MTFCA Forum

This past weekend I was thoroughly inspecting my 1923 touring for any loose bolts (in anticipation for summer and touring). When I came to my rear right axle nut, I realized it had somehow loosened up. As I was pulling the cotter pin and applying my torque wrench, I realized there was a good amount of oil covering the nut. After pulling the wheel off I was welcomed with the sight of a rear axle oil leak.
Back ground information:
I have just recently finished a frame off restoration of this car, and it only has ~1,200 miles on in since the engine was totally overhauled by a reputable builder, and the rear axle rebuilt per the club manual. Both of the axle shafts were original dimensional size, had no signs of wear, and were fit with inner neoprene axle seals and ford felt on the outside. I have been filling the differential with the 600wt from Langs.
I removed the differential plug and some oil did seep out, (6 inch diameter puddle of oil over 24 hour span), but the consistency was thick, and did not seem to be diluted by the engine. I though if the the forth main was leaking, then oil would come out if I pulled the lower plug used to access the driveshaft rivet. None came out.
What do you guys think is the problem. Could I have just accidentally pumped too much oil into the housing and plugged it up before it had time to leak out? I have a hard time thinking that it is the 4th main given that the engine was fully rebuilt 1,200 miles ago, has the appropriate oil level, and does not have any severe vibrations or knocking that would indicate an engine issue.

Thank you for the ideas,
Joshua

What did you use to glue your inner seals in places? Some sealants/ gasket makers are not compatible with gear oils.

Stephen

These wonderful neoprene cup inner seals (if what you used) grab too much & too tightly to the axle shaft. I have never seen one that wasnt destroyed by itself after only a few miles. I find that cutting the unnecessary long outer band to the first bead makes them functional.

Even if the inner seal fails, your outers are not doing the job. I successfully use the simple felt & cup seals. They must be pounded in all the way until they wont go any further & pre oiled to not wear out the felt sealing edge.

As for a loose wheel. They typically take several torqueings before they take a set If you dont lap the tapers. 80# or so. I use a 3' breaker bar.
If you used shims expect it forever as they pound & flake. Could the shim have worked its way into the outer seal? Typical situation. Do not use shims. Use or modify axles for more length during the rear end rebuild.

As far as your engine re-builder. There are a lot of guys that claim to know what they are doing who dont. Conjecture, I dont know the credentials of your guy. I do a lot of rework on improperly done motors. The clearance between the output shaft & the Babbitt 4th is .0015- .002" Buying the closest size to fit dosent. They need to be custom machined for proper fit. That needs to be on a clean, squared up shaft, not to mention the concentric running of the output. To few even know to check the run out, much less fix it.
The addition of a transmission screen concentrates a lot of excess oil right @ the 4th main. Looser fit, more oil bypass. A sloppy 4th main can be Turned 180 degrees to put the lube hole down & lower the excess oil flow.

Steven, I used the generic permatex that I used on the engine. Perhaps this could be part of the problem. Should I use a sealant for differentials, or do you recommend a specific sealer?

John, when I pull the seal out I will look at the fit of the seal to the axle, this may have been a contributing factor along with the wrong sealant? As for the rear axle and wheel. I am not running with any shims, the nut just loosened up a little since there are only a few miles on it. The wheel still required the hub puller to remove. In response to the engine re builder, I have only seen positive reviews regarding his work on this forum, and he does all of his Babbitt work and machining in shop. I should also clarify that he did the machine work, and I assembled the engine per his instructions and Mike Benders videos. If I remember right, the outrun was only a few thousandths, which to my understanding is acceptable. I am also running one of the transmission screens, I will look into slightly enlarging the rear holes per some posts on this forum. I have noticed some oil leaking from under the inspection cover there, so that is probably not helping.

Is there a way to check the 4th main without removing the engine or rear end? Additionally, is removing the universal joint plug from the bottom side of the drive shaft a bad way to check for oil, or is the quantity too small that it would not leak?

Thank you for the help,
Joshua

I use the permatex gasket maker that is specially formulated for gear oil. It comes in a green tube. I have never had a single issue with axle leaks since I started using it. I have about 7 thousand miles on my 26 coupe since I installed my ruckstell using the Special permatex and the inner seals are still doing well.

Stephen

Other than leaving the u joint pin plug out & running, I doubt you would see much or any oil running out.
I use ultra black silicone to glue in the inner neoprene seal. You do gotta reach in & clean away all the grease with brake clean.
You would have to pull out the 4th main to really access the clearance, a good 4". That means removing the rear end or sliding the motor forward.
The situation would have to be more obviously bad before I would go that far. Pull the big grease cup & look @ how much oil has actually diluted the grease. Another option is to use a heavier grease like disk brake molly that gets thinned with the extra oil.

You might consider adding felts between the inner bearing and the seal. Langs 2511F. Like wearing a cotton glove inside your unlined leather glove. Not necessary, but adds another layer of protection.

You might consider adding felts between the inner bearing and the seal. Langs 2511F.

Not a bad idea, but they sure are a booger to install.

Steve Jelf wrote: ↑

Tue Apr 05, 2022 2:53 pm

You might consider adding felts between the inner bearing and the seal. Langs 2511F.

Not a bad idea, but they sure are a booger to install.

There is NO room.
The bearing actually touches the inner seal washer face floating between it & the outer seal steel washer. The extra felt washers (originally 3) would have to go in first, then the neoprene seal. Could be done, but, 1 proper inner seal is all thats needed.

I wonder if Josh is putting too much rear end oil in? It shouldn't come out of the filling plug at all. I never put more oil in the housing than just enough to touch my little finger, and I even wonder if that is too much? All you really need down there is an inch. I've been using SAE 140 gear oil for 60 years, and it has always done the job for me. I also stuff three of Lang's heavy felt seals down inside the housing, and yes, they are difficult to install.

Larry, when you say just enough to touch with your little finger. You mean reaching down into the housing? If that is the case, then I over filled. When I originally filled it, I filled it up to the plug opening as I thought that is what Ford recommended. Knowing myself, I may have squeezed the bottle a little extra prior to installing the plug.

Are you aware that small drum axles had a low & a high filler plug? Your 23, if correct has the low plug that gets filled to the bottom of the hole. If that housing has been changed to an earlier housing, filling to the bottom of the hole will way over fill. A quick look might be in order. The filler plug (high)
is above the bottom of the housing tube. The low plug hole is below the bottom of the housing tube.

I bring this up as an unusual possibility, to cover all bases. I have seen a lot of strange/incorrect stuff on model T's.

Joshua.
It would depend on year of the T, the diff needs to be a 1/3rd full by the book so early diffs has the higher filler plug which was the finger in the hole level, then in about 1919 USA and 1915 Canadian, Ford lowered the filler plug so that is the level height.

You might consider adding felts between the inner bearing and the seal. Langs 2511F.

Not a bad idea, but they sure are a booger to install.

There is NO room.

Yes, there is. Between the inner bearing and the seal you have lots of room, a little over 16".

Steve Jelf wrote: ↑

Tue Apr 05, 2022 10:17 pm

You might consider adding felts between the inner bearing and the seal. Langs 2511F.

Not a bad idea, but they sure are a booger to install.

There is NO room.

Yes, there is. Between the inner bearing and the seal you have lots of room, a little over 16".

INNER! Missed this detail. I stand corrected on your point. It is possible.
However, where are you "sealing"? The raw axle surface will chew up the ID of the felts. The ID of the tube? The felts normally run on the 1.062 ground bearing surface. To be effective the axles would need to be removed & ground smooth.(original axles) Repo's are already smooth. Practical fix??

Gator told me once the change of the location occurred in 1918.

Gator told me once the change of the location occurred in 1918.

Bruce says 1919. The Encyclopedia has pictures.

Looking at the differential, I have the lower plug, (it is just below the bottom of the axle housing), so I should be correct in filling the oil to the hole. To answer John's question, I am running original axles, so the surface is the rough steel, not machined like the new ones. Has anyone had success with the extra felts on an original shaft?

My plan is to check the u-joint grease. I don't think the engine is leaking, but I will check just in case. I will then remove the neoprene inner seals, thoroughly clean the surface, and install new neoprene seals with sealant that is intended for gear oil. Finally, I will run the differential with oil just a hair below the plug opening.

While looking on Lang's, I saw that they sell neoprene outer seals. Are these any good, or will they just help hide the evidence of a future leak?

How does this sound?

Thank you,
Joshua

I mentioned the felts earlier because I think I have them in one of my axles. I remember how hard it was to install them, but I put them in dry. I should have soaked them in oil first. My guess is the center of the felt gets worn out real fast and the felts become just a dam to prevent the oil from moving toward the wheels. I do not think very many people use them.

I have never been able to remove the axle housing caps without using a screwdriver or pliers, and end up ruining them. There might be a trick to it, but I do not know it. I switched to the neoprene outer seals and they are great. They come off easily, and go right back on again. Well worth the cost. I was taught to remove my front and rear bearings every spring to clean and regrease them. This way I can inspect them to make sure they are good for another season.

DHort wrote: ↑

Wed Apr 06, 2022 8:40 pm

I have never been able to remove the axle housing caps without using a screwdriver or pliers, and end up ruining them. There might be a trick to it, but I do not know it.

I use a pair of gear pullers.

The claws of a claw hammer are good for two things: pulling nails and pulling rear axle dust covers

I use my hooked end Cat bar - one needs a back-up block for large drum backing plates.