Controversy Over Steering Gear, Closed-Knuckle Axle and Wheel Bearing Lubricants
This exchange is from the magazine’s short-lived “forum”. Unexpected contention around this thread led to the forum’s closure. On a go-forward, enjoy using the ‘Q&A’ sections at the magazine—and expect a civil, constructive dialogue!
Frank here…I began a thread about steering knuckle grease on your forum. I saw some of your video about the overhaul, but my slow computer wouldn’t play it. So I did not see what your thoughts were on lubrication…It was an old Jeep book that educated me on this form of grease. Been quite a little side project for me, so hopefully you will be interested and look into this.
Reply below from Moses…
Hello, Frank…Thanks for the details on knuckle grease. At my recent workshop presentation for the Midwest Willys Reunion, I was surprised how much discussion there is about closed steering knuckle grease. This is apparently a large concern…
I looked at your thread links. The traditional Willys and Kaiser closed knuckle grease was NLGI Grade #0 (winter) and #1 (summer). A modern equivalent that I like is the Texaco Starplex line, which I prefer for its viscosity characteristics and affordable cost. The grease is available through Texaco outlets and bulk plants. I buy a case at a time of standard grease cartridges. Here are the “Useable” temperature ranges for various Starplex types:
Starplex 681: -40F to 325F continuous
Starplex 1: -30F to 325F continuous
Starplex 2: -20 to 325F continuous
Each of these greases will sustain short exposure to 450F with a 450F drop point. I use Starplex II (an NLGI rating #2) for wheel bearings, chassis and U-joints. Starplex 681 and Starplex I have an NLGI rating of #1, which is better for the steering knuckle cavities at my high desert living environment. (681 is better for a cold or changing climate than Starplex I.) During assembly, I pack the axle shaft joint and the knuckle cavity with Starplex I. Occasional checks and top-off involve clean Starplex I out of a grease gun.
Since the axle shaft joints do not have seals, the rotating axle shafts will scoop and replenish the U-joint grease. As I shared with the Willys crowd, you should periodically lock the freewheeling hubs to allow the axle shafts to sling grease into the upper kingpin bearings.
As for Ross TL steering (cam-and-lever) lube, the Jeep recommendation is simply SAE 80 wt. gear oil, an EP (extreme pressure) base stock. Studebaker and Willys owners get creative with this gear, substituting semi-fluid grease as the gear gets older and wants to seep out oil from the sector/lever shaft seal. (Actually, Studebaker recommends an SAE 140 wt. EP gear lube in the Ross gear and SAE 90 wt. in the Saginaw recirculating ball-and-nut gear.) The special semi-fluid substitutes are often band-aid alternatives to a rebuild.
On that note, semi-fluid greases like Marfak from Texaco are not always rated for EP (extreme pressure) use. For that reason, I’m not an advocate for Brand-X semi-fluid grease unless a clear EP rating is available. SAE 80 wt. or SAE 140 wt. are each EP rated gear oil types.
In this modern era, we have multi-viscosity 75W-140 synthetic oils plus conventional gear lube in the 80W-90 or 85W-140 types. With an EP rating, these lubes would be optimal for the Ross steering gear. When rebuilding a unit, the 85W-140 Texaco Multigear EP lube is a good, affordable choice.
So, that’s my take. If the steering gear is seeping, I generally rebuild and restore it. Resealing the closed axle knuckles is a routine service on vintage Jeep vehicles. I discuss this process in a video at the magazine website. The video is from my Willys Reunion workshop…
Trust this helps demystify the steering gear and knuckle lubrication needs. If the front axle shaft seals are leaking gear lube from the differential toward the knuckles, you will see dilution of the steering knuckle lube or seepage at the knuckle seals. If the axle support bushings are in good shape, shaft wobble will be minimal, and the axle shaft seals should hold lube in the differential cavity.
Grease conversation continues…Frank replies here…
Now the main problem with using a #2 grease is that the grease simply does not have enough oil in it, will not flow, will not discharge and protect the exposed steel from the elements.
The correct grease will move around inside the knuckle when in 4×4 mode, lubricating the upper trunnion bearing, and forms a viscous seal around the wiper seal, keeping out dirt, water and contaminants. The grease coats the ball, protecting it…
So the side I repaired, pictured here, had to be reworked and repaired again before the side that was original from 1971. Simply by not using what Ford termed the proper lube takes something that is practically maintenance free for the life time of the vehicle to a worse than average axle. Dirt gets wiped in with this situation.
Look at what’s going on inside: the grease towards the top flung off by the U-joint is still red, never used, never moved, useless. Then toward the bottom, it’s dirty grease, gritty, not so bad on this axle, but in a 12 bolt axle there was up to a 1″ build up of dirt in the bottom of the ball!
Now as I am sure you noticed about the Starplex grease, the temp stays the same on the high side and only gets better on the cold side as the grade gets thinner…More important than the rheological aspect of this is the viscous seal that forms around the felt wiper and coats the entire knuckle through the capillary action of the felt wiper oil seal.
Moses replies to Frank…
Frank, I’m receptive to others’ experience, and your photos are quite convincing. Is there a semi-fluid grease that meets EP standards? If so, will that grease stay in the knuckle cavity of a vintage Spicer axle, or does it wick into the axle housing?
On an axle with an axle shaft grease seal just inboard of the knuckle, there would be no issue. The vintage Jeep-Willys’ use of a thrust and bushing is not a barrier to oil flow, however. Would the semi-fluid grease, with EP rating, want to wick into the axle housing or out of the spindle and knuckle seal?
You have experience here. Please suggest a semi-fluid grease that meets the EP standard, one that will stay put in the knuckle. I fully agree that an oil base would be better for slinging lube to the upper knuckle, likely working into the axle shaft U-joint more readily, too. As a further concern, though, is there a semi-fluid grease that meets the EP requirements of a U-joint under torque load?
Frank responds… Thanks, Moses,
As far as it working its way through the spindle out to the wheel bearings, yes, this same lube is used in the wheel hub as well. And as far as it working its way back into the axle tube, sure, I actually like to over fill this a bit from the 1/2 static level by tipping the rig up on its side a bit. This doesn’t hurt , just adds more of the unique grease that old man Willys used to draw away moisture from the steel.
Also, this sodium-based grease, used in areas that are prone to leakage, is well known to do extremely well when subjected to shocking and pounding. EP rating? Extreme pressure, well no matter how extreme the pressure, a fluid will not compress. What any lubrication expert will tell you is that an oil is better than a grease because of its higher resistance to oxidation.
This semi fluid just has more oil in it. EP additives? This grease does have the Molybdenite additive.
Picking it up…I found the page you tried to upload, Frank. Here’s the official quote from Jeep:
“Sodium base lubricants are used at the factory for initial fill of the wheel bearings, front axle shaft universal joints, and propeller shaft universal joints. Because mixing of sodium base and lithium base lubricants results in a thinned-out mixture that can bleed through seals, always use sodium base wheel bearing and universal joint lubricants on ‘Jeep’ vehicles [closed knuckle era]. Should oil leaks occur at these bearings, thoroughly remove the old lubricant before new lubricant is added.”
This emphasizes the importance of not mixing lube bases. When you move to the lubrication chart in the same manual (official Service Manual for ‘Jeep’ Vehicles, CJ-2A through Kaiser CJ-5/6), Jeep recommends a steering knuckle lube of NLGI #1 base for summer and #0 base for winter, footnoted as a sodium type grease. Recommended wheel bearing grease is also sodium type, however, the wheel bearing grease is noted as “Wheel Bearing Lubricant” and the front axle shaft joint lubricant as “Universal Joint Lubricant”.
In seeking a grease that will work for both the wheel bearings and the axle shaft joints/knuckle cavities, keep in mind that #1 and especially #0 grease are very thin. Wheel bearings, according to Jeep, use #2 grease (sodium variety) on these vintage closed knuckle axles.
You describe using the same grease for both. What is that grease, and is it rated for both universal joints and wheel bearings? What is the NLGI rating (i.e., #0, #1 or #2)? Have you found a sodium lube that meets the requiremments for both? When you discuss semi-fluid grease with an oil base, what is the NLGI rating?
I have very descriptive grease listings from Chevron and Texaco, each has a variety of niche lubes. I still have extreme pressure (EP) rating concerns, and I’m curious how you bridge the wheel bearing and axle joint requirements with a single sodium base lube or a “semi-fluid” lube. While the closed knuckle is a cavity that can somewhat contain an oil base lube, how do you contain such lube in the wheel bearing area?
Frank’s response… Not sure why Jeep manuals spec a #2 grease in the wheel bearings when it’s clear a thin lube will work its way through the spindle. As to some Jeep books spec’ing a 140W oil for the knuckle, that without any doubt will work its way out to the wheel bearings and mix with the #2 grease. This is actually a real bad idea that can lead to bearing failure.
When I read what is mentioned by Jeep about filling the wheel bearings and related parts in the knuckle, it would all be the same grade.
EP ratings? This grease may be before the time of EP ratings, don’t know, in reading up on this sodium based grease that was used by Jeep, three things make it a easy choice for Jeep and this application:
1) used in areas that are prone to leakage
2) known for extended service intervals
3) known to do extremely well in areas that are subjected to severe shocking and pounding
Hi, Frank…I did some research in my Texaco resources and narrowed down a number of products that discuss your goals. There are two issues worth emphasizing, and we each have called attention here: 1) never mix greases and oils of a different base stock, as this can cause grease breakdown and parts failure, and 2) avoid using gear lube in the knuckle that can migrate to the wheel bearings and dilute or react with the wheel bearing grease.
I also emphasize that although Jeep and others turned to sodium based lubricants “in the day”, greases have evolved to perform well with mineral and synthetic stocks other than sodium. For your benefit and that of others, I have copied details on a variety of contemporary grease products. Some are niche products, others more generic. In any case, if one were to select and test any of these products, all previous lubricant should be carefully removed from the axle shaft joints, knuckle cavities, wheel bearings and hubs.
In reviewing different grease choices, several Texaco footnotes came up that are valid and useful. Here are a few:
1) “Marfak Heavy Duty [fibrous sodium soap grease] is primarily used as an assembly aid for needle bearings. Previously, it was widely used for wheel bearing lubrication. Today, most equipment manufacturers require a premium, high temperature extreme pressure grease like Starfak or Starplex.”
Note: Starfak is available as thin as semi-fluid 0/00 NLGI rating; Starplex 681 and Starplex I each have an NLGI #1 rating.
2) “Molytex EP has been successfully used in constant velocity joints (CV-joint) in front wheel drive automobiles, universal joints (U-joints) and for chassis lubrication. The presence of moly provides added shock loading protection.”
3) “Multifak EP greases are non-corrosive to non-ferrous bearing metals as well as steel.” [This could apply to items like the bronze bushings that support the closed-knuckle axle shafts.]
4) “The EP additive package found in these Starfak synthetic greases provides extra protection to metal surfaces in shock loading situations. During a heavy shock load, the lubricant film between metal surfaces can be ruptured. If lubricant film rupture occurs, the superior EP additive package in these synthetic greases can provide the extra level of protection that is needed.” [This reflects my reasoning around the use of an EP-rated grease.]
You will find many other insights in the actual grease descriptions and properties. Note each grease type’s speed rating and temperature range for roller bearings. When considering temperature characteristics, keep in mind that the wheel bearings and knuckles do get exposure to brake heat. Chemical engineers create niche products for a variety of uses. Study these details carefully, and clear options will be apparent.
Although the closed knuckle axles are “older” technology, there are many restorers and enthusiasts who still enjoy working with these systems and doing a quality, safe job. Grease and lubricant choices must take the needs of axle joints and wheel bearings into account.
Scans of some Texaco offerings are available at this PDF link:
Note: I offer these listings for your review. It is not my intention to endorse or recommend a particular grease but rather to expand the discussion to include the many variables involved in making grease choices. For a complete guide to the Texaco lubricants, contact your local Texaco Bulk Plant or wholesale distributor.
Closed-knuckle enthusiasts need to follow safe, practical grease choices based upon currently available products and engineering.
I ask that readers keep me posted on findings and experiences.
Back to Frank…
Now those newer Texaco greases such as starfak, multifak are great greases, but the sodium based marfak is discontinued, no longer available or so I have learned.
As far as these greases working for both the wheel bearings and wheel joint in the semi fluid or very thin #1 would do just fine, except maybe in one area, leakage or discharge from the wiper seal.
Sodium based grease used in areas that are prone to leakage are known for the ability to cling to the knuckle, so it is for this important reason that I felt it would be nice to track some of this sodium grease down and re-introduce it to the Jeep and other markets…There is old man Willys’ caveat of mixing them [sodium and lithium greases], causing oil leaks…While there are newer greases, I still don’t think they hold a candle to Old Man Willys goop, being that it’s found in rigs that last a long time.
Hi, Frank…Since you have sent many looking for ‘Old Man Willys grease’, where is a source for automotive sodium base grease? You share that Marfak is not available, apparently the result of the Texaco-Chevron-Shell convergence. (Marfak was listed in Texaco catalogs within the last five years. You note that it’s no longer available.) Sodium grease is available in India, perhaps exported to North America from there. I’m not clear that an NLGI 0 or 1 rating is available in the India greases, as the grease I’ve seen is described as “wheel bearing” type or WB, which is generally NLGI 2.
So, outside of India, where can folks get a sodium base #0 or #1 NLGI grease as you and Willys recommend for the knuckles? Also, where can they get a #2 wheel bearing grade NLGI in sodium type if they want to use #2 in the wheel bearings? Willys does recommend sodium “wheel bearing” grade grease in the wheel bearings.
We recognize that Willys recommends #0 (winter) or #1 (summer) NLGI grease in the steering knuckles. I will not use NLGI 0 or NLGI 1 in the wheel bearings, however, especially in a hot climate and near the brake mechanisms. In any case, it is essential to use the same base stock in the wheel bearings as the closed steering knuckles. Whatever the NLGI rating, the grease type (sodium, calcium, lithium, moly or polyurea) should be identical and fully compatible between the knuckles and wheel bearings.
Given that lithium or polyurea are the two thickener ingredients in the more popular and available greases, the question is why sodium has been dropped. Fibrous sodium was a popular pre- and postwar grease. Marfak has a patent dating to April 1924. These fibrous greases adhere well, resist dust, take a shock load and have good temperature range. Texaco suggests however, that sodium grease (in referencing Marfak) has been supplanted by “premium, high temperature extreme pressure greases like Starfak and Starplex.” Starfak has a synthetic oil base stock and is recommended for trailer hub bearings and gear boxes. I shared data on Starfak in the PDF, and it is available in NLGI 1, 2 and 0/00 ratings.
Given that these modern greases have quality adhesion, extreme pressure ratings and anti-rust or oxidation additives, perhaps you can explain why none of them meet your standards. Lithium or polyurea is found in expensive greases, so saving cost is not a factor. (Sodium would actually be less expensive to produce than either lithium or polyurea.) In this modern era, sodium has, as you quickly noted when I listed Marfak, virtually disappeared from automotive, industrial and heavy duty applications.
Unless there is a fibrous sodium grease available in NLGI 0, 1, and 2, there are contemporary automotive greases that work well with CV axle shaft joints in modern front wheel drive vehicles (and 4x4s with half-shafts and CV joints). These greases must fold back into the joint and cannot sling out and leave the joint dry. If such grease is available in NLGI 0, 1 and 2 (or semifluid SF if and when specified for a given application), there would be a choice for winter, summer or wheel bearing applications…You call attention to the chassis greases that flew off your axle shaft joint in the Ford example. The CV-joint greases must flow back into the joint in service and adhere to bearing balls under extreme pressure loads. They also work inside a cavity of sorts: the CV boot.
As for the coating or film on the exposed housing ball, that must be a dust resistant grease. Would a polyurea grease with a viscous, synthetic oil base stock provide that kind of protection? Have you experimented with advanced formula polyurea greases in 0, 1 and 2 NGLI ratings? A grease like Chevron Black Pearl EP, rated in NLGI 0, 1 and 2 types? (1 and 2 are wheel bearing rated, 0 or 1 could be used for the axle shaft joint and knuckle.) Any experience with these greases?
What do you think of polyurea with synthetic oil base, a high-end automotive application grease with the specified NLGI rating?
To be continued…
P.S.: There was nothing “special” about the grease your ‘Old Man Willys’ and Kaiser used in 1941-71 Jeep 4WD front axles. Sodium was a common choice, and a wise one I agree, for a vehicle subjected to everything from the Burma Road to the Battle of the Bulge in winter. As I note, Marfak was around since 1924, and Willys had no trouble, I’m sure, finding sodium NLGI #0 and #1 for the closed steering knuckles and #2 for the wheel bearings. There was likely nothing “proprietary” about sodium NLGI 0, 1 or 2 in the Willys first fill, and I’ve personally never seen a “Willys” can of grease. Engineers worked with what was commonly available at the time, and both sodium and lithium were available. Sodium, as you note, was the better choice than lithium at that level of grease development. While these vintage greases were well suited for this automotive application, they hardly compare to specs of today…
Back to Frank…
So as far as why sodium grease was dropped, I have a couple ideas. It is used at production level for instance in these newer Toyota rigs, but not after market. As to why it was dropped, not available in the aftermarket?
Well, I have come to a couple of conclusions but would like to hear yours, as far as this extensive study in 2008 it was still the best way to make grease:
Production of grease from used lubricant: a feasibility study by Nabil Fikri , Yaakub (2008) Production of grease from used lubricant: a feasibility study. EngD thesis, Universiti Malaysia Pahang.
“Grease is a mixture of a fluid lubricant usually petroleum oil and a thickener v (soap) dispersed in the oil. The base oil (petroleum) can be changed by using the used lubricant. Other then base oil, thickener may play an important role in the mixture. Soap thickeners are formed by reacting metallic hydroxide, or alkali, with a fat, fatty acid, or ester. Since the petroleum prices increase each year, using used lubricant as base oil is the best solution to produce grease in the low cost at the same time it will decrease the water pollution. Three types of soap are used in this production that is aluminum soap, calcium soap and sodium soap. Viscometer was used in this experiment to analyze the quality and performances of grease product to select the best type of soap to produce grease. The viscosities of grease are tested by changing the spindle speed for each type of soap. The different percent of soap are used to know the effect of percent of soap to the viscosity of grease. In this experiment, grease was successfully produced from used lubricant. The viscometer test and sample preparation on grease was visualized in this research, where the viscosity of grease was decreased with the increasing of spindle speed and the viscosity was increased with the increasing of percentage soap (thickener) added. The best way to produce grease is with sodium soap, where sodium soap is the strongest thickener compared to another thickener. Using this type of soap, only small amount of this thickener needed compare to another type of soap.”
Moses, sodium works the best, cheaper and easier to make…What are your thoughts as to why a grease that works this good is kept under wraps? Engen Grease is just an example of lithium/calcium greases that would be ideal and work, basically it is this: the lube needs to flow like a oil but be thick enough not to leak out, and used in both wheel hub and axle joint housing. I think John Deere corn head grease in the #0 grade is polyurea and would be great.
Regardless, the grease that I have for this application thru Novak Adapters is proprietary, a reformulation of this semi fluid grease from yester year.
Moses replies to Frank…
Frank, sodium grease must be cheaper to produce. However, the older sodium greases require regular replenishment and interval service. It is reasonable to assume that lithium, molybdenum and polyurea thickening agents hold up longer than sodium. I believe that the use of sodium grease declined with long-term interval service and “permanently sealed” U-joints and steering components. (Unfortunately, this trend also led to poorer vehicle maintenance.) Vehicle manufacturers were competing for long-term intervals between routine service work.
While we have waxed nostalgic about “Old Man Willys Grease”, let’s not forget that vehicles in
the ’40s and ’50s were subject to lubrication each 1,000 miles for chassis areas and U-joints,
each 6,000 miles for wheel bearing service, and breaker point ignition tune-ups were at 6,000-
12,000 mile intervals! Imagine modern consumers following such intervals. The full-service gas stations have disappeared, and “self-service” means putting gas in the vehicle and maybe checking the oil. Today, most vehicles get neglected to the point of parts failure.
I worked at a Standard Oil/Chevron station during high school years in the mid-‘sixties. I worked professionally as a light and medium duty truck fleet mechanic by the late ‘sixties. Following rigid preventive maintenance schedules, I used detailed grease charts and lubed vehicles constantly! On that note, molybdenum or “moly” grease became popular during that period.
Sodium is cheap to produce, likely the reason for its popularity in India. Molybdenum or lithium greases cannot be as cheap, and in the future they will be even more expensive with lithium batteries everywhere, including hybrid automobiles. Polyurea holds promise and is not a non-renewable mineral like lithium or molybdenum.
Polyurea is recommended for CV-joint use and enfolds into the CV-joint rather than flinging off as you illustrate with some greases. Polyurea grease tolerates substantial heat, lubes bearings well, meets EP standards and is a “permanent lube” in many sealed bearing applications. Blended with the right oil stock, polyurea may well be the solution.
We agree upon the importance of proper NLGI rating for the knuckle lube. I am aware of the #0 and #1 recommendations from Willys/Jeep. Willys and I agree that wheel bearings require wheel bearing rated grease (#2).
My resistance to #0 or #1 in the wheel bearings is not the ability for these greases to lubricate. It has more to due with the temperatures generated by the brakes and how that affects the wheel bearing lube. If this were a non-issue, there would be no call for upgrading greases to “high-temp” types for disc brake axles and hubs. Note that all of the vehicle manufacturers changed specs for grease when they began offering disc front brakes.
That said, I want a wheel bearing lube with temperature tolerance in the front hub wheel
bearings. I have less concern with the dilution that naturally takes place in the typical closed knuckle axle as grease finds its way from the steering knuckle past the spindle bushing to the hub. A free-wheeling hub mechanism might deflect some of this migration, helping to isolate the wheel bearings from knuckle lube. (There’s still a gap between the outer spindle end and the free wheeling hub mechanism, a path for grease migration.) An early Willys axle without freewheeling hubs installed has more likelihood of a thinner knuckle grease migrating out the spindle and diluting the wheel bearing grease over time. Use of oil in the knuckle would increase this risk.
Given the needs of the inner knuckle seal, lubrication of the upper and lower kingpin/trunnion bearings, the wheel bearing lube, and a hollow spindle with an axle shaft spinning within, my concerns are: 1) adequate, proper lubrication at each area, 2) lack of seepage from the inner knuckle seal, and 3) minimal, if any, migration or mixing of specified lubricants.
You have highlighted the effectiveness of fibrous sodium grease and semi-fluid lubricants. I think this works well in the knuckle at #0 or #1 NLGI rating. (#1 for hot climates; #0 for cold climates; changing these seasonable would be a pain, realistically.) As you note, knuckle lube needs to flow back into the axle shaft joint and not fling outward and stick to the housing (thus starving the axle shaft joint for grease)…So, strictly for the steering knuckle, my contemporary lube choices reflect your findings. As an alternative to fibrous sodium grease, however, I’d likely use a polyurea CV-joint grease with an NLGI rating for this application. Interestly, 1.5 is apparently a norm for CV-joint polyurea lube. (See below.)
If I were using the polyurea CV-joint grease in the knuckle, I would definitely use a polyurea
automotive wheel bearing-rated grease in the wheel bearings. In the event of mixing or dilution of these two segments, the greases would be compatible and not chemically reactive. Here is a possible scenario for use of polyurea greases:
1) Steering knuckles—Chevron Rykon Premium Grease #1364 or #1426, each an NLGI #1.5 designed for automotive CV-joints. The #1426 will also work for “other applications requiring a high
temperature, extreme pressure grease”. It might be acceptable to use #1426 in both the
knuckles and the wheel bearings.
2) Wheel bearings—Chevron Rykon Premium Grease EP for “heavy duty truck wheel bearings, universal joints, water pumps and idler pulleys”. This has an NLGI #2 rating, optimal for the wheel bearings and still chemically compatible with the steering knuckle’s #1364 or #1426.
Note: In the lithium complex grease types, Texaco’s Starfak offers compatible #1 and #2 greases as well. (#1 would work in the steering knuckle at a moderate to warm climate; Starfak #2 would be an optimal wheel bearing grease.) Starfak also offers a #0/00 NLGI grease that could work in the knuckles at colder climates. Starfak is state-of-the-art synthetic grease. I included Starfak in the PDF listings.
As for your ball coating film, you suggest that this is one of the great virtues of sodium grease and a real asset. Proof of the benefit from the film on the ball would be increased inner seal life and less scuffing or abrasion of the ball surface. Has this been tested and proven? Do you have any evidence about greater inner seal stamina by using a grease that leaves this film across the ball face? Or does the grease attract abrasive material (dirt, sand and other debris) and cause premature failure of the seal due to the mixing of grease and abrasive material?
These are my takes. I have looked at other niche greases, there are many, some have phenomenal strengths. However, I cleave toward automotive applications with a tested target, greases like the CV-joint lube or a grease designed for higher speed automotive friction roller bearings. An NLGI polyurea grease with a CV-joint rating might work well in the knuckle. All of these automotive greases I discuss have anti-rust and anti-oxidation protection with reasonable water resistant properties.
Frank picks it up again…
As for grease film adhering to the exposed bare steel, protecting it from rusting and pitting: Yes, that could be easily tested and proven, exposed bare steel tends to rust, while steel covered with nice film of grease won’t. In Old Man Willys books he states to cover the ball with extra grease in the event of prolonged storage.
As for seal life, dirt that would otherwise be kept out with a properly lubed knuckle, works its way into the housing and collects near the axle seal. Then this dirt acts as a grinding compound and chews into the steel axle causing a groove in the axle.
“Or does the grease attract abrasive material (dirt, sand and other debris) and cause premature failure of the seal…?”
Actually, Moses, this is a good thing the dirt, dust, and grease collect on the wiper seal forming a additional barrier for keeping contaminates out of the axle. For anyone that has repaired/serviced one of these axles and had to chisel off this grease and dirt compound, it can be quite formidable, forming a very effective barrier of additional protection.
Actually one of the things mentioned about this (by Marfak) sodium grease, is that it forms an additional sealing barrier. On one 1966 Dodge axle with the correct form and grade of grease (original with what Dodge called “short fiber grease”), inspection revealed what appeared to be #1 grade. Keep in mind this grease was over 40 years old and may have changed or “oxidized” over the years.
Inside the knuckle, all parts were in excellent shape, only required soft parts, seals and gaskets. The U-joint, lower trunnion bearing and upper bushing were reusable.
Dodge short fiber grease is a decent bread crumb clue, it is associated with soda soap greases which is another name for sodium base, although information today says short fiber grease is silicon base. Regardless, a grease of a more liquid nature. There is a good article called “Uses for Short Fiber Grease”.
So as far as this grease not lasting as long as lithium, this does not seem to be the case or need to be replenished or maintained. Of course this is the thinner grades, #1 or thinner, of any base with more oil in them, resist oxidation better, or in layman’s terms, just don’t “dry up”.
Frank, let’s sum up conclusions…
Your position is that sodium grease meets or exceeds the needs of the closed knuckle front axle. You assert that fibrous sodium grease meets these requirements:
1) Provides the fluidity and temperature requirements for lubing the axle shaft joint; being fibrous and fluid, the grease will not fling off the joint and starve the joint or knuckle trunnion (kingpin) bearings. This grease is well suited for the axle shaft joint and trunnion/kingpin bearings.
2) It is your position that sodium grease, even down to the thinnest #0 NLGI rating, provides the needed lubricating ability and temperature resistance to serve in the wheel bearings of a drum or disc brake system.
3) Sodium grease (as thin as NLGI #0) will weep from the wiper seal at the inner side of the knuckle, just enough to leave a protective and useful film over the ball ends of the axle housing. Periodic lubrication replenishes any grease that leaves the knuckle in this manner.
4) You assert that fibrous sodium grease in thinner NLGI #0 consistency will work at both the knuckles and wheel bearings, eliminating the need to use specified #2 grease in the wheel bearings.
My view, after our exchange, rests here:
1) Fibrous sodium grease does satisfy the requirements for a closed knuckle live front axle. Willys recommends #0 (winter) or #1 (summer) NLGI grade sodium grease for the steering knuckle cavity and axle shaft joint.
2) Willys recommends a fibrous sodium grease designated “wheel bearing” type for the hub wheel bearings on closed knuckle axles. “Wheel bearing” grade fibrous sodium grease is a #2 NLGI rating.*
3) I prefer using specified grease, and if using a fibrous sodium type grease, my choice would be climate specified #0 or #1 for the knuckle cavities and #2 for the wheel bearings*, each of similar properties and chemically compatible in the event of migration, mixing and dilution.
*Note: I use a disc brake rated “high temperature” grease for disc brake vehicle applications. I believe that the thickness of a disc rotor and its integral attachment to the wheel hub is a completely different dynamic than a drum/shoe brake setup. Regardless of whether “physics” call for equal amounts of frictionally generated heat to stop a vehicle’s mass, drum brake heat is applied to the outer rim of the drum; there is a relatively thin drum face thickness to transfer heat into the wheel hub. By contrast, a disc brake rotor is much thicker, from the caliper right to the hub area. The rotor serves as a bigger heat sink, which dissipates more heat into the hub and wheel bearings.
For proof, try this on a drum then a disc brake vehicle of similar weight: Work the brakes (safely!)on a lengthy downgrade; at the bottom of the grade, measure the front wheel hub heat with an infrared gun. See which vehicle’s hubs are hotter.
I recall disc brakes becoming popular in automotive applications and the issues around wheel bearing heat and bearing survival. There was just cause for the use of ‘high temperature’ upgrade grease for disc brake wheel bearing use.
4) Contemporary greases can meet the needs of a CV-joint or axle shaft U-joint. There are compatible greases for wheel bearing use. Unless a grease is clearly described as suitable for both applications, I would follow Willys’ NLGI specified ratings for the wheel bearings (always a #2) or the steering knuckles (#0 or #1, to be determined by climate). I would upgrade to a disc brake rated grease for the wheel bearings on a vehicle equipped with disc brakes.
5) As for the issue of a grease film over the ball and any advantage in terms of seal or ball life: If Willys wanted a grease film over the closed knuckle ball, then any alternative to sodium grease needs to also provide such protection.*
*Note: To prove whether Willys intended to provide a protective film at the axle ball, use the correct fibrous sodium grease at the steering knuckle and new seals. (Ball must be in top condition, smooth and without scratches.) If such a film forms under these conditions, assume that Willys intended this outcome.
6) At the steering knuckle, I would try polyurea grease in its modern automotive “CV-joint” designation (Chevron’s Rykon #1364 or #1426, each an NLGI rating of 1.5.) For this test, I might consider Rykon #1426 for the wheel bearings or use Rykon polyurea EP type grease (NLGI #2) at the wheel bearings.* Any change of grease type requires thoroughly clean parts, free of any previous grease, debris or cleaning solvents.
*Rykon #1426 meets G.M. #7843867 parts requirement; if interested in using this grease, research to confirm whether G.M. approves this product for both CV-joints and wheel bearings. For wheel bearing use, verify whether this grease meets disc brake requirements if the vehicle is so equipped.
7) The steering knuckle and axle joint lube must be fluid enough to enfold back into the joint and flow in general. It is unacceptable for grease to sling outward and cling to the housing wall without migrating back to the axle shaft joint (your point as well). Grease must also reach and replenish the knuckle kingpin/trunnion bearings.
Note that in any grease approach, to minimize grease loss or mixing of greases, the axle shaft bushings must be intact and at proper clearance; to avoid weeping excessive grease from the inner knuckle seal, the ball surface and seal must provide a smooth, quality seal.
When assembling and greasing kingpin/trunnion bearings or axle shaft joints, always pack each part thoroughly for initial protection. The same rule applies to wheel bearings, using a suitable packing technique. When filling the knuckle cavity, the type of grease determines fill level. Some greases will pump out or stress seals if packed too tightly. Churning and cavitation are an issue with certain types of grease. Always follow the grease manufacturer’s guidelines and recommendations…
Frank, we have presented the facts, the details, our experiences and opinions in a thorough, no holds barred way. My magazine’s articles and Q&A reflect a willingness to objectively discuss technical details, experience and insights.
There are many readers with 1971-back closed knuckle front axles to service and restore. May the information we have presented prompt readers to think seriously about grease types and their proper application.
You spurred discussion on an important topic. May vintage Jeep owners benefit from that dialogue.