Rear axles bearing grease looks like oil

Rata Road · Post by **Rata Road** » Tue Nov 14, 2023 3:56 pm

New arrival so no previous rear end history- 1914 small drum.
A couple of weeks ago I removed the rear bearings and repacked. I also removed the axle sleeve, cleaned it all out and fitted a modern inner seal. I used a new felt axle cap washer from a packet stating "axle cap washer" plus new steel washer and new metal cap.
Driven approx 30 miles.
I noticed heaps of gunk running out of the rear brake drum on one side.
Pulled apart to find everything soaked in oil more then grease?
I also discovered the felt washers center hole is too big for the axles hence it didn't seal. That I cant rectify but I am confused as to why the bearing and brake drum etc is covered in a slightly thick oil and no grease to be found anywhere.
Question - does the grease turn to oil when it isn't sealed in the cavity correctly?
I dont know what oil is in the diff (I just checked the level) but I did fit a new inner seal. Is it possible the diff has a light oil in it and this has run up the axles and diluted the grease in the bearing and pushed it out through the poor fitting felt washer?
Your thoughts?

Post by **Jerry VanOoteghem** » Tue Nov 14, 2023 4:04 pm

Your '14 should have the rear end filler plug located roughly along the centerline of the axle housing. That does not mean that rear end lube should reach the filler plug hole. If so, you've got way too much lube in there and it will leak out. Later housings have the plug much lower, probably for this reason. So, when you checked the level, how close to the filler plug did you find the lube?

Also, not uncommon to have engine oil leak out of the 4th main, flow down the torque tube, and overfill the rear end. Usually happens with a well worn 4th main, or a missing plug in the transmission output shaft.

Post by **TXGOAT2** » Tue Nov 14, 2023 4:08 pm

Grease won't turn to oil unless it gets very hot or is of very poor quality. The general tendency is for grease to thicken somewhat over time. I would guess that motor oil is getting into your rear axle somehow, which will thin out grease to a semi-liquid. This can happen with a T.
"Gear oil" is a different matter. It is normally a more or less thick fluid, and it usually thins somewhat when warm. If your axle has gear oil in it rather than grease, or a mixture of the two, the leaked fluid might have the appearance you are seeing.

Post by **TXGOAT2** » Tue Nov 14, 2023 4:10 pm

Old axles may have most anything in them... gear oil, very old, sludgy grease, motor oil & grease or gear oil mixed, clean grease, water/grease emulsion, etc.

Rata Road · Post by **Rata Road** » Tue Nov 14, 2023 4:23 pm

Great feedback guys, I just searched what your saying and I'm thinking the diff is over fill due to the filler hole being higher on this era and the level should be about 1.5 " below that. Easy trap to fall into.
Too high in oil and probably running up the axle and flushing out the bearing. I think I will suck some out the diff and ensure I have the correct level and then when some correct oil arrives from the USA I will suck it all out and start fresh.

Post by **Craig Leach** » Tue Nov 14, 2023 5:11 pm

Hi Kevin,
What modern inner seal did you use, which outer felts did you use? There are two felts on the outside. one between the washer & cap the other between the cap & the hub( dust seal) Over filling will definitely cause a leak as the inner seal may not stop that much gear oil. the outer felts
will only stop grease. The felt inside the cap should fit snug on the axle.
Craig.

Rata Road · Post by **Rata Road** » Wed Nov 15, 2023 3:12 am

I think I got the inner seal from Macs a few years ago, modern style.
Today I have refitted the old felt seals that I took off a couple of weeks ago as they are the correct tight fit on the axle. I have ordered a heap of the correct size felts to have on hand, I'll fit new ones when they arrive.
My box arrived from Langs this arvo with the correct diff oil so I sucked out the diff oil and replaced with new oil to the correct level for the higher bung (1.5 inches down).
Craig I can't figure out where the 2nd felt goes that you speak off? I have watched a few youtube clips and nobody else used two?
Be interesting to see if the bearings stay greased this time.

Kerry · Post by **Kerry** » Wed Nov 15, 2023 3:18 am

The second felt seal go's in the brake drum and runs on the tin cup that is holding the first felt seal.

Post by **TRDxB2** » Wed Nov 15, 2023 10:56 am

Matter of semantics - when is oil called grease - You may have the right stuff
"Rear axle fluid " that suppliers sell for Model T's

Post by **jiminbartow** » Wed Nov 15, 2023 11:06 am

Sometimes, over the years, if the drive plate and driveshaft bushings are worn, oil from the crankcase can leak past the fourth bearing at the tail end of the engine and migrate to the differential through the drive shaft pipe connecting the rear end with the engine, thus, thinning out the rear end gear oil. If the thick gear oil gets thin enough, it has no trouble getting past the pumpkin seals and out through the axle shafts. Jim Patrick

Rata Road · Post by **Rata Road** » Wed Nov 15, 2023 1:51 pm

Thanks Frank, I have never seen a seal in the position on any of my cars so I will put them on (I have a heap of them) when I remove the wheels to fit the correct new seals.

Yes I used 600w grease, exactly the same as the pic posted.

I sucked out most of the existing oil/grease from the diff so i could refill to the correct level with the new 600w that arrived yesterday and the stuff that came out is in good condition, no thinner than the new and clean looking so I don't think the engine oil is running into the diff. I turned the axle over between sucks to keep it mixed.
I wish they had a drain bung!

DickC · Post by **DickC** » Wed Nov 15, 2023 3:54 pm

It sounds like oil is seeping passed the fourth main. Check the amount of grease at the universal. I have found that packing this will help to keep oil from going down the torque tube.

Post by **speedytinc** » Wed Nov 15, 2023 4:39 pm

"I think I got the inner seal from Macs a few years ago, modern style."
Seal failure:
In order for a modern lip seal to work, the shaft must be smooth & pit free. You would have had to get a view of the surface where the seal rides.
Depending on what was used previous, one can expect pitting @ a minimum & a horribly chewed surface from the leather with finger washer tensioner.
If yo used the black neoprene type seal that looks like a ahmash hat, The seal surface is about 1/2" wide. These seals will grab onto the axle shaft & destroy themselves.
Either way, Pull the bearings & inspect the seals. See if they are still functional.
The outer felt washers fit tight on the axle shaft. Oil the contact surfaces before installing.

I think you realized you overfilled the diff.
Keeping the level well below the axle tubes will keep the lube from washing out your packed bearings & not allow the lube from running into your brakes. If you are using axle shims, they can work into the felts, cut them & cause the outer seals to fail.

Allan · Post by **Allan** » Wed Nov 15, 2023 4:52 pm

Kevin, your comment earlier that the felt seal hole was too big for the axle shaft probably indicates that the felt you installed was the one that goes in the relief in the hub.
Sometimes the shoulder in the hub that retains this felt is so worn/damaged that it almost seems insignificant and its purpose is overlooked.

Allan from over the ditch.

Rata Road · Post by **Rata Road** » Wed Nov 15, 2023 5:28 pm

John, there was no existing inner seals in place before I fitted the ahmash hat as you call it. But these new seals have only been in for 2 weeks and hardly any miles, Maybe the oil from the diff has got around the outside edge of the seal.

Alan - I didn't pick up that the new felt washers I used were very loose on the axle when I fitted, I just read "axle outer seal" on the packet and put them on. Wont make that mistake again.
Hence I have ordered a heap of the correct size and will fit some when they arrive. In the meantime I have reused the old ones I removed 2 weeks ago, at least they are a tight axle fit.
I don't understand where these larger centre hole washers go, I thought I did when someone said earlier they go between the metal cap and inside of the wheel but now you say they go in the relief of the hub? Thats got me more confused.
As I stated nobody fits these mysterious felts on any youtube clip I watch?

On an interesting note I removed the other side wheel also yesterday because I had also fitted the large centre hole felt on that side and there was no signs of any leakage coming through from the diff past the seal. The outer bearing showed oily signs so I cleaned that and greased it up plus I changed that axle seal out for a second hand tight fit in the meantime also.

I looked at the sucked out diff oil/grease again just now after it has settled over night and its clean and consistent. This would indicate there is no engine oil leaking into the diff unless its settled at the bottom of the diff head where my suction pipe couldn't reach.
I think the high diff bung location has encouraged someone before me to overfill the diff. Well I hope that is the cause.

Post by **speedytinc** » Wed Nov 15, 2023 5:38 pm

The right side gets more oil flinging & churning from the gear teeth. The left side carrier is being pushed against the thrust washer pack, allowing a minimum of lube to get past.

Check those inner seals & see if they are still intact. It doesnt take many miles to fail.

Think about it.
If the inner seal was doing its job, there would be no leaks, even when overfilled.
I am fairly confident you will find the seal shredded or de-laminated from its backing washer.

Post by **DHort** » Wed Nov 15, 2023 11:26 pm

: modeltrearhub.jpg (10.44 KiB) Viewed 5576 times

Kevin

Look at this hub and you can see the groove where the second outer felt seal goes. Soak it with just enough oil to hold it in place.

: modeltrearhub.jpg (10.44 KiB) Viewed 5576 times

This is the outer axle housing cap and the felt protects this cap from being rubbed raw by the hub. Too many people forget to install
the felt in this location. I hope this clarifies this for you.

Kerry · Post by **Kerry** » Thu Nov 16, 2023 12:35 am

Rata Road · Post by **Rata Road** » Thu Nov 16, 2023 1:39 am

Thanks guys that clarifies for me.

Its only the left side that I am having trouble with looking from the rear of the car or passenger side (RHD).

I See exactly where that felt goes now, brilliant I will pull the wheels off again tomorrow and fit these to each side plus I will check the new modern seal just fitted as suggested, like you say it the only place the much can come from. Lucky I ordered 2 more modern seals which arrived with the 600w yesterday.
Whats the best way to remove those seals, long wire with a hook on the end?

Thanks again for taking up everybody's time.

Kevin

Allan · Post by **Allan** » Thu Nov 16, 2023 7:01 am

Kevin, in NZ it will be te left side that leaks. Same here in Australia, because that is the lower side due to the camber in the road surface.

Allan from down under.

Rata Road · Post by **Rata Road** » Thu Nov 16, 2023 2:43 pm

Of course, that makes sense Allan.
Thanks again

Post by **KeithG** » Thu Nov 16, 2023 11:13 pm

Kevin, In one of your posts above, you posted:

"I wish they had a drain bung!"

Our friend Stan Howe (RIP) who used to rebuild Ruckstells, used to tap a drain hole in the right side axle housing to drain the old grease / oil. I think it was a 3/8" hole & fine thread using a plug with a square head on it. I put those in two of my Ruckstells and they work great.

Keith

Rata Road · Post by **Rata Road** » Fri Nov 17, 2023 1:57 am

Keith if I ever have one of the Diffs out of any of my cars a drain bung will be fitted as you describe.

Post by **DHort** » Fri Nov 17, 2023 4:07 am

Boy Kevin

I do not know if I would install a drain bung unless I was lubricating my differential with wine or beer.
Drain bungs are easy to pull out.

I have a drain plug that Adam Doleshal installed in mine. Makes it easier to drain the oil.
I think it is 3/8 inches, but 1/2 inch would work too.

Rata Road · Post by **Rata Road** » Thu Nov 23, 2023 3:42 pm

Looks like I have it beaten.
I read that applying a sealant to the inner face of the outer edge of the modern neoprene style seals (that fit inside the rear wheel bearing) can stop the leakage getting past.
So I done that, pushed them in firm, then inserted the wheel bearings to hold the axles in a central position and left it for 48 hours to set before reassembly.
So far so good, its been about a week and about 50 miles with no visible sign. I will confirm it when I removed the drums to install the new felt washers when they arrive.
[attachment=2]DSCN4525.JPG[/attachment]

[attachment=1]DSCN4528.JPG[/attachment]

[attachment=0]DSCN4529.JPG[/attachment]

BobUkPipedream · Post by **BobUkPipedream** » Fri Nov 24, 2023 3:51 pm

What does everyone think of the modern outer seals that replace the old outer axle caps? I have the aluminium machined ones that have o rings to fit on the axle casing and with a neoprene seal to fit to the axle.

Allan · Post by **Allan** » Fri Nov 24, 2023 4:58 pm

I like the alloy machined seal caps with the O ring and modern lip seal on the axle. However, it is vital that the section of axle that the lip seal runs on is not damaged in any way, or the seal will not last long.

Allan from down under.

Post by **DHort** » Sat Nov 25, 2023 1:54 am

I do not know why anyone would use the old outer seals, when the new outer seals seem to be so much better, except for cost.

Rata Road · Post by **Rata Road** » Tue Dec 05, 2023 2:19 am

Well that didn't work.
Removed the wheel after a bad leak and look what I found.
Looks like the axle might be bent (check the video), do you think this would promote the leak?

https://www.youtube.com/watch?v=u-PBQ3ZDlfo

Thanks
[attachment=0]DSCN4581.JPG[/attachment]

Allan · Post by **Allan** » Tue Dec 05, 2023 6:45 am

Kevin, most of the run-out in the axle is in the threaded end, and is not likely a contributor to the oil leak. tThe colour and consistency of the leaking fluid is way off. It looks very likely you are getting engine oil in the mix. I would be checking the contents of the universal joint ball housing.

Allan from down under.

Post by **Mark Nunn** » Tue Dec 05, 2023 8:09 am

I scooped about a quarter pound of grease out of this brake shoe. It doesn't look like that anymore, having done a proper rebuild.

Post by **speedytinc** » Tue Dec 05, 2023 8:28 am

Hard to tell for sure from the picture, but the cup doesnt look on all the way.
It takes a BFH to compress the felt seal & get the cup on all the way.

When you re-attend to it, pull the bearing & insure your inner seal is still in tact.

Post by **TRDxB2** » Tue Dec 05, 2023 11:34 am

Allan wrote: ↑
Tue Dec 05, 2023 6:45 am
Kevin, most of the run-out in the axle is in the threaded end, and is not likely a contributor to the oil leak. tThe colour and consistency of the leaking fluid is way off. It looks very likely you are getting engine oil in the mix. I would be checking the contents of the universal joint ball housing.

Allan from down under.

In agreement with Allen. You may be missing the plug

Post by **RajoRacer** » Tue Dec 05, 2023 11:35 am

Well, that's a mess ! Couple of pointers from casual observation - your rear shackles should be installed with the inside twist oiler on top and the rear on the bottom - opposite of they are now for ease of oiling (still have to get under the car to get the inside one !) & when installing the brake shoes, attach the springs with the hook from the inside to assist in holding the shoes towards the backing plate - just suggestions.

Rata Road · Post by **Rata Road** » Tue Dec 05, 2023 2:41 pm

Thanks guys, good suggestions.
If it is engine oil seeping through is it possible that this oil only makes its way to the outer axles? The reason I ask is the oil/grease level in the diff is about 2 inches below the filler (1914 Diff so higher hole) and is still looking like the new 600w I put in and no signs of engine oil which implies if it is coming down the tube it isn't settling in the diff head.

What's the process to check and repair if oil is leaking from the trans?

Post by **speedytinc** » Tue Dec 05, 2023 2:55 pm

If the output plate plug is missing, the plate needs removing. 6 bolts. @ the very least, the motor/trans has to be lifted off the crank case a bit.

The easier to repair is a sloppy 4th main. Replace. .0015-.002" clearance.
If you have a transmission screen, it concentrates on the 4th main. It can be turned 180 degrees to limit some of the concentrated oil.

Rata Road · Post by **Rata Road** » Wed Dec 06, 2023 4:45 pm

Thanks Speedy. I'll turn the screen around.
I've filled the front grease bowl and monitor the result.
I'm not sure about lifting the motor/trans off the crankcase?

Post by **speedytinc** » Wed Dec 06, 2023 5:02 pm

Rata Road wrote: ↑
Wed Dec 06, 2023 4:45 pm
Thanks Speedy. I'll turn the screen around.
I've filled the front grease bowl and monitor the result.
I'm not sure about lifting the motor/trans off the crankcase?

To be clear, the 4th main gets rotated for the big lube hole to point down.

Lifting the motor off the crankcase a bit is the minimum to get the drive-plate out.
It may be more realistic to pull the motor & remove the crankcase.
Resealing is tough with just a lift.

Rata Road · Post by **Rata Road** » Thu Dec 07, 2023 1:15 am

I cant turn the screen around due to its shape?
I fitted 5 small rectangular magnets to the rear of the screen, that might slow the flow in that area. I also fitted 2 neoprene seals squashed together on the offending wheel. That plus filling the front bowl with grease and I will see how this goes.
Just went for a 40 min drive and there is no signs of any leak yet, would have been dripping out by now.
I will also monitor grease/oil level in the diff.
Its been interesting, thanks again for everybody's time.

Rata Road · Post by **Rata Road** » Thu Dec 14, 2023 1:26 am

Looks good so far. Been for 5 long drives of approx 40 mins each and not a single drop even when wiping finger under the brake drum.
Maybe it was a combo of the things I tried last time, just to refresh -

2 neoprene seals fitted together
New axle end felt washer fitted.
Front ball filled with grease
5 magnets placed at the rear of the oil screen to reduce the rear flow.

It will be interesting if it lasts long term plus I will monitor the diff contents going forward.