MTFCA Forum

I noticed grease on my brake drums so I decided to pull a wheel and see what the seals looked like. A previous owner installed what looks like the neoprene seals. Both brake drums appear to have grease on them. Has anyone just changed the O rings and seals in these or will I need to buy a new set?
When I pulled the outer seal and the bearing oil ran out & there was no grease on the bearing. I assume the inner seal is bad. Is there any differences as far as the outer bearing area since this has a Ruckstell axle?

The seals are a standard type and just press into the aluminium housing. As for the O-rings, I'm sceptical of their effectiveness at sealing against the rough surface of the axle housing, so I use silicone sealant in that area.
I can't tell from the photo, but it looks like your axle keyway is very close to the lip of the neoprene seal. I've had problems with this and had to sleeve the axle to stop it leaking.

Also, if your axle housing is bent and the axle is off center it could cause wear on one side of the seal. When you take it apart, pull out the roller bearing and check to see if the axle is centered. It might drop a bit because the bearing is out but if you move the axle up and down or side to side, it should be centered enough that the bearing will keep it in place.
Norm

If you can find the correct size O-rings, by all means replace them. You may find it necessary to buy another set of new seals though.

Before you install the new outer seals, dress and lightly lube the tubes that they slide over to remove any steps or burrs that might cut the seals. Also dress and lightly lube the axle shaft surface that the seal bears on. I also covered the axle keyway with a piece of electrical tape so that the seal would slide over the keyway without risk of cutting it. Pre-lube the seals and verify that the seals slide on all the way so that the axle key and keyway don't bear against the seal and tear it up.

In my experience, the modern inner and outer neoprene seals work so well that I don't add grease to the outer Hyatt bearings after their initial packing and installation. When I first installed them on my 1924 I continued to add grease, all it did was get pushed past the outer seal O-rings and made a mess like you experienced.

I can't tell you about those outer seals because I haven't used them. I use the stock felt washers. I suppose too much grease in the Hyatt bearings can be a problem, but I believe the usual mess is caused by rear axle oil leaking past the inner seals. I was told to install the neoprene inner seals with this product. I did, and so far they have not leaked again. If you have an older rear axle with the filler hole too high, keep the oil level an inch below the hole.

Possible causes for leaks...

1. Worn-out Hyatt bearing, or bearing sleeve, or axle shaft. Wear in any or all of these allows the axle to operate "off center", beyond what the seal can allow for, causing a gap between the seal element and the axle shaft.

2. Too much rear end lube. Remove the fill plug and see excess what might drain out.

3. The use of axle shims. The shims tend to migrate upwards, towards the seal, where they tear into the seal and destroy it.

4. Bad inner seal

5. Just a plain old worn-out outer seal...

A missing or displaced transmission driven plate plug can also be a cause of the rear axle overfilling on it's own by engine oil migrating down the torque tube.

Thank you all for the responses.

The oil that came out appears thinner than I expected. I would say it more closely resembles engine oil than 90w or 140w gear oil. That makes me think that there is a seal leaking and filling the rear end. I did not check the level before pulling the axle seal.

I lowered the end of the axle I was working on last night onto a jack stand before I went in the house. Tonight when I went into the barn I realized that this wasn't a smart move. Here is a picture of the differential fill plug. This looks like it's the "low" plug.

The oil that came out appears thinner than I expected.

That would be engine oil leaking out at the ball cap and running down inside the tube to the rear axle. Keep your U-joint packed with grease.

Steve Jelf wrote: ↑

Wed Aug 02, 2023 11:58 pm

The oil that came out appears thinner than I expected.

That would be engine oil leaking out at the ball cap and running down inside the tube to the rear axle. Keep your U-joint packed with grease.

I had that problem on a former car. Kept ball cap packed all the time. The oil just helped to liquify the grease that much quicker. Keeping the crankcase oil level at the halfway point between the two petcocks gave better results so I had to have a sight glass to be sure to keep it there.

TWrenn wrote: ↑

Fri Aug 04, 2023 9:44 am

Steve Jelf wrote: ↑

Wed Aug 02, 2023 11:58 pm

The oil that came out appears thinner than I expected.

That would be engine oil leaking out at the ball cap and running down inside the tube to the rear axle. Keep your U-joint packed with grease.

I had that problem on a former car. Kept ball cap packed all the time. The oil just helped to liquify the grease that much quicker. Keeping the crankcase oil level at the halfway point between the two petcocks gave better results so I had to have a sight glass to be sure to keep it there.

I'll do that. Am I supposed to use any special grease in that area?

Parts came in from Lang's today. Working on degreasing stuff and cleaning the brake pads. After cleaning the outer seals everything still looks undamaged and pliable. I'm going to go ahead and replace the inner seals and axle sleeves while I have it apart.

I myself, and most fellas, use the red stuff called "Red 'n Tacky" in the U-joint ball cap. If you've got it apart for whatever reason, pack it full before reinstalling the driveline. Othewise, invest in one of Lang's large grease cups with the zerck in it, and give it a good 30-35 pumps from your grease gun with the same Red 'n Tacky grease. Yes, 30-35...if you're uncertain if there's any grease in it at all. You can take the little plug out and peek inside to get an idea. Every oil change I give it another 20 pumps give or take and never any problems.

I have replaced the inner seals and bearing sleeves. It's back together. The passenger side outer bearing still had grease in it, so that was a positive. Thank you all for the info.

I have replaced the inner seals and bearing sleeves. It's back together. The passenger side outer bearing still had grease in it, so that was a positive. Thank you all for the info.