odd revision. I really have no clue but I obviously will not be installing the joints that came today. I would have the same issue. I will measure the CTR also once removed. But the stainless cable tie shims are holding fine so far with my ventures around town. I have another OEM arm w/ball joint installed on order from LR Parts.net. I also ordered two ball joints. I will measure the ball joints, but I dont plan to remove the one on the new arm. I may be able to still measure it though.

 

Finally got a minute to dig mine out of my scrap pile from my 2006. I pressed new Lemforders into the factory arm with no issues. Same on my 07.

I don’t have any batteries for my caliper, but here’s the OEM upper.

 

Small update.My driver side has now failed. Same issue with a cracking boot and now I have a little grease getting out. On my last camp outing I noticed a knocking noise but only when I was driving slow and positing my rig at camp. Never really heard anything on the trails, oddly. So I opened the "OEM equipment" ball joints from LR Parts - which by the way are just Delphi! Go figure. They measure 42.5 which in fact closest to what I pulled out of the "OEM equipment" arm. So before I order yet another complete arm I will try a Delphi for fitment. Tend to think it will work. Never really did find out why there is this issue or if there was some change. I know there are subtle differences between an LR3 and LR4, but the upper arms I originally ordered were using an LR3 part number. And really the size difference is soooo small that I find it hard to believe it is an intentional design change.

 

I have read elsewhere of the issue with aftermarket arms and balljoints not fitting, i need to re-bush my uppers and lowers when i get a chance and i bought optimal brand bj's from Advanced factors so hoping they play nice with the genuine arms.
Still need to buy lower bj's so will get Lemforder.

 

Another update. Good news is the Delphi ones fit just fine. Bad news is that they *may* be longer than the others I installed. This created an issue. Installed on and it was pretty sloppy. No actual play that I could feel, but no resistance to articulation. I could not leave it like that. So out it came! The second one I did in a much slower manner. I would get it a short but and remove the press and inspect. I did this up to the end but on the final check I noticed the installer cup I used, really the only one to use, was not going up all the way to the arm and around the joint that was sticking through. That was because the spindle end was actually bottoming out in the installer cup! That cause the first joint to be pushed up into the top/crown grease area whatever and probably distorted things enough to allow the slop. So with the basic ball joint kit I had I needed to get creative for the last half millimeter just so the snap ring would fit right.

The installer cup tool thing that is not deep enough:





The creative combo needed to prevent the spindle from bottoming out:



Also a new trick on this upper ball joint job, cut the dang spindle. Just do it. Makes removal MUCH easier. What you do is use a large deep ring, like pictured above now sitting under the joint - use that on top with a cap to locate. Then one the spindle end use the other black cap thing and drive things home. That lower one WILL walk over one way and may frustrate you. Don't, just let it walk and tilt and just drive tihard it will pop out. Well as long as you remove the snap-ring! And keep in mind the torque spec on the ball joint is really low! I thought it was 68 or 72 - NOPE! I started to torque mine but stopped after I questioned it. It is only 52 foot pound which is not much. I think mine is around 65 when I stopped.... For that reason alone I may replace it yet again because I am paranoid.