Flail Mower Grass getting sucked through the bearings on Mott F5

[goatchay]

FWIW, I read through the entire thread and did not see any mention of your having done any gearbox service on your mower. I mention this because your last pic in post #1 shows a square plug poking up toward the PTO shaft from the gearbox area.
I'd hate to see you go to all the trouble to refurb everything and accidentally forget to service the gearbox.
I'll leave it to the 'membership' to give advice on the fluid to use and the procedure(s) involved.
BTW, good pics and details of your work.
Here's an idea for a bearing cover to kick around. You can buy the magnetic metal 'dish' at most any auto parts store to hold small parts, screws, etc. Could you adapt one of those or similar preformed metal items to allow sliding it over the 'knife shaft' possibly, with a collar of some sort with a set screw or two, to hold the dish edge against the 'wall' where the bearing is housed. Maybe the dish could remain pressed against the bearing's 'wall' and just the collar could turn with the knife's shaft?
It's a 'rough' idea of how to possibly seal the bearing from grass access, which should remedy the issue.

Hi Coyote Machine, thanks for the input and the advice. I neglected to mention that I did in fact drain the gearbox fluid and replaced it with synthetic 80-90 weight on a guess? I can redo it if that is incorrect. There is a top plug and the bottom drain plug. There are also two small plugs to check the level, I am used to only one on most equipment. I did fill it to the level of the second, highest most check plug.

I see the plugs referred to as vented in the manual, but I don't see how they are vented? The top one seems like solid metal to me??

Thank you for the compliments on the pics. I still use a Windows phone and it's a bit old and uncooperative at times lol.

Hmmm, thanks for the suggestion about using a "dish" of sorts and attaching to the mower wall. I had not thought of that, I was thinking of attaching something directly to the collar. Attaching it to the wall may eliminate the heat sink concerns that Leon is having. Thanks for the idea, any and all thoughts are welcome. I am going to go take a look at the mower in a few minutes and see if I can think of a way to implement your idea. I'd really like to be able to successfully mow with this machine, I have fallen in love with it even on such a short test mowing.

Thanks again!

 

[goatchay]

Sorry if I made a mess of this thread and made it hard to follow. I will be sure to reply with quote in the future.
Chris

 

[KWentling]

206 (6206) is a common bearing. The C2 is the internal clearance designation. C3 is the most common clearance that you see. A C2 has less internal clearance so it would commonly not be a tight fit on either the shaft nor the housing. I don't know why they would use a C2 in that application. Most of the bearings that a bearing house will have will either be sealed or shielded on both sides. You can take a pick or small screw driver and pop one of them out. You would probably want a shielded one in this case. It would be a good idea to try and shield that bearing somehow.

 

[Coyote machine]

Hi Coyote Machine, thanks for the input and the advice. I neglected to mention that I did in fact drain the gearbox fluid and replaced it with synthetic 80-90 weight on a guess? I can redo it if that is incorrect. There is a top plug and the bottom drain plug. There are also two small plugs to check the level, I am used to only one on most equipment. I did fill it to the level of the second, highest most check plug.

I see the plugs referred to as vented in the manual, but I don't see how they are vented? The top one seems like solid metal to me??

Thank you for the compliments on the pics. I still use a Windows phone and it's a bit old and uncooperative at times lol.

Hmmm, thanks for the suggestion about using a "dish" of sorts and attaching to the mower wall. I had not thought of that, I was thinking of attaching something directly to the collar. Attaching it to the wall may eliminate the heat sink concerns that Leon is having. Thanks for the idea, any and all thoughts are welcome. I am going to go take a look at the mower in a few minutes and see if I can think of a way to implement your idea. I'd really like to be able to successfully mow with this machine, I have fallen in love with it even on such a short test mowing.

Thanks again!

You're welcome. On the vent plug question I would surmise the top plug may be the vent plug. It might have been a replacement for an actual vent plug which got lost and then replaced with a standard plug. Most bearings and gear sets need to be bathed in gear oil, and there must be room for expansion and venting so pressure inside the gearbox can be relieved or seals will blow out and gearbox will run dry with bad outcomes.
Again I don't know anything about your particular mower specifically, so checking with those who do may be able to clear up which oil/gear lube to use and to what plug level to fill the box. How high on the box is the top plug to which you filled to?

To the bearing shroud, (seal) you're looking to devise, another possibility is a metal small size dog water dish which might have a flange at the outer edge. I mention this because it might be able to use the flange to seal the dish to the bearing wall with an epoxy or high strength, heat resistant silicone.
Then a split collar, if there is room, to keep the grasses/debris from entering the hole where the shaft passes through the dish. my thought is by removing direct access for the grass it would have a hard time getting past the dish area, and if the dish has enough room to its smallest diameter, where the split collar would attach the grass would not have the energy to pass by the collar and find its way through to the bearing without loosing momentum, and thus have no energy left to pass to or through the bearing. I'll have to view the pics again to determine the room for the dish and split collar.
Like this:https://www.homedepot.com/p/Climax-...gclsrc=aw.ds&dclid=COODvMuT-NwCFQaiewod5ckGnQ

 

[goatchay]

You're welcome. On the vent plug question I would surmise the top plug may be the vent plug. It might have been a replacement for an actual vent plug which got lost and then replaced with a standard plug. Most bearings and gear sets need to be bathed in gear oil, and there must be room for expansion and venting so pressure inside the gearbox can be relieved or seals will blow out and gearbox will run dry with bad outcomes.
Again I don't know anything about your particular mower specifically, so checking with those who do may be able to clear up which oil/gear lube to use and to what plug level to fill the box. How high on the box is the top plug to which you filled to?

To the bearing shroud, (seal) you're looking to devise, another possibility is a metal small size dog water dish which might have a flange at the outer edge. I mention this because it might be able to use the flange to seal the dish to the bearing wall with an epoxy or high strength, heat resistant silicone.
Then a split collar, if there is room, to keep the grasses/debris from entering the hole where the shaft passes through the dish. my thought is by removing direct access for the grass it would have a hard time getting past the dish area, and if the dish has enough room to its smallest diameter, where the split collar would attach the grass would not have the energy to pass by the collar and find its way through to the bearing without loosing momentum, and thus have no energy left to pass to or through the bearing. I'll have to view the pics again to determine the room for the dish and split collar.
Like this:https://www.homedepot.com/p/Climax-...gclsrc=aw.ds&dclid=COODvMuT-NwCFQaiewod5ckGnQ

Well, I thought that I had posted this yesterday but either I forgot to hit Send or it timed out or something. Sorry about that.
Hi Coyote Machine, (I actually saw a coyote outside my window last week, there are plenty of them around here!)

I will take a closer look at the top plug/vent plug. I think that the top plug and the bottom drain plug were identical though, I don't recall it being vented. I don't know if I have ever seen a vented steel plug, only plastic etc. So I'm not sure what to be looking for.

I will take some pics of the smaller inspection/level plugs. Off the top of my head, I would say that the lower one was at about the midway/halfway point of the gearbox, with the higher one, that I filled to, maybe about 2/3 of the way to the top of the gearbox. I only ran it for probably less than 5 minutes before the belt smoked due to the grass wrap.

That seems like a great idea regarding the water dish and split collar. The only thing is that I have such little clearance to work with that it would have to be cut down more to a "saucer" size rather than bowl size. I had not thought of a split collar. Actually, I think that if I could just add a split collar extremely close to the collar of the bearing housing, assuming that the collar had an OD quite a bit bigger than the OD of the bearing collar, that that alone may help the problem.

The issue again comes down to clearance. I don't know if that is enough shaft to clamp a collar on to. The factory weights and even the outermost knife station are very close to the edge of the rotor shaft. I think the knife station's weld actually bevels off to the end of the shaft. It may be visible in the pics. i will have to look more closely. But I think that your idea is something that would generally work to solve the problem if I am able to implement something along those lines.

Thanks again and have a great Sunday!

 

[jthibodeau89]

Based on your pics, it appears that you could attach a piece of bar stock to the end counterweights. Since you plan to use the heavier flails, a little more offset weight on the end might not be a bad thing.

As the grass wraps around the end of thr rotor, the pressure pushes it sideways through the OD gap of the seal washer. The piece of barstock on the rotor prevents the grass from wrapping into the gap at the end of the rotor.

The bearings in your pics are shielded. I don't think that seals will survive in this application.

Thanks for your well wishes. Got all 4 hydraulic cyls pulled from the Agco and delivered to a local repair shop. Estimate is $80-$100 per cylinder to rebuild. Hope to have it back in operation in 10 days.

 

[goatchay]

Based on your pics, it appears that you could attach a piece of bar stock to the end counterweights. Since you plan to use the heavier flails, a little more offset weight on the end might not be a bad thing.

As the grass wraps around the end of thr rotor, the pressure pushes it sideways through the OD gap of the seal washer. The piece of barstock on the rotor prevents the grass from wrapping into the gap at the end of the rotor.

The bearings in your pics are shielded. I don't think that seals will survive in this application.

Thanks for your well wishes. Got all 4 hydraulic cyls pulled from the Agco and delivered to a local repair shop. Estimate is $80-$100 per cylinder to rebuild. Hope to have it back in operation in 10 days.

Hi Thibodeau,

I'm glad to hear that you're making progress on your tractor. That financial damage on the bill for the rebuilds seems reasonable, hopefully you will be up and running again soon.

I am leaning towards a solution along the lines of what you suggest, I just don't think I have the clearances to do much else. I just don't want to make the rotor unbalanced and create other problems because it ran extremely smooth.

It rained all day here. I have not had a chance to purchase the new bearings yet, hopefully tomorrow. I was going to replace the outboard bearing on the extension shaft at the upper pulley, but I did not realize it was a flange bearing mounted in a housing and sold as one unit. It's not cheap from what I can tell. I have seen bearing inserts for this bearing which are cheaper, but I don't know how hard that is to do or press in compared to a regular bearing. I have not pulled the bearing housing off yet to inspect the bearing to see if it's worn, it may be ok. I was just going to change it because I figured it was probably the same 206kl bearing as on the shaft.

It is instead a Sealmaster S-A SK509

Also, I'll attach a pic of the gearbox to show the second highest plug that I filled the level to. As well as a pic of the spring situation. Originally, the long spring was attached to the triangular brace/bracket, it was just hooked on towards the bottom. You may be able to see a notch that it made over the years on the piece of flat stock that make the triangle. The spring did not seem to provide enough force.

I added a second one, hooking it to the long bolt going through the flange bearing. All three other bolts are shorter, this on is longer and I thought maybe it was intentionally designed that way in order to hook the spring to the bolt, although I realize that is probably unlikely. But I don't see any other points to hook the spring? It seemed to be doing fine with this set up until the grass wrap/belt smoke.

Thanks again for all of the help.

 

[jthibodeau89]

The sk509 is easily removed from the housing. The outside of the race is ground with a spherical radius. Once the shaft is removed, use a punch to drive on the outer race 90° from the notch in three housing. The bearing will roll in the housing, and will lift out from the housing at the clearance notches. The bearings on both of my JD flails attach the same way. Hard to understand at first, but once experienced it is simple. It also makes the bearing self- aligning.

 

[jthibodeau89]

Forgot to mention you will probably need to remove the housing from the mower frame to give the bearing room to tilt on the back side. In your pic, you would place the punch at the 4 o'clock position and drive the race inward into the housing. The bearing will flip in the housing due the the spherical radius on the outside of the race. The the bearing will lift out at the clearance notches. No reason to replace the housing unless it is cracked.

 

[goatchay]

Forgot to mention you will probably need to remove the housing from the mower frame to give the bearing room to tilt on the back side. In your pic, you would place the punch at the 4 o'clock position and drive the race inward into the housing. The bearing will flip in the housing due the the spherical radius on the outside of the race. The the bearing will lift out at the clearance notches. No reason to replace the housing unless it is cracked.

Great info Thibodeau! Thank you! I have never changed the bearing insert on a flanged baearing and had no idea how that worked. Thanks for the explanation, that clears things up a lot.

I stopped by the bearing supply to get the new bearing today. The sk509 number of the flange bearing apparently didn't cross with anything that they had or had heard of. I still need to remove mine and check it, I was just going to change it if the price was reasonable for the insert. He said that they would just need the shaft diameter to match it up.

They did have the Fafnir 206KL bearings. They close at 4:30 and were actually locked up when I got there but were able to let me in. As a result of being in a rush, I forgot to ask them if they had a sealed version as Leon suggested. I just handed them my old bearing and they gave me two new 206KL bearings. I will call them tmw about the sealed version because I will probably not have time to put these on tonight anyway.

But when I left, I noticed that there is a difference in the bearings. It is slight, but it's in an area that is critical to the grass wrap issue. I will include some pics. The inner race of the new ones protruded slightly more than on the old ones. Which would in turn push the seal washer and cutter shaft that much further away from the bearing housing collar and open up the gap around the seal washer and the bearing housing collar, making it easier for grass to get inside.

I wish I had looked closer at the original bearings before I pressed them out of the housing. Is it possible that the original race protrudes less because of beating it out of the housing with a hammer? I didn't have to whack it hard or anything, 3-4 taps for each bearing.

Also, the box for this bearing say Timken 206KL, but the nomenclature on the bearing is a little different. The bearing has :

206-L WR Z17 SFA then another spot says Z17-AF TURKEY

The back of the inner race says 206KLZ17P

I realize that the Z indicates one side shielded, but wasn't sure about the rest. And it doesn't mention the C2 tolerances etc. I think I read that post wrong and/or misunderstood it anyway. I thought that the higher the number..C2 C3 etc, the tigher the clearances. But apparently the lower the number, the tighter the clearances. So a C2 is tighter clearances apparently and a C3 is looser. Possibly Mott wanted tighter clearances due to the balancing/vibration of the shaft?

Regardless, I don't know what the new one is rated at, or if it matters??

I will ask them tmw if they have a sealed version of this and also get the shaft diameter for the flange bearing.

This may be a stupid question, but....When I get it all put back together with the new knives and bearings and belt, what would happen if I tried to mow with the mower raised up off of the ground with the 3 point, with the mower in mid air? And them made lower passes over and over?

Leon, I have read other post that you mention the vacuum that needs to be created by the mower, so this may be a bad idea or not work at all. Just trying to reduce the chance of the grass wrap for this initial first mow.

Thanks again to everyone.