On early axles with the high hole I think filling all the way up to the hole is asking for trouble. Any particular level I should go for? I'm guessing just shy of the tube is best.
On my 1924 with the filler hole below the midpoint of the axle, I added fluid up to the bottom of the filler hole.
If your older axle has the filler hole at the midpoint of the axle, a quick survey of older threads indicated to fill up to about 1 to 1.5 inches below the filler hole (or just to the level such that when you stick your pinky finger in the hole, it just barely touches the top of the fluid.
1-1/4 pints is right.
It looked like an inch and a half below the hole would be just under the tubes, so I improvised this to check the level.
If you have enough for the ring gear to pick it up it will flow to the right parts. A little more wouldn't hurt. Yes keep it below the tube unless you are using it to oil the brakes. :0!
"Yes keep it below the tube unless you are using it to oil the brakes." Thank you for that, I needed a laugh tonight!
This subject has been beat to death in past posts as to the weight and quantity of oil. Originally 1.5 pounds of grease was injected the differential housings. The text says #2 but that is a bit heavy, #1 or #1.5 is just right. The down side of oil is it can leak out the ends of the axles because there are no seals. The outer bearings are lubed with a grease cup and the felt is in place to keep dust out. Many have used oil with out leaking problems and just as many with leaking problems.
No seals? There are if you know what's good for you. They used to be leather with springs. Now they're neoprene. There are also big felt washers that go inside the tubes. I used three on each side. One just outboard of the inner bearing, one midway, and one just inside the neoprene seal.
Not factory issue, but a T era accessory. Even some of the purists use them. They're a booger to get in.
After reviewing Ford parts books from 1915 through to 1927 there are no "seals" just dust felts. The procedure for inserting the felts in the housings was to prevent oil from leaking out the axle ends. The oil was usually from a badly warn rear transmission seal that allowed engine oil to enter the differential housing and filling it and it would leak out the ends. A quick jobber fix was to form a dam by inserting a quantity of felt washers in various locations. One jobber prefers one in near the inner bearing and two some where in the middle. Another jobber suggests all three just inside the outer bearing. A dam is a dam I don't think it matters where they go. The system of inner felts was used when too much oil was put in or too light of oil. The system of seals and felts are after market assemblies only. Originally grease was injected through the grease plug and there was no means to drain, grease wouldn't drain anyways. The housings were never intended to accommodate an oil seal as they were designed to use grease. There are many members with different opinions on differential lubrication, some have been successful and some have not. If somebody chooses to use oil, felts and seals that is up to them, I wouldn't
I've switched two cars so far to the inner neoprene seals with those rather price, hi-falutent modern outer seals on the end of the axle tube. Nice and dry. Did discover one neoprene fail on the left side of my '12 as I have it torn apart right now for a diff. oil change and replace the leaky seal between the two halves of the housing. Dirty work, but fun. Oh yeah, the left outer bearing sleeve also had an oblong crack in it, was close to completely falling apart. Weird. Just for the heck of it, here's a pic of one of the housings I painted with that famous Valspar rattle can paint. This stuff is great!
The Improved Car came with factory oil seals, Part # 2511 rear Axle Oil Retainer, and Part # 2511B Rear Axle Oil Retainer Washer.
This is the steel finger retainer and the leather washer sold now by vendors, but this new repro is not like the original, and the fingers are too sharp and extend over the narrow washer and can wear a groove in the axle shaft. So many do not use these, take caution if you do.
Service Bulletin June 1926
The preferred is what I use, the modern inner neoprene seal, it just simply works! Easy, just remove the outer Hyatt sleeve, fit the new seal, re-install the sleeve and Hyatt bearing and no leaks!
The late Ford seals work just fine. The problem with the repros is all the little fingers have too much tension on them and need to be bent back so they won't cut into the axle. They are only to keep tension on the leather, not the axle. I like the heavy inner felt seals that Steve mentioned. They are a bitch to get in, but you won't have a leak anytime soon. I recently put together a very early Ruckstell, and the Ruckstell side had room for the Ford seal.
The text refers to part # T2511 as REAR AXLE GREASE RETAINER as opposed to OIL SEAL. With the required 1.5 pounds of grease it would seem most unlikely that grease would ever leak out. However if a non mechanic did the dip test and found no oil on his finger would most likely put some oil in and that is when the problems would start. It didn't appear to be a problem for almost 17 years and millions of housings. And in 1926 it was installed only as a precaution against rear axle grease leaks. I still feel the design was not for oil just grease and then only as a precaution on the last models. I have a curious question with the grease retainer #T2511 does the retainer remain in a fixed position and the axle turn inside or does the assembly turn. It appears that with the installation it would cause the Hyatt to stick out a little. Figure #167 appears to be retaining the grease in the bearing as opposed to the housing. I have difficulty accepting the fact that 1.5 pounds of grease could ever migrate out the ends of the axles. Oil is a whole different thing. If a member chooses to use oil 80wt - 600wt then greater precautions would be required to prevent leaking. Oil was not a Ford standard and all the felts and seals were not a Ford standard they were all after market and jobbers. To say all these seals and felts are required, is only if you choose to use oil they are not required with grease. I use 1.5 pounds of #1.5 grease that is very creamy and offers good lubrication and will not migrate out the axle ends, there are no "SEALS" or felt dams required. The felt dams were only installed where there was other issues, where oil leaked from the engine or somebody inadvertently put in oil or too much oil or too light of oil, the felt dam was a jobber quick fix and not a required component.
Today we're not used to the lighter variants of grease, they're hard to come by. Oil finds its way into the differential and keeps it lubed - too many of the old rear axles we take apart are worn way beyond what the low miles they've actually rolled would cause in a more modern axle. Maybe the use of grease was one of the causes for much of the excess wear in original axles?
As always, what works for you and your T is the best.
For me, have always used 600wt heavy oil in the rear axle, except for the Ruckstells.
And using the modern inner and outer neoprene seals keeps the heavy oil from going to the wheels and emergency brakes.
I like the 600wt because am assured that the inner Hyatt's are getting good lube, and the outer Hyatt's I grease with cup grease according to the manual.
As for the Part #2511C (both the leather and the washer, these are named by Ford in the Parts and Price Books, "oil retainers".
Correct that Ford called in the manuals to use 'grease' in the rear axle. But also named 'fluid grease' as suitable too. (1922 Manual)
No doubt that many many Model T owners in the day had rear axle grease or oil leaks. That is proved. Here are some pages from a 1918 Fordowner booklet on the subject.
And this part of the article states how to use the big Donut felt washers, these were available back in the day to stuff into the axle housing to prevent grease/oil leaks too.
Just some more info on the subject
Ya But, what about how much rear end oil to use? Isn't there a difference in the height location of the filler plugs between early and late cars? This is a good topic to have straight answers for. For instance , how far below the filler plug on a 1913 rear end should the oil be?How far for a 1920 style rear end? Etc.
I should have added the question: Does Mark's response pretty well cover the oil level requirement? (Thanks Mark). And Steve I like your bent wire checker gizmo.
This is only an assumption. Ford probably received the assembled housings from the manufacturer and simply installed them and probably had no input as to what the lubrication was. The housings were probably received with skimpy maintenance requirements and Ford created its own. Some manuals and parts books refer to the seals as oil seals and some refer to them as grease retainers, some refer to the filler plug as oil filler and some grease filler. All of the leaking issues are aftermarket fixes. The later improved models refers to a grease retainer as a precaution and therefore it is not an issue that Ford dwelled upon as much as the aftermarket jobbers did, and still do today.