Accurate Bearing Company 1-800-323-6548 you will need an industry standard number. There is a cross reference on this site that should have that info.

Sheldon

 

Thanks. Per the cross reference on the site, the bearing is NTN 6208LU. So one side of that bearing is open, and one side is sealed?

 

I don't have all my parts in front of me, but 6208 sounds right. I'm pretty sure all the ones I've seen are sealed on both sides, and have the snap ring.

I'm pretty sure I have a keyed clutch in my spares, if it would help I can go dig it out and look at it to confirm.

 

I'm not an expert on the old style clutches, so I would assume that is correct. Maybe someone with an older tractor will help us out.

Sheldon

 

Timken makes a 6208-RS, which appears to be the right size.

Interestingly, the keyed clutch as shown in the parts diagram I posted above doesn’t show a snap ring being used with the bearing, whereas the splined clutch does.

 

Thanks, but don’t go through the hassle. I’ll take a look at the reverse side of mine for comparison.

 

It's easy enough to pull the seal on one side of a bearing that is sealed on both sides. The trick is to take a small screwdriver, and stab the seal on the ID of the seal, not the OD, and pry it out.

 

Are you suggesting that with the clutch the bearing should only be sealed on one side?

 

Part # 91 is the shaft seal that can be changed externally.
There is another seal behind part # 90 clutch plate that is the big internal bearing to disc/plate seal. That seal replacement requires the transmission to be opened up and a snap ring removed to remove the clutch disc/plate, then the seal can be removed and replaced. You usually don't have to replace that unless the big bearing goes bad inside the transmission case.
Bearing # 96 usually has an external snap ring to hold it in place when the clutch is engaged. The snap ring is what makes the bearing press against the springs to put pressure on the clutch disc, otherwise the bearing would slide through the cam arm when it moves towards the clutch assembly during engagement. That bearing is sealed on both sides, some have a metal seal instead of a rubber seal. The metal seal withstands the heat and dirt better than the rubber seal does because it gets very hot there during operation.
Make sure spring # 97 is in good shape along with its washers. That is what helps release the discs when disengaged.
Make sure the shaft it rides on is good and cleaned off, use a piece of scotch brite pad or fine sand paper to clean it and make it smooth, then add a light coating of grease to the shaft and inside # 92 clutch hub to make sure it slides on the shaft smoothly and easily so the clutch engages smoothly and prevent a jerky engagement.

 

Thanks for the detailed explanation. I’ll make sure the spring is in good shape and that everything is cleaned up well like you mentioned.

Do you happen to have a part number for a bearing with metal seals? All the ones I’ve seen appear to have rubber seals. I did find another thread where it was mentioned that Richard’s recommended Nachi 6208-2NSE9NR, but it looks like it’s got rubber seals too.

 

Nachi NS/RS bearings have rubber/plastic seals,which seal better, but have a bit more friction than bearings with shieldsj.

Check out page 3&4 of this pdf: https://www.nachiamerica.com/content/downloads/deepgroove_onlinefinal.pdf
It indicates the codes used for the different seals/shields/grooves for their bearings, and which conditions each type of seal/shield works best for.

 

Thanks for that information. So I guess the question is what’s more important—-reduced friction/heat or better seal. Unless the rubber/plastic seal is going to wear out unusually fast due to the increased friction, I would think the better seal it gives would be preferred.

 

That is a high speed bearing so with the speed comes the heat from the friction. It is also subject to heat from the clutch. The heat can damage the rubber seal in a quicker time along with the friction wearing it, that is why some of the older bearings used the metal seal. Less heat and friction.
I would say use what ever bearing you can get. If you use the rubber sealed one, just keep an eye on it more than the metal sealed one for wear of the seal. If it wears out quicker, just replace it with a new bearing.
I have used both satisfactorily, I got longer life out of the metal sealed ones. The metal is more of a protective shield on them, they still have some high temp rubber inside of them to help seal them. It is just lower friction for the higher speeds and the metal shields it more from debris and some heat. They are usually more expensive.

 

So as expected, the bearing is torn to pieces. Any tips on how to remove it?

Also, my clutch clutch disk assemblies are different styles. If I look for an extra as a spare, are there any benefits to one over the other?

While I’ve got things apart, any suggestions on where to buy new internal springs, snap rings, shims?

 

Take it to a machine shop, they should be able to get it out for you.
The one clutch you have has a replaceable lining on it that is riveted to the hub, the other one is a bonded lining-glued fast.
The riveted ones are replaceable by drilling out the rivets and replacing the lining plus the the rivets with a special spacer tool to get the rivet set properly, there is also a steel spacer plate between the hub and lining.
The non replaceable one usually requires a new hub with the holes drilled in it but you can have the lining ground off with a surface grinder at a machine shop, then they can line up the lining and drill it for you so you don't have to buy a new hub, then all you would have to get is the lining, spacer, and the rivets to install it. You use 6 steel rivets 1/8 inch thick by 1/2 inch long.
Let a machine shop do it for you so the lining is set true and not out of round, they can set it up in a lathe so it will be even and true all the way around.

 

Thanks for the reply, but that’s definitely not the answer I wanted to hear. I know it would take a machine shop no time at all once they get to it, but the problem is the down time before they get to it.

 

You're correct, if they're any good, they will have a backlog.

Talk to the manager. Tell them you need the machine in service, and see if you can reserve a slot in their schedule. You might have to pay a deposit up front. Depending on what kind of work they typically do (IOW, how predictable their schedule is), they may be able to accomodate you.

 

Seems to me that by the time you pay someone to mess with that, you could just buy a whole clutch, new or used.

My tractor has the newer style and I have spares, ready to pop on. And new linings ready to repair a worn one. For me, time is more valuable than money in this case. So yes I have some money tied up in strategic spare parts.

The up side to that is also you can buy the parts when you find deals, or before price increases which are always happening with parts for older stuff.

Sheldon

 

I have zero experience with the bearing you're dealing with, and it being pressed to a shoulder isn't going to make getting it off any easier. I can tell you when I had to get a bearing and bearing retainer off the axle shaft of my daily I did it as documented in this how to (there are pictures, everyone loves pictures ). Thankfully with bearings being as hard as they are if you can get a small cut off tool in there you'll probably be able to crack the groove you make with a cold chisel. Good luck!

How-to: Replace M226 Axle Seal

You might be looking at this thread because you've got gear oil all over your back brake. You're gonna have to replace the seal. Before you get started with that if you've never touched the breather on your axle it's potentially clogged. The first thing you'll want to do is pull the breather on...

www.thenewx.org

 

Thank you all for the recommendations. I just bought a new old style clutch on eBay that has a new bearing and a new lining.

I also removed the seized bearing from my clutch with a cut off wheel. The outer ring came off pretty easily, but the inner required a bit more finesse. As shown in the pic, the shaft needs cleaned up from where the bearing seized. Is there any issue if I clean it up with sandpaper so a new bearing will slide right on? As you can see, I also nicked the Bellville washer, but the cut isn’t that deep so I think it’s fine.

The clutch with the seized bearing (forward side) is also missing the shim. What did the shim accomplish, and is it necessary? The clutch seemed to work fine without it. If I should get a shim, any recommendations on where to buy online? The cheapest I’ve seen is around $10, which seems steep for a shim. Also, any recommendations for a place online to buy the snap ring that holds the bearing on and the spring that goes inside the clutch?

Lastly, I pulled the bearing off the working clutch (reverse side) and it says HOOVER SEAL 208 and has Japan on the back side. Just thought I’d share that in case anyone was interested.

 

Is there any issue if I clean it up with sandpaper so a new bearing will slide right on?

Wow. That's as messed up as I've ever seen one of those!

I recommend care cleaning the residue of siezed bearing off. You don't want to end up with it out of round. That will cause accelerated wear the next time you use it. You also don't want to take too much. The bearing should be a fairly snug fit on there. Allowing it to slop around won't be pretty.

Do you have a lathe, or access to one? If you can chuck it in a lathe and gently go at it with a carbide tool, that should take it off cleanly while preserving the shape. You'd want to take off only the crud melted on to the surface. Then take a little emery paper or something similar to dress up the rest of the surface. But only a little, to preserve that snug fit.

 

No lathe and unfortunately no access to one. I’ll just clean it up the best I can, throw a new bearing on it, springs, clutch cam, etc. and keep this one in my tool bag as a spare for temporary use in case I have another bearing seize in the future. My property is a little over 2 hours away, so it sure was a hassle not having both forward and reverse operable. Having an extra will at least allow me to finish up.

 

Just to see what Nachi would recommend insofar as a bearing, I’ve been in contact with one of their reps. He asked me what temperature and RPM the bearing gets to. Any ideas?

 

That is a High Speed bearing, it turns around 3600 R.P.M.'s and is subject to higher heat, around 100 plus degrees and higher.
So you would want to go with either the Metal shielded like the 'Z, ZE' or the Non Contact Rubber 'NK, NKE' bearing. If you would use the Contact Rubber 'NSL, NSE' they would work but you will wear the rubber seal out a lot quicker due to the high speed and hotter temperatures of what the bearing will be subjected to.
That bearing would work but wont last as long and have to be replaced more often.

 

That is a really good question. Later I may have time to put a photo tach on mine.

Sheldon

 

FYI.

 

That’s what I am doing currently—putting together a complete assembly to have as a spare. So as you’ve suggested, the type of seal will be less of a concern.

So as you’ve experienced the contact seals have worked fine and lasted a long time. The drawback of having a rubber/plastic outer seems negligible.

On a related note, I wonder what the drawback to a shielded seal would be? Based on the table above, the primary drawback is a lack of waterproofing, which I wouldn’t think would be an issue with our Gravely’s.

 

Yes, rain, snow, washing - clutches get wet. I think that is one of the reasons GRAVELY went to the simpler trunion design. Less moving parts, no small parts, less places that need lubrication. They work very well.

Sheldon

 

You make a good point. I was thinking in terms of bearings that get submerged, but there are plenty of other ways water can get in like you mentioned.