Johnny Joint grease—an experiment

Just like teflon fry pans. Great when new but crap in the long run. I'll stick with cast iron that re-seasons itself every time it's used. It'd be funny to see how a seasoned JJ ball performs. Just don't let the wife catch you!

If you want a teflon rod end they make those, but they aren't rebuildable.
Keep your wife happy and season in a gas grill.

I don’t think coatings are the answer other than to increase corrosion resistance. The problem is really how do you these certain kinds of earth from attacking the lubricant. Ideally some kind of seal/shield would be the answer but then the question becomes how?
 
You likely know a guy within arm's reach who could whip you out a set of 8 lower balls in 400C in not much time. That is certainly an experiment I would try if I lived where my parts rusted like that. I'd also try a bead blasted finish on half of them versus smooth to see if that holds grease better.
If I start making centering balls, I'm going the whole way and designing something that is greasable without disassembly.

The zinc chromate plating should help. I'll run that and see how much time it buys me, or if the joint is going to attract enough dirt to wear it out quickly.
 
Keep your wife happy and season in a gas grill.

I don’t think coatings are the answer other than to increase corrosion resistance. The problem is really how do you these certain kinds of earth from attacking the lubricant. Ideally some kind of seal/shield would be the answer but then the question becomes how?
Just like you do in ground engaging construction equipment. Provide a grease location where the grease can flow through and push the dirt and contaminants out. The trick is keeping a tight joint while still allowing the grease to get in there.
 
Spicer calls it "Glidecote" in their literature. I remember reading that it is some version of nylon/Teflon. @Shawn at Tom Wood's may know perhaps?
I have been told for years that Teflon is part of the recipe but I can't actually find any verification in any of Dana/Spicer's literature where they say exactly what it is. They just reference it as a feature and with no real explanation as to what it is made of. I did find a way old press release from 1998 in which they say it is nylon. You can find that press release here https://dana.mediaroom.com/index.php?s=26450&item=69594&mobile=No. Ctrl F to find search and find the word glidecoat. In this document from 24 years ago they say nylon. I don't think it is pure 100 percent nylon but I also don't know.

Now on to the reason the glidecoat works, in my opinion at least. The glidecoat allows for a much tighter fit between the slip yoke and spline stub than bare steel on bare steel. With bare steel you have to leave a little looser fitment so the parts don't seize together. This will result in some wiggle which will result in high speed drive shaft vibrations. The glidecoat however can be a real tight fit because it can compress a little if there's a little bump or a part that is a couple thousandths of an inch off. I kind of think of it as a bushing between the spline and slip yoke which serves the purpose of facilitating a tighter fit between the slip yoke and spline stub. I also think it reduces friction but grease is the key component to reduce friction.

Glidecoat sometimes flakes off but it is not common. Usually it is a result of friction and heat (probably caused by the friction). Sometimes it could be a result of a defect in the adhesion and application process of the glidecoat though this is very rare. In the instances where someone's spline is trashed because the glidecoat is flaked off the irony is that if the glide coat wasn't there the spline would probably be fused to the slip yoke instead, the end result is no better of a situation to be in. It isn't a perfect product, nothing is, but in my opinion it is WAY better than bare steel splines.

By the way, I didn't read this whole thread, just skimmed through and am replying only to the question for which I was tagged. I don't know exactly how this pertains to the underlying questions of the thread but hopefully my reply is useful.
 
  • Like
Reactions: psrivats
If I start making centering balls, I'm going the whole way and designing something that is greasable without disassembly.

The zinc chromate plating should help. I'll run that and see how much time it buys me, or if the joint is going to attract enough dirt to wear it out quickly.
The greaseable bolts actually worked reasonably well. The biggest issue is how much squish the races exert on the grease interface. The better way is with a sealed bolt, drilled, and then the one piece races they have for the billet joints. Something, anything that keeps the grease away from the inside of the barrel.
 
The greaseable bolts actually worked reasonably well. The biggest issue is how much squish the races exert on the grease interface. The better way is with a sealed bolt, drilled, and then the one piece races they have for the billet joints. Something, anything that keeps the grease away from the inside of the barrel.
I tried greasing through the bolt too, but I was just on the workbench, so the bolt was just being held in approximately the right position by hand. I did get some grease into the joint...but again, its only going to the center of the ball. The compression of the snap ring prevents the grease from getting between the race and the ball...And if you go too crazy, yeah, you end up getting the OD of the race all sloppy. What I haven't tried is greasing through the bolt and then running it for a bit to see if the ball will carry some of the grease into the race. I would imagine, based on what I've found so far, that the race, under compression, works a bit like a wiper and the grease is wiped away. That would be why every used ball I've ever seen has that dark ring around the center.

Since the races are relatively cheap...I might try to cut some grease grooves in a couple and RTV the openings to prevent it from moving through from the race/ball interface to the housing...

I gotta be able to grease these easier than tearing them apart after every trip...it REALLY sucks.
 
I bought a brand new RJ track bar and could not get the JJs to take grease before installing it.

I called RJ and asked about greasing JJs, specifically their track bar. Those JJs are designed with a one-piece race/bushing. As far as I know, you can't separate the ball from the race/bushing on these. The RJ rep said to remove the zerk fitting and make sure the hole in the race is lined up with the zerk fitting. If it isn't, just drill through the rubber race so when you apply grease, it makes it in to the ball.

My actual experience was that it basically would not take grease, even on the work bench, with the holes aligned. Too tight with a brand new TB. So I clamped a JJ ball in my bench vise with the TB still fully assembled. Then I rotated the TB in all directions, which seem to eventually get some grease on the ball and start to free up the joint. It took several iterations of adding a tiny amount of grease and moving the TB around to get the joint freed up and feeling like it's properly lubed. Before bench greasing, the joint was super tight and resistant to movement.

This is just my experience as another data point. YMMV
 
  • Like
Reactions: freedom_in_4low
Here's a brand new JJ I took apart to check the grease in. As I've seen in most I've opened up before, there's very little grease from RockJock. Ignore the little bit of red on the ends of the ball, that's just old grease in my assembly tool.

PXL_20221001_031652712.jpg
 
  • Like
Reactions: ranger101
Here’s what they look like after 10yrs of neglect and not greasing them. You can see the grease has dried out and stuck to the ball. What I thought would be pitted and rusty, actually cleaned up very well. I greased the bushings and the ball before reassembly and let the extra grease shoot out and wiped the excess away. I did not try shooting grease in them but I made sure the holes were lined up in case I ever needed to do so. Everything was assembled using STP Moly-Ep grease.

8412B7D5-A33E-4109-B44D-B07E965A6B21.jpeg


3E159A8E-AD9C-4916-B3B7-135E8E86DCE4.jpeg


781A8077-741F-4D02-A6EC-48B42FE95E29.jpeg


DD6539C5-EA32-4138-9249-0DACAD3A5B1D.jpeg
 
Here's a brand new JJ I took apart to check the grease in. As I've seen in most I've opened up before, there's very little grease from RockJock. Ignore the little bit of red on the ends of the ball, that's just old grease in my assembly tool.

View attachment 363465

I recently purchased all 16 joints for some home brewed control I made. Before installing I took every joint apart, cleaned the little bit of factory grease out then used the cv2 to reassembled. I think 3 of the smaller joints had enough grease I would have been comfortable with. All the others were nearly dry. Glad I had read that from all the folks here!

3942D236-AFFD-4D3A-9407-F04D4A6CD1F2.jpeg
 
Mining the archives here


Any updates folks?

Sorry not an update on clay dust resilience but I greased all 11 of my two year old JJ’s yesterday for the first time. I’ll echo what others have discovered—they were probably way under greased from the factory. The bigger ones were all so dry and seized (except for frame side front track bar) that I could hardly move them with a long screwdriver and vice. Btw these have been in California the whole time. I cleaned them thoroughly and used a dremel with a brass wire wheel to remove the polyurethane that was stuck to the balls. After liberally applying redline cv2 I was amazed at how easily I could move them even by hand. I swear I can even tell a difference in how the whole Jeep rides now. Everything feels much more free.

352D6300-2B90-41AD-9F46-D4B8CEAA4C9D.jpeg
 
Isn't that chainlube for bicycles? I have a tube of it for that use...kinda thin for putting in a Johnny Joint

I was told it was developed by Boeing for helicopters as a waterproof lube and rust inhibitor. I think for the rotors but it was along time ago. I’ve always used the spray.
 
Did my annual PM on my joints today. I am going to keep using the energy suspension grease. It doesn’t break down as much in the clay as the redline does. It cleans up pretty easily with a shot of WD-40 too. All of my joints were still moving, though some of them were pretty dry.

EC66E2D2-BD4A-4F6B-BA5B-813F1CA22B6C.jpeg


Others were Ok

BD0ACA10-979B-4242-9CC1-EFC083B17BCC.jpeg


This go round, I put grease grooves in the surface of the races. I had done one of them earlier and I could see where it keep more grease in contact with the ball. They are all done now…another variable is the amount of grease that I apply. I made sure to get enough in today to need to clean the squeeze out off

Here are the grease grooves

9FDDFD6B-F7E3-4D7B-AECA-40528E282219.jpeg


Honestly, I have 8 or so hours into this today. I’m so over it. There has got to be a better way or joint out there.
 
Thanks for the update! Curious to see how the grooves affect it. I don't blame you for wanting to try something else either, pain in the butt to break down and clean all the joints on a rig at once.

I wonder how the Summit Machine joints are.
 
Is F5 available in a grease gun format? I would think those grooves or something similar would make it so you could actually pump grease into the joint.

I haven't done mine nearly as much as you have but I just don't consider once a year disassembly to be a reasonable tradeoff for the mileage and wheeling I do. I'm seriously considering trying the RK Adventure series as soon as they become available to buy individually, assuming I can get them retrofit onto my arms. If not, I won't entirely dismiss a set of arms, either.
 
  • Like
Reactions: Wildman
Is F5 available in a grease gun format? I would think those grooves or something similar would make it so you could actually pump grease into the joint.

I haven't done mine nearly as much as you have but I just don't consider once a year disassembly to be a reasonable tradeoff for the mileage and wheeling I do. I'm seriously considering trying the RK Adventure series as soon as they become available to buy individually, assuming I can get them retrofit onto my arms. If not, I won't entirely dismiss a set of arms, either.

I’ve not seen it in a gun format, but I haven’t really looked either. I’ll have to look at the adventure series. Not familiar with that one.

They grooves are part of the solution I think. I’m still kicking around some idea in my head to make the grease go where I want it, and not where I don’t. For kicks and giggles, I tried squirting some grease into the housing zerk today on the bench. The castlations must have been lined up correctly, and the joint took grease easily. However, it flowed through the bushings, into the joint and right straight through the ball to the bolt hole. That ain’t going to work.