TO20 leaking at the front crankshaft seal

J3ST3R0331

New User
Hello all. So I've begun taking apart my to20 searching for "the leak". I think ive narrowed it down to the front crankshaft seal, but I have some questions for the pros/experienced. I'm new to tractors (just picked this one up last week)so I apologize ahead of time for leaving out key info.
If the front seal is leaking, is it probable that my crankshaft bearings are bad? My oil is gray and I am assuming that I have severe metal wear...somewhere. the tractor ran when I pulled it into the garage... barely, but it runs. I drained the oil but have yet to drop the pan. The crankshaft main pulley seems very loose and wobbly.
Thoughts? If I need to get a bearing kit, should I buy the std or +.001/+.002/+.003 etc etc?
Should I replace the front seal and see what happends?? Thafs what I was hoping to do, but I also dont want to be back at this point after I get it all painted up pretty and reassembled.
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So, you may or may not have a few issues here. A leaking front seal could be the result of the loose front pulley and dirt getting into the seal behind the pulley. Support the tractor behind the engine at the transmission and remove the front end. A simple way is disconnect the tie rod and radius arm from one side, then remove the four bolts from the front axle housing and swing the whole axle assembly around the front of th tractor giving you room to work. Or remove the whole thing.

Get a puller and remove the front pulley, inspect for grooves which would be wear and contribute to the leak. Then you can pull the front cover off to get at the front seal.

Let us know how you make out. And if you don?t have one get a service manual
 
Thanks, Tom. I'll work towards that. Looking ahead, if bearings are needed, how do I decide what set to get? Obviously I dont want to take this path but I am trying to understand what decides this.
 
The gray oil could be signs of coolant in the oil. Those blocks are known for cracking in the web between the cylinders, but could also be the head gasket or orings at the bottom of the cylinder liners. Or it could just be nasty oil from not being changed, stored out side, or run cold without a thermostat.

As for bearing wear, if it has little or no oil pressure at warm idle, that is a typical symptom of bearing wear or failure. Also deep knocking, worse under load indicates excess bearing clearance.

The loose front pulley is concerning. If it has run loose long enough to be wobbly on the shaft, good chance the end of the crank and the inside of the pulley are worn to the point it won't stay tight. The pulley can be replaced, but no easy fix for a worn shaft. If you end up pulling the engine be sure to check the end of the crank and keyway for wear before investing in having machine work done on it.

As for undersize bearings, going back with undersize bearings on a standard crank is asking for trouble. Problem is the crank journals don't wear round, they wear more on the top and bottom where the load is greatest, leaving the sides close to original. The undersize bearings may be too tight, resulting in not enough oil clearance and seizure. You will need to measure the crank, check to see if it has been previously turned, check it for out of round, check it for wear tolerance.

All this information will be in a shop manual. If you don't have one, it will be a valuable investment.

A lot also depends on what the tractor will be used for. If you are building a working tractor, everything needs to go back done right, no shortcuts. If it's for show, parades, light work, you might get by with a new seal, clean the pulley and shaft, maybe find a better used pulley, Locktite it to the shaft and see what happens.

Since this tractor is new to you, there is an advantage to patching it up and using it a while. That will give you a chance to put it through the motions, find all the problems, make a decision as to how far you want to go. Then if you do go into it, fix everything at once instead of getting the engine back in and discovering more problems. Best to only have to split it once!

Keep us informed how it goes!
 
Hi, Steve. Yes, I am positive this is a 20. The block is stamped with "z120A600" and the tag was still readable after I got some paint off. 1949!! Pretty awesome!

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Given the vintage of your Tractor, as well, you are so close to the Governor, Camshaft /Crankshaft sprockets and drive train, it would be time well spent to remove, Inspect components behind the timing gear cover.
These pictures are of a Z134...probably not he engine you have, but gives you an idea.

Your machine your $$$$$'s

All the best:

Bob...Owner of various colored Tractors:
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Hi, John. Thanks for the comment and advice. You're right. I will definitely be taking a look into all the above said.
 

Thanks for the info, Steve. Great points. I'll get a book. I did not realize they had all this detail in the parts book.
 
*UPDATE*
So I got the front end off and down to the timing chain cover. When I removed the cover, I found the Oil Throw Off Washer leaning against the timing gear just as shown in the picture. Its half gone, so I think this explains my gray oil. Does anyone know what would cause this?

Second, I noticed that I'm missing the crankshaft starting jaw. I pulled off (I forgot to mention this earlier)a WM3 loader from this tractor. The pump was mounted direct drive to the crankshaft with a splined shaft. In place of this jaw, there was a bolt head and an oversized nut to not allow the bolt thT was probably too long to fit into the crankshaft to thread in all the way...Hack job install. Anyways, the jaw washer was also missing. The pulley came off with ease. I am very surprised thT the only thing thT is supposed to keep oil from leaking out is this fabric seal around the pulley.
Lastly, I can now see that I have a broken(previously attempted to be welded/fixed) front axle support assembly. Was not too happy about that. More to follow but please give me your opinions and 2 cents!
 
The broken ear on the block is a serious problem. Not sure if that could ever be repaired successfully. There are a few weld shops around that can braze cast iron, but more say they can than really can, still an iffy situation at best.

Those tractors didn't handle FEL's well. Between the weak front end and no power steering. Having the broken ear will be an ongoing problem with or without the loader.

I suspect the oil slinger washer split from the pulley being run loose.

If you are going back together, be sure to look behind the governor disc at the ball cage. They are prone to break.
 

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