Lubricating the Steering Knuckles


Steering knuckle
This is a long-overdue Tech Tips page. How to lubricate the steering knuckles and the axle joints inside them has long been a popular question and a contentious issue on discussion forums. The information below, selected from several CJ-3B Bulletin Board discussions on the subject, covers what type of lubricant to use, some suggestions for specific brands, and tips for servicing the knuckles.

Perhaps the most important point is: the choice of lubricant depends partly on which of three types of axle universal joint you have inside the knuckle housing -- all three were used on the CJ-3B.

The empty knuckle is seen here with its connection to the steering system. -- Derek Redmond

Depends on what kind of axle joint is inside

Bob C. asked: I'm in process of putting 11" brakes on and did the kingpins also. Wondering what people are using for lube in the steering knuckles?

Red stepped up: This subject has reached the level of inflamed and passionate opinion on other sites. Views vary according to, well, they're all over the place. But here's what I've done with mine:

I have an M38A1. I post here on this site because it has a uniquely sensible approach to old Jeeps and because so many of the systems on A1s and 3Bs are similar. My Jeep has a Dana 25 front end with Bendix axle shafts. The military manual states to use #0 grease in the steering knuckle. This is essentially 2 levels lower viscosity than the typical #2 we all use for u-joints, steering, etc. Many if not most owners also use the #2 in the knuckle and I figured that should work fine if lube intervals are maintained, as the greases these days are uniformly superior to anything the manual writers had available in '54 (DOD of my A1).

Grease on Bendix axle jointBut I prefer the #0 for several reasons. First it's what the manual calls for. Second, it does not create what I think is called a "tunnel effect", where the #2 grease gets thrown against the wall of the knuckle and stays there and eventually deprives the axle shaft of grease. The #0 being less viscuous is thrown around the knuckle when the shaft turns (either in 4x4 mode or all the time if you are running a rig without lockout hubs) but returns to the axle shaft and keeps it largely immersed in the grease at all times (therefore, no tunnel effect).

By the way, I observed this "tunnel effect" in my A1 when I did the initial clean up and greasing not long after bringing it home. Not only was the grease not doing the axle shaft any good, there was no way it could have been lubing the top kingpin bearing either. Which brings me to the third reason I use the #0: when the axle shaft turns it throws the #0 all over the knuckle and serves to grease the top kingpin bearing as well. This won't happen with #2 grease -- it's just too thick to move that way and it's not supposed to be thrown off like that anyhow -- it's supposed to stick.

Now, many use the 140 weight and I can't say how that works. There is nothing better than immersion in oil for lubrication and if you can keep it from going past the seals, that would be the way to go. My concern there would be the loss of oil and questionable lubing of the top kingpin bearing. Also, there's the chance it could migrate towards the differential, though I can't say if that's a problem.

I also consider the intent of the designers of the Dana axles. The fill plug is large enough for a grease gun to fit in to it. It's at mid height on the knuckle, meaning that is the correct fill level. This alone indicates to me that the original intent was to have a more fluid grease in the knuckle than #2 grease, for #2 doesnt settle, as an oil or #0 does. Another design characteristic of the Dana knuckles, which I believe is under-appreciated, is that they are supposed to allow a certain amount of grease past the knuckle seals. If the grease is of a viscosity that will properly lube the bendix joint and the top kingpin bearing, then it will be lost past the seal to a certain point. It might be nice to have a clean axle housing, but it might also mean that the grease is so thick that it isn't doing its job inside the knuckle.

I use what's called "cornhead grease". It's a John Deere grease they use in combine type gearboxes ( called corn heads). it's a thixotropic grease meaning it won't leak out and adheres to moving parts, yet returns to level (as would an oil) when at rest. So far I haven't had any problems. The kingpin bearings are all new, and I keep a eye on them as well. Sounds odd, I know, but I did not feel that #2 grease was doing the proper job in the knuckle, so I went looking for the grease the manual called for. #0 isn't easy to find in small quantities (I had one outfit say I had to buy it in 5 gal buckets minimum, another place said minimum was a pallet!).

Rus Curtis: Red, I could not agree with you more. This is a VERY interesting topic that has a wide range of understanding, interpretation and opinions.

Bob, I think the direction you should pursue (the type lubricant to use) is dependant on which type joint you have.

I have two manuals. One for early model CJ-3Bs and one for late model CJ-3Bs.

The early manual, SM - 1002-R6, covers CJ-2A, CJ-3A, CJ-3B, CJ-5, CJ-6 and DJ-3A. The late manual, SM-1046, covers CJ-3B, CJ-5, CJ-5A, CJ-6, CJ-6A and DJ-5, DJ-6.

The early manual calls for No. 1 (Summer) and No. 0 (Winter). The late manual calls for SAE-140 for both Summer and Winter. Both manuals cover the CJ-3B but which lubricant is appropriate? Further reading uncovered that the two manuals differed in the M section that covers the Front Axle. The early manual discusses service for the Rzeppa joint, the Bendix joint and also the Spicer joint. The late manual only covers the Cardan Cross (Spicer) joint. The other two joints had been discontinued.

Axle U-joint types

This is the reason why I think there are different lubrications listed. The Rzeppa (pronounced "Zheppa" -- Derek) is a version of a Constant Velocity joint and modern CV joints use a special lubricant, not No. 2 grease. The Bendix is another version of an open knuckle. The Spicer joint is virtually closed so cannot benefit from a thicker lubricant.

I'm not saying that the two earlier knuckle designs can't be lubricated properly with SAE 140. However, I do question whether the Cardan (Spicer) can be lubricated by thicker No. 0 or No. 1 due to higher viscosity. I believe the later models using the Spicer list the SAE 140 lubricant as it's thin enough to penetrate the joint and actually do some good with the needle bearings (since they aren't external with a grease fitting like the propeller shafts -- Sect. L).

Oldtime commented: Realize that the information provided in the Service Manuals was usually superseded by that provided in the latest publications. The latest information provided for model CJ-3B designates the use of 140 weight gear lubricant as being correct. But that is a late recommendation to cover all axle shaft joints types, and is not specific to the type of joints that are in a particular axle assembly. The Bendix and Rzeppa joints are able to use different type of lubrication than the Spicer type joints. Those axles with Bendix or Rzeppa joints can use a thicker grease in lieu of the 140 wt. oil.

Service Manual diagram

The Spicer type joints will mandate the use of 140 weight gear oil. Spicer type axle shaft joints were not available before 1955. Neither will all post-1955 front axles be equipped with these Spicer joints. My point being to use a proper lubricant for your particular type of axle joints.

I suggest using the NLGI grease if we assume that your Jeep axles are equipped with Bendix or Rzeppa joints. The grease will be easier to keep sealed in and should do a better job on the associated kingpin bearings.

Greg: 1. How do I figure out what brand of knuckles I have? For example, what identifying parts on the outside distinguish a Bendix or Rezeppa from a Spicer? Or, do I have to go inside the knuckle to determine its maker?

Oldtime: You need to look inside to determine the axle shaft type. Study the figures in the Service Manual, then using a probelight / flashlight take a look inside the fill plug hole to determine the type of axle shaft joint.

Rus Curtis: No. 0 and No. 1 lubricant is not easy to find. This is why I believe so many have developed recipes for "knuckle pudding" to do the job. After all, the two ingredients -- axle grease and gear oil -- are readily available.

I agree that putting No. 2 grease in the knuckle is wrong. As pointed out, it would be pushed to the walls (tunnel) and stay clear of the moving parts. Therefore something thinner is needed to penetrate the joint as well as settle in the knuckle to partially cover the parts when not rotating.

That leaves kingpin bearings and leakage. Wheel bearings are no different from kingpin (tapered roller) bearings. However, the manual does not specify packing the kingpin bearings with grease like what is done on wheel bearings -- at least not that I could find. We know that packed bearings in the wheel do not lose their lubrication due to heat or spinning. We also know that filling those wheel hubs (when servicing the bearings) with grease is wrong as heat cannot dissipate - and there's no increase or added benefit in lubrication. Oldtime has pointed out that the kingpin bearings only move a little bit (back and forth) during steering. This is addressed in Section O, by confirming the angle of travel is only 23 to 29 degrees either way, depending on your joint type. The bearing will not spin completely. So will these kingpin bearings maintain lubrication if packed like a wheel bearing?

When the 3B (and other models) originally came with a drive flange vs. freewheel hubs, there was never an issue with kingpin bearings receiving lubrication from the spinning axle. With freewheel hubs, the front axle could sit for some time without spinning. I have packed my kingpin bearings and could argue that they will never run dry (since the grease will not drip out). However, the axle joint will need lubrication (so the knuckle can't be left dry) and the resulting splashing effect (when the axle spins) cannot be a bad thing for the kingpin bearings and while the splashing may dilute some of that packed grease, the resulting lubrication bath will keep the upper bearing lubricated.

Leakage has been addressed before and most that use the SAE 140 report it does not leak through. The thicker 0/1 grease should not have a leaking issue.

Servicing the knuckles

Leaking 90-weight oilGreg had been given some bad advice: I've found no consistent instructions regarding the proper lubricant to put in this steering knuckle. One manual I have says 140-weight gear oil, which NAPA said they didn't have and couldn't order.

Some very old and hard-crusted grease is inside. No grease or oil is getting to the smooth, polished metal surface, which I believe should be lubricated.

I asked the owner of a 4WD shop (when he told me my transmission leak was an engine oil leak, without touching or smelling the oil) what type of lubricant to use. He told me to put 80-90-weight gear oil in there. I did, and as you can see, it's leaking.

Daryl: Probably the most debated topic ever, dealing with Universal Jeeps. Straight 90 weight will not work, as you have found out. Most people make a thicker concoction by mixing grease and gear oil to resemble what was available 60 years ago as a 140 weight oil. Some specialty oil makers do have a ready made oil such as John Deere makes for agricultural gear boxes.

Greg: Great answer, just what I was seeking. What's been most surprising on having this Jeep since May is how wrong some declared experts can be. I couldn't figure out why he said 80-90 gear oil after he shoved his finger down in the Knuckle hole and came out with a greasy finger.

First question: Is there a way to drain out what I put in, or must I suck it out?

Second question: The grease that's currently in these knuckles is so hard, it doesn't and won't lubricate what it's supposed to lubricate: there is no, zero, lubricant on the surfaces that need lubrication. I've seen properly lubricated knuckles, and I don't have properly lubricated knuckles. I don't know how this mechanism works to know if I need to take something apart to clean out the hardened grease inside, so that lubrication can begin. The 80-90 gear oil is NOT getting to the surfaces that are supposed to be lubricated, even after a couple hundred miles of driving with that too-light fluid in there.

Knuckle disassembledOldtime: Suck the gear oil out or disassemble the hemisphere.

Rus Curtis: When you service your kingpin bearings you have to disassemble the knuckles. This will allow you to replace the seals (rubber and felt) on the "shiny" part as well as clean out the old grease -- no need to use a degreaser, just wipe out the junk with a paper towel and move on.

When you service the knuckle, part of it is to inspect the polished metal surface and remove scores or scratches with emery cloth. When the new seals are in place there is a layer of felt that keeps it clean. The SM states after driving in wet/ freezing weather, swing the wheels back and forth. This allows the felt to wipe the surface clean and avoid freezing. The SM also states if you store it for a period of time then coat with light grease to avoid rusting. Pretty simple.

Discussion and SM study lead me to conclude that if it is a later style cardan cross (Spicer) joint, then the (later published) SM says use 140wt. However, if your axles have the earlier Bendix joint, then that is more like a Constant Velocity (CV) type joint and the (earlier published) SM calls for #1 or #0 grease. Standard bearing/chassis grease is #2 (too thick-will sling out to the knuckle housing and not touch the axle). You will have a problem finding #1 or #0 (it is available and others have special ordered it). However, since the older axles are a CV joint, then a modern CV joint lubricant will work. It is thicker than oil but thinner than grease. I believe some use the knuckle pudding recipe to substitute for the universal lube -- the only down side is the consistency is a guess and it's messy to mix.

Some that post here have been using 140wt. for quite a while and have reported in earlier posts they have no leaks. This tells me that anything at or above the viscosity of 140wt. will not leak. This lubricant in your knuckle must also sling up and lubricate your upper king pin bearing, another trick bearing/chassis grease cannot do (although I have packed mine just like a wheel bearing as a precaution).

Since these vehicles are old and the only printed material is reprints, you cannot expect or hope "Joe Parts" behind the counter, no matter what store he works at, to have any idea what is correct. You can ask them for advice to see what they'll say, but more often than not, you'll be telling them what is correct.

Greg: When I get around to the knuckles, what are some mistakes a novice might make, or an expert who isn't paying attention, when "servicing" the knuckles and replacing the gaskets?

Steve: When replacing the felt and seals do not over tighten the metal half rings that hold the seal and felt in place . try to tighten equally otherwise the ring will squash in at the bolt and bend the ring in and it will leak in between the bolts (torque specification for steering knuckle seal retainer bolts 15-20 foot pounds) I did like Rus and packed the top kingpin bearing with grease. Steve

Daryl: Before tearing down the entire spherical assemblies, do some simple checks first.

Kingpin bearing: This is described in the SM but simply put, with one wheel jacked up off the ground grasp the top and bottom of tire and try to wiggle back and forth. If there is excessive play in the kingpin bearing assembly, then it must be disassembled to service. If you have no noticeable play, then I would try to suck out the 90 weight and replace with as close to 140 as you can obtain and see if the seals are still working.

Another often overlooked detail is that all of these model 25 front axles were designed to run with drive flanges and not lockout style hubs. In order to acheive proper lubrication of the upper bearing, the axle must turn in order to "fling" lube up to the bearing. With lockout style hubs installed, the axles are no longer turning when the transfer case is in 2 wd. This is why many have "packed" their upper bearing like a wheel bearing and also why it is necessary to drive regularly for a distance with your hubs locked in if you run locking hubs in order to keep the upper bearing from drying out.

Oldtime added: Note that kingpin bearing information is part of the Steering Checkup.

The hemisperes can become striated with deep grooves from dirt particles being left upon the hemisperes. They should be smooth without gouges or deep striated scratch lines. The hemispere wiper/seals cannot effectively seal those conditions.

Red: By tearing the assembly apart, you kill several birds with one stone:

1. You get to clean the old grease out. Don't underestimate how hardened that stuff gets.
2. You'll determine the type of axle you have.
3. You'll see if anything is broken, worn out etc. This is a perfect time to determine if the joints are still good.

About the sphere: some grease/oil is supposed to be lost to the outside, even with good seals. Clean them with solvent first to remove all the hardened grease, then maybe go over with emory cloth to smooth ridges. That hardened grease by the way, is no doubt in the knuckle as well and on the axle joints, bearings, etc.

JROD: I just redid my entire sphere. While in there I installed seals. There was nothing left of the seals in there. I found that I could not get the "old style" thick retainers on with the felt and neoprene. My friend and I even used vice grips to try to put enough pressure on the whole area to start the bolt threading. I switched over to the cheap thin ones that came with the seals, and they seemed to fit ok without warping. Did I install something incorrectly?

Rus Curtis: There's so many things that could be done by a previous owner that you wouldn't know about. For me, I always assumed if I took it off, then it's original and should work when I put it back together. I'm getting better at cross-checking things, especially the hardware. My Parts Manual lists those bolts as 5/16" - 24 x 11/16" but shows them on the diagram below with the old style seals (90K JPEG).

Early CJ-3B steering knuckle

Would they work with the new style (split style)? Perhaps a 5/8" would work, perhaps longer. I would feel very uneasy if I needed to clamp or squeeze anything to reassemble it, unless the procedure specifically calls for it. The thicker retainer shouldn't matter that much. You indicated you didn't have much to observe or study when you disassembled. The split style installation procedure (100K JPEG) indicates there is a way to install the seal backwards. Hopefully, you got the seal in with the metal backing towards the wheel. If you're not sure, it would be worth it to take the metal retainers off and verify since the knuckles don't need to be torn down.

The above image with the old style hemisphere wipers is from my Parts Manual. The later Service Manual image below shows the currently available seal that I found on my Jeep.

Early CJ-3B steering knuckle

Also I did note that the earlier image shows shims on both upper and lower kingpins whereas the later image shows the upper kingpin shims only.

Oldtime: Excellent observation. The early kingpin caps have identical part numbers while the later kingpin cap numbers are different from top to bottom.

So what exactly do you put inside?

John J: Okay, so you can't buy 140 weight oil to put in the front steering knuckles like the specs called for. Some have suggested 90 weight gear oil, but the experience says it leaks out since it is ultimately too thin.

Suggestions of bearing grease are not favored since it is too thick and the top bearing won't ever get anything thrown up to it (since the grease typcially gets pushed back and away from the joint and doesn't settle back).

Others have suggested a "pudding" of 1/2 grease and 1/2 90 weight gear oil in a best effort to replicate the 140 weight gear oil -- something like molasses.

I've seen a suggestion for using STP. What about Lucas (non synthetic) 85W-140 and grease, or even Lucas Oil Additive since this stuff is really thick? Or, how about 600-weight gear oil that is used for Model T rear ends?

Kent: Yes 85-140W will be great. Lucas Hub Oil is about the best. Have even used Snapper "00" grease. It is like a pudding that will work very well in ones that are bad about leaking and will lubricate well. If you've got lockout hubs like I do, just remember about every two weeks to lock in the hubs and go for about a mile drive to keep all lubricated.

Dougie: I'm using regular Valvoline 85W-140 from the local parts store in the knuckles. It leaked past the felts at first, but now that I've been driving it pretty regularly, I'm just getting a few drops out. Most of my minor leaks have gotten a lot better over time.

Land Rover greaseJyotin: What is 85/140 weight oil? Well at low temps it is 85 weight and at higher temps, say 100 degrees it morphs to 140 weight oil. So if one is concerned about 90 weight oil leaking out, then 85 weight oil ought to be somewhat worse -- that is, until you get those steering knuckles up to 100 degrees which could be never.

140 weight oil is tough to find, but last time I needed some I went to a oil dealer under lubricating oils in the yellow pages and found some. Most straight 140 weight is not used in automotive applications, so you'd need to think "outside the box" to find it.

Maxx had a suggestion: 140 weight. Can't find it nowhere? You local chain parts store won't have it and the people behind the counter will have no idea of what you are talking about. Chain stores stock and sell the 400 most popular parts nation wide.

Try the parts store that you have avoided. The one that has been there for 25+ years and has a couple of stools for you to sit on when buying something. The same person who takes your order rings you up at the register. The floors aren't waxed and they likely charge about 5% more than the chain stores, but they ask you name when they print up an invoice and remember you after a few visits. They will have 140wt in quarts, and order a 5-gallon size if you want it.

Properly installed knuckle seals will not leak. Pumping knuckles full of grease or any concoction related has been responsible for more hacked up Saginaw conversions that you can imagine. Pumping the cavity full of grease will cause the upper king pin bearing to fail and result in difficult, erratic steering, and wander. Hence the bad rep for the Ross box.

Bobster: Mobil SHC 634 Synthetic gear and bearing oil, 140 weight -- you can buy it at Grainger or probably order it at NAPA.

Land Rover greaseChet: Do you have a Land Rover Dealership nearby? If so, check out Land Rover "one shot swivel housing grease STC3435. Land Rover has/had our type of knuckles and this appears to be just the ticket. I considered making the "pudding" myself, but this was too easy. Buy one tube for each side, and just squeeze it in... easiest and cleanest part of the rebuild!

Greg: Warning on the price of the Land Rover grease: It's $20 for a small tube. John Deere's Cornhead grease tube is $3.50 a tube. Land Rover doesn't indicate and won't tell me what's in their grease. John Deere reveals what's in their product.

John J: I went to the parts department of the local Land Rover dealer here in SW Florida. They had it in stock. It's a current item/product. One tube for each side. It was less than $30 for both tubes.

Jeff: It just seems wrong to use Land Rover grease in a Willys! I'm sorry but I personally have to draw the line on that one, LOL. I'll stay with my current recipe. But I am glad you found a product that works.

140 weight gear oilJax: You might check out John Deere, they make a lubricant called Special-Purpose Corn Head Gun Grease -- AN102562.

SPM1US: My .02 is for the John Deere Corn Head grease. It is designed to lubricate the knuckle bearings, not the wheel bearings, and contains "Moly" (Molybdendum Disulphide) which is a superior additive for extreme pressure and anti-wear. The 14 oz tubes can be had for less than $4 last I bought them, delivered to your door or go visit your local JD dealer. The viscosity of the Corn Head grease works quite well in the closed knuckle application.

Frank: The characteristic of both the 0 and 00 "liquid grease" or "fluid grease" is what is called thixotropic. The lubricant is gelatinous until agitated, or stirred. The John Deere Corn Head fluid grease is a similar product used in corn harvesting equipment. It has the same thixotropic properties.

One of the reasons this stuff stays in the closed steering knuckles is that it liquifies where the universal joint spins in it. It is thrown upwards to the upper steering knuckle bearing and the lower bearing is immersed in it. The movement of knuckle steering back and forth forced the liquified grease through the bushing into the hub and the wheel bearings, lubricating them as well as any 70 to 140 wt gear lube could.

But where it is not agitated much around the seals it maintains more of a, here is that word again, "pudding" consistency. It wets the ball enough to provide the sliding wipe of the rubber seal keeping the ball surfacing from wearing excessively and keeping the grit wiped away. But, it doesn't run out of seams and minor wear gaps like the honey consistency of the straight gear lubes.

Castrol greaseThe Castrol SHL 00 product is about $9.00 for a 12 oz tube. The tube is dispensed with an inexpensive caulking gun, not a grease gun, through the knuckle filler hole. Easy, fool-proof, and inexpensive. Formulations contain the EP additives that are rated to not corrode copper and bronze.

Eric Lawson described his method, which also involved a caulking gun: I've tracked down an industrial lubrication supply place in Phoenix, AZ that sells lubricating greases in NGLI 00, 0, 1 and 2 "thicknesses". The person who answered the phone said most cities should have a similar business and certainly any town with active mining or gas/oil well drilling will have such a business.

00 grease was described as much thicker than pure STP..."that it would pour if you got it hot, were paid by the hour and milking the clock". 0 grease was described as "would sort of creep and level itself out, even in the winter". 1 grease was described as "like 0, but only in the summer".

The stuff comes in 35lb containers for around $75-$80. They have some quart can size samples. I'm going to get some and see how it works. I'm thinking of using 00 for the steering geearbox and just like the book says, 0 or 1 for the steering knuckes. The #1 grease does come in tubes. the 0 and 00 come in 35lb lugs because a tube would probably be empty by the time it arrived.

When my dad did some mining work, I remember seeing 0 and 00 in caulking gun (NOT grease gun) tubes, but that was a VERY LONG, LONG time ago.

I ended up going this route because I couldn't find the Land Rover swivel housing grease. There is a local Land Rover dealership, but they didn't have any and never followed up with a price when I wanted to order some. I got the #1 grease, Shell CMX 1. I paid about $30, including tax, for a box of ten grease gun tubes. I think it will work pretty well.

I've been slowly working on the Jeep -- a FC-170. I know it's not a CJ-3B, but the front axle is about the same and I figured it might be useful info for the 3Bs. Anyway, I've finally gotten around to putting the NGLI #1 grease into the steering knuckles. It took about 1-1/2 14-ounce tubes of grease per steering knuckle.

It took a while... work the grease gun... switch arms, switch arms again, rest while spinning the front wheel to move the grease around. Anyway, I finally reached the point where no more grease would go in and I waited a while. That was quite a workout....

As I turned the wheel and looked in the fill hole, I could see the grease flow slowly by hole, so I'm sure the U-joint is submerged in the grease. My guess is that when I'm driving, the grease should get splattered up into the top knuckle bearing.

Thanks to Rus Curtis, Ken (Oldtime) Bushdiecker, and all the other contributors. Thanks to Chet Couvillon, Greg Gianas, Mark Dulken, MrTexas and 54WillysJeep for photos. -- Derek Redmond

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Last updated 2 March 2017 by Derek Redmond redmond@cj3b.info
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