Why Grease should not be used in a Steering Gearbox
 

Over the years, the topic of using grease inside a Model-A gear box has come up here. When I was a kid, its use was always a forbidden sin when someone asked about it at the club meetings. I think things have changed during those past 50 years of club meetings, but some are still adamant that it is a no-no to use grease in the gearbox. Maybe we can discuss it here again??

So in a typical mindset regarding Model-A gearboxes, there are low speed gearboxes and high speed gearboxes. For reference, the rear axle and the transmission on a Model-A are high-speed gearboxes. The steering gearbox would typically be considered a low-speed gearbox. In between are items such as the electric windshield wipers, window regulators, and maybe another item or two are low-speed gearboxes by definition.

From what I know about it, a high-speed gearbox typically uses a lube instead of grease so-as to cool the components such as bearings, bushings, and to remove the heat from friction created by two gear teeth rubbing against each other. In a slow-speed gearbox such as a steering gear box, a windshield wiper, or a window regulator, the friction on the bearings or the teeth (worm & sector) are not as prevalent where cooling from a lubricant is necessary.

So why did Henry's engineers choose to specify/install 600 W lube in lieu of grease? My theory is because at that time there was not an "extreme-pressure" grease invented, and so the 600W lube allowed the Sector teeth and the Worm gear to be 're-lubed' or replenished after the lube had been sheared off of the teeth during a turn while driving. Today, there are several available extreme-pressure greases that likely would have exceeded the needs for those Engineer's application. (For those who live to watch things discussed on YouTube, there is a channel called Project Farm that has produced several videos regarding the topic of greases.)

So here comes the question. Recently there was a discussion regarding Penrite grease along with a suggested alternative 00 Grease available at John Deere tractor dealerships and also at a local tractor supply store. I had looked at this product maybe a year ago and what I was told is not all "Corn Head" greases are high-pressure greases. It was explained that I should ask each manufacturer about recommended applications, ...and the brand I chose to go with is Champion's 00 lube which supposedly has the additives and the make-up that we would need in a Model-A gear box application. While we have begun to use this, unfortunately we have not been using it long enough in a Model-A gearbox to know whether it will be better than 600w over a longer term (20k-30k+ miles). Time will tell I suppose.

There is one area that I have concerns with in using this is (-unless you have a L28-29 7T sector housing.) the only way for the sector bushings to receive grease for lubrication is during the assembly process. If you study the gearbox housing, you will find it has provisions for lube to enter the sector housing, and the sector bushings are designed where galleys are present to transfer the lube to keep the sector shaft lubricated. So the question is, when using extreme-pressure lubricants in this area does the lubrication stay on the bushings to provide continual lubrication? I say it doesn't. Especially if someone has converted to roller bearings in lieu of sector bushings (-which is a whole different controversial topic!).

One other thing to note; when I rebuild a 7-tooth gearbox I typically re-machine the end of the steering shaft both internally and externally. I like to only remove enough material to remove any damage and then polish it with a worn crankshaft polishing belt. I then make a new lower bushing using oil impregnated bronze material (Oilite) and pack it full of the extreme-pressure grease during assembly. I figure if the grease gets pushed out, the oil in the bearing material will take over the lubrication process.


I welcome your comments or opinions on this, but my take on this is the Penrite and the Champion greases are likely suitable for using in the gearbox however they really do not provide enough lubrication for the sector shaft in its housing. Therefore an alternate method of lubrication needs to be used in you are using grease in the gearbox.

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Re: Why Grease should not be used in a Steering Gearbox
 

Grease: Does not pour or flow at ambient temperatures.
Oil: Flows in all ambient temperatures.

I think this is the bulk of what Brent is saying, with the added proviso of shear strength. And shear strength really doesn't matter much if there is no replenishment.

Having heard about Penrite, and not wanting to disassemble the steering box YET AGAIN for oil leaks, I ordered a pint of Penrite.

It does not behave like a grease. It flows. It is somewhere between thick catsup and thick molasses. It's quite slippery. I don't know how well it will flow into the oil channel in the sector bushing, but it likely will over weeks as opposed to minutes. This is all that's needed really. And even quicker into the needle bearing that has more and wider spaces. If you assemble with grease first, I think that could obstruct any oil from entering the bushing grooves. And grease can dry and harden over time, another reason not to use grease in places where you can't force the old grease out under pressure with fresh grease.

I installed it. I needed to rig a threaded funnel into the steering box and let it flow in over several days* before it was full - in the fall in ambient temps of 50 degrees or so.

I agree this would be entirely unsuitable for a high speed gearbox.

* Because my funnel was small (about an ounce) and I would check on it just a few times a day. Bigger funnels would allow much faster fill if you're in a hurry, but don't be in much of a hurry.

Re: Why Grease should not be used in a Steering Gearbox
 

Brent, I am not disputing what you write I just have a question. Did Ford really use 600 wt. oil and what you refer to using in your steering box or was it more like what the vendors today call 600W which I have been led to believe is closer to SAE 140-250 wt. oil according to this chart?

Also what “scale” was used for the 600wt. oil?

Gets kinda confusing.

https://live.staticflickr.com/65535/...b62bafdd2d.jpg

Re: Why Grease should not be used in a Steering Gearbox
 

55 years ago when I first stared driving Model A's, the purpose of putting grease in the steering box was so that it did not leak out and get all over the light switch parts and the garage floor. Today you can buy items to modify the steering box to keep oil from leaking out. I think a good grade of modern transmission oil that is suitable for high pressure and not harmful to yellow metal would be the proper choice. Add to that the parts needed to keep the oil from leaking out.

Re: Why Grease should not be used in a Steering Gearbox
 

I managed to dig up the specs for both the Champion grease and the Super S grease (the spindle grease available at Tractor Supply), attached below. You can see the Champion grease has a higher base viscosity and performs better on the 4-ball test, so it probably does perform better under high pressure than the spindle grease.

Naturally the Champion grease isn't available around here, gotta special-order it. That was the main attraction of the Super S grease for me.

Re: Why Grease should not be used in a Steering Gearbox
 

600W is a designation not the weight. The chart shows this as about 150 weight.

I've used both 140 and 250 weights and don't notice much difference.

Re: Why Grease should not be used in a Steering Gearbox
 

It is confusing mainly because what has been passed down from generation to generation. Kinda like what Ford called the Dash is what some call the Firewall today. I went back and changed the WT to W however this is only a difference in abbreviations. The W & the WT are basically the same abbreviation.

To answer your question more specifically, part of your answer can be found in the Service Bulletins. I don't have them in front of me now so I do not have an exact quote to look at, but somewhere it makes reference of the lube to be of 600w thickness or consistency. I have only seen the M-Spec (material specifications) number mentioned for the 600W now have I ever seen Ford's usage specification for it.

This topic has been discussed many times here in years past where the Service Bulletins specifically specify using a Steering Gearbox lube in one place, -and yet in another area it lists the Transmission and the Rear Differential as both using the same lube however does not mention the steering gearbox as using that same lube. Is this an oversight? Likely as I have mentioned over & over, the Service Bulletins were not without errors and maybe this is another one such example. Therefore I am pretty certain the context in the Service Bulletins which specifies that 600W was the viscosity of the lube to be used. I think where the confusion comes in is where the industry viscosity ratings have been changed over time. Are you just as confused now as what you were when you asked the question?? :D

Re: Why Grease should not be used in a Steering Gearbox
 

You may be correct but I am pretty sure the S/B makes reference at least once to the 600W as being the viscosity. The sentence was something like "the gearbox must use a lube equal to 600W.". It has been argued over and over and I don't know the answer, but I think the compelling argument has always been if 600W was a trade-name and not a viscosity, why wouldn't the Ford engineers have specified the necessary viscosity since '600W' was not Ford's own tradename?

Re: Why Grease should not be used in a Steering Gearbox
 

Interesting thread, and yes sometimes these lube specifications are too technical for me:)

I got tired of a puddle of 600W on the floor the next morning after filling the steering box, so then I morphed over to JD Corn Head Grease, and now THAT sounds like it may not have been the solution.

I'll just lay back and let the herd mentality 'flow' this question. I'll see who is doing what and how quickly it destroys their steering box and go from there!

Re: Why Grease should not be used in a Steering Gearbox
 

Just about! One reason is because is the 600w an ISO rating? SAE doesn't not go that high. So 600w is ~SAE 150? :p:p

Without the inclution of "ISO" or "SAE" the numbers are not telling me much. Kind of like using a metric scale to measure inches.

Re: Why Grease should not be used in a Steering Gearbox
 

Thanks for the response. This certainly is confusing and has been batted about for decades. Maybe I'm wrong, certainly won't be the first time. But, I thought the general consensus was 600W was a designation.

I've tried them all in the transmissions. I used what was said to be 600 weight and found it too heavy, 90 weight I felt was a bit light but doable.

As a kid we always used a barrel of 140 weight for everything until things changed to 90 weight. [ then we needed 2 barrels hanging around]

Its also my understanding that the grease fitting on the steering box was for the use of heavy oil [600W] pumped thru a grease gun. We always kept a gun full of 140 to top things off. Its easy to see why fellas would pump that box full of grease though.

Re: Why Grease should not be used in a Steering Gearbox
 

Here's the relevant bit from the service bulletins.
Attachment 455559

Re: Why Grease should not be used in a Steering Gearbox
 

The 600W designation was a carry-over from steam cylinder oil, which would have been widely available at the time. You can still buy it now, in fact (for steam cylinders, not gearboxes). My understanding is that the controversy comes from not being certain what property was being equated when engineers were formulating "600W" transmission/differential oil.

Re: Why Grease should not be used in a Steering Gearbox
 

I am real familiar with steam cylinder oil from owning and operating steam tractors and engines over the years. Regular 90 or 140 wt oil will not lubricate steam engines as steam will wash it away. I'm not very technical on oils but I know that a steam cleaner won't start to clean 600w off of a steam engine. The only way I have had success cleaning it off is to wash with kerosene and scrub real hard then use a steam cleaner. That's how hard it is to brake down. Worm gears also call for 600w lube.

Re: Why Grease should not be used in a Steering Gearbox
 

What about CV joint grease used in the axle joints of front wheel drive modern cars? It both flows and is extremely "clingy". To me, it is a lot like the John Deere "cornhead grease" and a lot easier to find. By the way, John Deere makes a grease for low speed gearboxes and another for high speed gear boxes. We want the low speed variety for steering boxes.

Re: Why Grease should not be used in a Steering Gearbox
 

Not sure which CV joint grease you have in mind, but that stuff is usually NLGI grade 1 or 2, a lot stiffer than the 00 stuff.

Re: Why Grease should not be used in a Steering Gearbox
 

CV grease contains Molybdenum Disulphide. That is what gives it its extreme pressure rating. The same stuff is in any "EP' gear oil which is known to dissolve some bronze bushes so take care here. I prefer graphite grease.
All that said, I use Penrite steering box lube and I'm not afraid to mix in a bit of grease or self levelling grease but remember, the steering box over here is very close to the exhaust and gets warm after a few miles. I think the lubricants you guys are using will lose viscosity and leak out quite quickly. It is a whole different consideration here.

Re: Why Grease should not be used in a Steering Gearbox
 

Synchro, the problem as I see it for you guys in Australia, is you are upside down in the world so the grease runs out of the top of the gearbox:D:D

By the way how do you keep from falling out of your cars??

Re: Why Grease should not be used in a Steering Gearbox
 

Dunno, but I don't have any trouble sitting in there and falling out!

Re: Why Grease should not be used in a Steering Gearbox
 

Maybe they wear anti-gravity boots that work the opposite way "down under":)