I am working on a Ford tractor and finding the same thing as on Model T's. Wheel bearings only need grease, not the full hub full or the cap. If you fill the hubcap all you have is a cup of grease to put on your lips like chap stick. If you fill the hub between the inner and outer bearings that is just a mess to clean out, it won't fly around with centrifugal force unless hot and then there is something really wrong if the hub is that hot.
The rear caps on a Model T should never be full of grease or have ANY. No reason for grease there as you want a dry fit and tight on the axle.
Please don't pack these areas, send me tubes of grease instead or 10 gallons of fluid for my parts washer that is now just a mess.
I have seen that maybe once on a car! Why would anyone pack the rear hub cap with grease? !
I do, for the simple reason of having spare grease if needed for the fan or anything else on long tours, more room under the seat for other stuff.
Better greasy old stuff than rusty or worn out
It was thought to be a good idea. At least it was a selling point. I have seen several versions of this:
I agree that any more than what fills the bearing is a waste.
I can see Frank's point as to having a bit of usable lube for another purpose in a handy spot but agree that it doesn't do a thing for the bearing.
And then there's this approach:
I think Frank has a good idea. It certainly would be easier than hauling a tube or gun of spare grease.
When I'm cleaning parts like this I always scrape the grease and crud out of the parts as much as possible. Cuts down on the junk being put into my solvent tank. But since my solvent tank is just a bucket with old gas in it, I guess I'm not out a lot if I have to get rid of it.
I think the hub cap that Steve shows came in a set of 4 two for the front with grease fittings and two for the rear without.
I had a boat trailer with "Bearing Buddy" dust caps that had a spring loaded end with a grease fitting on them. The inner hub bearing had a seal. The idea was that before launching, you pump grease in the hub so the spring load is putting it under a little pressure. This keeps water from getting into the wheel bearings. At least that was the idea!
Jared, where can I find the Greece gun head that fits the fittings in your picture? My 23 touring has these fittings for all the Greece points. I'd like to keep them if the gun would fit.
David, I think the Bearing Buddy set up compensates for rapid temperature changes in the boat trailer beatings. You arrive at the boat ramp after driving with warm to hot bearings and back the wheels into cooler water which contracts all the metal and seals which can then suck water into the bearings. The spring compensates for the shrinkage and keeps the bearings packed with grease not allowing water to enter.
Excess grease will actually cause overheating in hubs. This is especially true with modern vehicles running at higher speeds and loads. The correct procedure is to pack grease into all bearings and lightly coat the internal of the hub with it but just enough to prevent it going rusty.
Bearing manufacturers go to great length to educate mechanics etc of the correct procedure. Having grease in the hub cap is a good idea but I don't personally do it.
This is how I was trained.
Alan from Western Australia (currently in Canada)
Yep, now that you mention it, that was how it was explained to me so many decades ago. That was the trailer under our steamboat Mikahala, boy do I miss that boat (enough time has gone by that I miss it, having forgotten whatever problems it dealt me!).
Michael, the picture is courtesy of Steve Jelf, but I'll take a crack at answering your question anyway. I'm sure Steve will have a better answer, but here it goes.
The fitting question is known as an alemite fitting. They were the precursor to the modern zerk fittings we see today. I don't know if anyone sells modern adapters, but alemite grease guns can usually be found at swap meets or auctions for reasonable prices. We have a few on hand, since our fleet ranges from a 1914 Case car and 1919 tractors to brand new John Deere four wheel drive tractors, with a little bit of everything in between. Gotta make sure you can keep everything lubed up if you want to make it last 100+ years.
If you aspire to have a fully-equipped modern shop, you must have this.
Flat-top Alemite fittings on a T were an "upgrade" from grease cups in the late teens and the twenties. Alemite switched to modern Zerk fittings after they were patented in 1929.
Thanks for the information. I'll start searching for a an Alemite grease gun.
I put some brakes on my 47 Hudson a while back and that was the only old car I ever took a front hub off that wasn't completely filled with grease. I put some bearings in a hay rake last week and my boss wanted me to fill that hub with grease. Whatever. I just pack the bearings. I took apart a Model A rear axle one time and the whole thing was full of grease. I wondered why no oil drained out when I took out the plug. Guess somebody got tired of oil leaks.
I was always taught to just pack the bearings. Anything else was just a waste of grease. I always do smear a bit of grease on everything else inside of the hub just to keep any rust from forming. This has worked for me for 60 years, right or wrong. JMHO. Dave