Crawford Lathe's 4 spd drive box woes...

[KeeponDragon]

So I was turning a piece of stock for yet another project, and noticed that the Dominion Auto-Drive that the lathe is equipped with, has started to weep oil.
My first assumption is its coming from one of the shaft seals.
Has anyone ever worked on one of these gear boxes?
Or made attempts to source parts?
A bit of google-fu so far has come up empty...
But I'm still searching.
It's probably best I pay some attention to it before it fails catastrophically...It's a cool chunk of history...and still functions well.

 

[trevj]

I think your best bet is going to be to skip trying to find Maker's info, and measure the parts yourself, and have a chat with the guy at a bearings and seals house, such as BC Bearing.

A digital Caliper would be very handy, take measurements in both Inch and Metric dimensions for the seals, and try not to wince, if they mixed both systems. That happens a LOT with bearings, two Metric dimensions, typically the OD, and thickness, and an Inch specified ID dimension. With some luck, they bought in a catalog seal, rather than having a custom oddball one made up for their specific use case. Outside Diameter, Inside diameter (shaft size), and thickness, are the three dimensions you will need, to find a suitable replacement seal. Given a desire to not make things worse, before sourcing replacement parts, I suggest measuring the OD, as best can by eye-balling the caliper to the seal seat itself, directly measuring the shaft, and making a best guess as to the thickness, either by finding out what is actually available, or by whatever means you can come up with to measure the space taken up by the bearing and the seal through the casting of the case.

In a worst case scenario, you may be able to make an effective seal using a turned spacer with some grooves cut in for o-rings, or run grease, rather than oil, in the box, to reduce the flow of lube out through the compromised seal.

 

[Bandit]

Check the venting of the gear box, a plugged vent can cause leakage, temperature changes, longer run times, higher work load, could cause a bit of extra pressure forcing oil out.
But many, many hours of work and worn seal more likely.
There are sleeves available for some shaft sizes that can be installed in the case of a badly worn seal surface on a shaft. Sometimes the seal can be installed in a slightly different position in the housing to get a better unworn shaft contact, sometimes a seal can be installed backwards to achieve the same result. A double lip seal may also fit if not already used.
All easy to say, maybe hard to do.

 

[KeeponDragon]

I pulled it apart yesterday. All the measures a parts guy (me) could need recorded.
Upon inspection, my assumption is it's simply a matter of the unit's age.
Shaft is clean, no pits or large grooves...one minor groove to speak of...but it more or less buffed out with a little emery cloth.
The seal, is a double-metal-side, leather lip, spring reinforced piece. Definitely a robust design for the time it was designed.
The # on it went absolutely no where...but I'm not surprised...given the age...
These transmissions were made between 1940-something to the late 1960's...

So with all that...CR part # 12483 is the winner...under 20 dollars shipped to my shop.

I'll have to make a gasket for the flange the seal rides in, IF one of the many Caterpillar o-rings in my stash doesn't fit.
While I have it apart, I drained the oil, which wasn't terrible looking, just dirty...I couldn't find a vent anywhere, but I have a theory...
The selector levers, the shafts are near the top of the case. I wonder if there's a enough of a gap between the shaft and the housing to accommodate venting.
I don't know if grease would work in this type of gear box arrangement...
The one YT video I did find, the guy used 15w40 diesel oil in it. But good old 80w90 will pour in just the same...
Thankfully, it's got fill and drain plugs in easy to access spots. So if it doesn't like the 80 weight...it's a quick process to refill it.
I'll post pics later...

 

[KeeponDragon]

Old, double sided seal with # that no longer correlates to anything. Pretty decent quality to last at least 60 yrs...
Bearings aren't loud, there's no end play or radial movement in the shaft
New CR seal and a CAT oring to seal it back up.
There is a groove under the oring for it to nest into during reassembly...