Clutch Repair Kama 554

[3RRL]

Dec 22, 2008 17:56:04 GMT -5 stumppuller said:

Rob, I can sympathize with you being gun shy about TOB's, but I suspect that your particular failure was a fluke. The only TOB failures I ever had was with a car using a graphite bearing. (the English did a lot of strange things to save a penny here & there; even my motorcycles had a single ball to push the plates apart)

TOB's have a very low duty cycle in the overall picture of things and not an extremely demanding one at that (low speed, low precision). I'm guessing that it came from the factory with inadequate grease or construction. A TOB should last at least as long as the clutch in normal use. In your shoes, I would make sure there was sufficient grease in the replacement bearing , install it and forget about it. If you need reassurance, look up the loading charts for that bearing spec; make some estimates for duty cycle, loading and speed and you will get a result in longevity for those parameters.

Hi Bruce, Merry Christmas today!
Yes your are right, I'm a little paranoid about the throw out bearing seizing up again.
I'm thinking of installing this new high quality Japanese bearing instead of the one Chip is sending out, but like I said before, I'll wait until I inspect it. I'm hoping what you said is true, it just being a fluke and not to worry about it. On the other hand, while I have the thing apart I might as well add a safety feature inside there. The sealed bearing has a little clearance between the race and the bearing cover. I'm thinking if I can get some grease to sit on that gap it will migrate to the ball bearings as it gets "sucked" in a little at a time.

My thinking stems from all other bearings that have greaseable nipples. Sealed or not, being able to supply a fresh lube to it has to be better than not. There has to be some significant benefit, even if little or even just for peace of mind . It will be easy to do for me so I'll just go ahead and do it anyway. I plan to test the lubricating scenario to see how much I can pump in there and what that does ... where does the grease go, how much, etc. If it flows like I plan (follows the path), then a squirt or two should keep it lubed adequately. I could grease it 3 or 4 times a year. I'd feel better about that.

Worst case scenario is I get too much grease in there and have to change the clutch. For some reason, I like thought of doing that better than having the agonizing paranoia thinking my TOB might freeze up and having additional parts get destroyed. If it works and I get longevity out of it, I'll never really know whether it was due to the ability to keep it lubed or just a better throw out bearing? Of course, either way it would require another tractor split, but at least I'll know what I did was not a detriment.
I'm betting on that my little experiment will be an improvement
Rob-

[bracabric]

Rob, you are a brave,brave man and ingenious.you have my TOTAL respect. I look on in awe,
Dick

[captinjack]

The old saying that "if some is good........more is better" isn't always true.

I remember starting up a large industrial fan that had two large pillow block bearings. The plant personnel geased these bearings while all the "brass" watched. After running for the fan for the first time, I took bearing temps and found them to be really hot and worse yet, the temps were rising. We finally had to turn off the fan as we all knew that the bearing were going to fail.

What was wrong? I read the literature supplied with the fan and sure enough, under the troublshooting section "Bearings overheating" it said that the bearing were already greased at the factory and that too much grease would cause them to overheat and fail!

That's the first time I had heard of that and that also goes for the other people who watched the guy grease the bearings. Hooodathunk? It was true, as we installed new bearings and the overheating went away.

[3RRL]

Hi Dick, thanks for the compliments!
I don't know about being brave or ingenious, but I know I have to get that old Kama running again no matter what. So I guess one must do what is necessary at times.

Hi Jack,
Yes, I agree with you that too much is not good either.
Pillow blocks normally have a grease fitting on them which (to me) would mean you can add either grease or oil so your guys were not off the mark. Your plant personnel must have over greased the heck out of them (or used too heavy a grease) for the bearing to heat up like that. Perhaps a couple shots would've been ok? My milling machines have one grease fitting and several oiling cups for way lube and spindle oil that lubricate the higher rpm bearings. But instructions, of course, are invaluable.
Rob-

[3RRL]

Update on my clutch project.
After the Christmas family gathering, we made it back up to Three Rivers. My oldest son (Aaron) and his family came up to spend several days with us. Aaron helped me get all the plywood and backing screwed onto the shop walls. They go behind all the machinery to keep metal chips from burning the fiberglass insulation on the walls. It took us a full day because we had to remove all the electrical conduit first and then re hang it all. Then Sunday we relaxed and watched some football games. Ken (quikduk) and his family vacationed at the motor home park nearby so they visited that day too. His kids and my grandkids had a blast playing all around the property.

After all the visiting, this morning I got back to clutch work.
I got Chips parts and compared the throw out bearings. The OEM bearing is on the left, the Napa bearing in the middle, and Chips replacement bearing on the right. A couple of things I noticed about the replacement bearing. First, the bearing race where it presses onto the TOB seat is very narrow compared to the OEM and Napa bearing. The shield was sort of loose fitting and what bothered me the most was that the race could shift inside the seal about .050" or so. In other words, the race was not held concentric to the shield nor the face, which meant the ball bearings inside were not contained on the race. You could also feel the ball bearings roll inside. Perhaps it doesn't mean anything if the front face rotates, but that bothered me?



The Napa bearing was solid and you can not feel the slightest bit of movement. You couldn't feel the ball bearings at all as I rotated it ... it was smooth as silk. The difference in quality was evident, but it was also more expensive than the replacement bearing.
I decided to use the Napa bearing instead of the replacement bearing.
Rob-

[3RRL]

You saw the grease fitting I installed on the TOB Seat.
My next goal was to have a couple places where grease could find it's way to the small .020" radial gap between the bearing race and shield. I set the mill head on 15 degrees and picked a point on the TOB Seat where the bearing race hits that ledge. I drilled 3 holes on the top side only. The holes found their way into the grease cavity inside the Seat as you can see in these photos.



With the TOB pressed onto the Seat, part of the holes are exposed to the outer edge of the bearing race and also right to the small gap between the race and shield. If you look closely in second photo, there are 3 small "nicks" which are the holes in that ledge. They barely break through to the OD of the Seat itself. But if you look inside the Seat, you can see the light coming in there. I shined a flashlight onto the race and shield so you could see the holes from inside the Seat.



I figure if I can get a small amount of grease to that gap, as the bearing turns it will "leach" grease into it and the grease will eventually migrate onto the ball bearings. It's a way to keep the Seat and bearing lubed.
As long as I don't over grease it, it should work great.

[3RRL]

To make sure that it was all going to work as I planned, I had to assemble the Seat and grease fittings onto the Support Tube inside the bell housing. Instead of the knot, I tightened the grease hose into a better position without the knot. With both ends fastened, it should stay that way.

I hand packed the grease groove best I could and slid the Seat onto the Support Tube. Then, after attaching the spring, I slid it back and forth and wiped any excess grease off. This was so I could visually inspect where the grease was going. I was hoping I could "feel" when the grease cavity was full and after that, see how many pumps it takes to get some grease out those holes. I also wanted to confirm the grease would go out those holes before finding it's way out of the slight clearance between the sliding Seat and Support Tube.



The result was great.
I got a small grease gun that I will only use to lube the TOB. I could "feel" when the cavity got filled up because there was more resistance to the grease gun. I checked with a mirror at this point and no grease had come out the holes nor between the sliding Seat and Support Tube. Then I pumped 2 more times and saw grease starting to come out of the 3 holes right by the race and shield. The last photo has a small mirror which shows the back of the TOB and you can see the small gobs of grease just starting to come out. You can also see no grease has come out between the sliding Seat and Support Tube.

With the Zerk fitting easily accessible from the outside, I'll check it in one month ... add only if I can feel it go easily. If none is needed, I'll check it again the following month and so on until it needs more lube.
Maybe it'll never need any more lube, but if it does, I'll know it.
Rob-

[Rich Waugh]

Damned ingenious and excellent work as usual, Rob. In a couple more years that tractor will be indestructible if you keep on with this sort of thing. :-)

Rich

[GuglioLS]

Hey Rob,

As usual nice machine work customizing the bearing carrier with those 15* grease channel holes. Perhaps consider placing an O-ring around the back of the bearing and over the holes? Maybe that would help force grease into that .02 gap into the bearing race and slow / reduce the likelihood of grease slinging out? Maybe worth a try?

From what you describe the replacement bearing is rather sloppy (bearings too small for a tight fit. All the grease in the world will not take up the gap. So I can fully understand why you would not take a chance using that one. The NAPA bearing seems to be the ticket.

I sure do look forward to seeing your two tractor halves going back together. Seems like your almost ready for that, right?

Larry

[FlyHiFlyLo]

Oh rob that is retarded.

;D

[3RRL]

Thanks Rich, Larry and you too Scott (lol)
We think alike Larry. I thought a lot about the "O" ring right there and decided to add an "O" ring groove ... a small one to keep it against the bearing. But in my haste to take these photos to show how the grease migrates and approaches the .020" gap, I forgot to add it.
Dang, now I have to remove it all and press that bearing off again.
Plus I get to deal with all that black graphite impregnated grease.
Thanks for reminding me.
Rob-

[3RRL]

I've got to turn up the clutch alignment tool this morning but first have to get my lathe set up.
*Yeah more set up work. I was waiting to finish up putting the plywood behind the lathe walls. Then I'll assemble the clutch pack on the bench like Greg suggested in his earlier posts.
I guess after that it's time to get the tractor together?
Rob-

[Rich Waugh]

Don't rush into putting the beast back together, Rob. If it weren't for you and your adventures with breaking tractors, there'd be nothing new to read here. (grin)

I wasn't going to say anything about that O-ring but, since you brought it up, wouldn't that be a good application for a quad ring? Overkill though, maybe.

Now is also the time to add quick-disconnects on all the hydraulics and electrics so the next time you have to split the tractor it only takes an hour. :-)

Rich

[3RRL]

Don't worry about not having anything to read about Rich.
I'm sure I'm good for a couple hundred more breakdowns and F/Ups before I kick off. ;D
For example:
I got my lathe all set up and ran power to it. I started it up several times and ran the feeds back and forth lubing it all up. Then I chucked up the piece of aluminum I got to make the clutch alignment tool and was gonna cut it. I have to run a 10hp rotary 3 phase converter motor and the lathe is a 7-1/2hp motor so that's a lot of power consumption. What I didn't know was Loretta was doing a load of laundry and drying another in the electric dryer. I blew a fuse in the solar panel. Then I found out my solar guy has NOT wired up the generator by pass to the shop. So I couldn't cut anything today.

Now I have a couple questions.
Perhaps Chip or Tommy or Ronald can help with this or any of you guys who know. I want to set up the clutch on the bench like Tommy and Greg referred to.
First, there is a 105mm stack height called out in the manual. It is the dimension from the flywheel face to the top of the release fingers.
-How critical is that dimension?
The reason I ask is that I have to move my throw out bearing forward quite a bit, about .230" (5.8mm) from where it sits now. I can do that by adjusting the outside linkage. That puts the throw out bearing towards the end of the Support Tube(which it slides on) and part of the Sliding Seat leaves the Support Tube. It also would make the throw out bearing more "inside" the clutch pack. If I use the place where the throw out bearing sits now, with the outside linkage as is, I would have to make the stack height about 5.8mm taller than the 105mm called out in the book or 110.8mm stack.
Is this acceptable?
Or should I hold the 105mm as called out in the book? I know I can do that by adjusting the outside linkage, right?
But my question is which is better to do or does it really matter?

Second is how do you set the stack height on the bench.
My clutch pack has a gap in it where the Belleville type disc springs keep it open.
-Do I leave it relaxed and then set the stack height?
-Or do I compress the clutch pack together like it would be when bolted to the flywheel?
See these photos. First one is relaxed and second one has it clamped up. I suspended the clutch pack on 1-2-3 blocks from where the flange would seat against the flywheel.



Once I get the right way to do this, I will set each finger height by using gage blocks and a drop indicator to the high point on each finger. They should all come out within a thousands (.001" or .025mm) of each other this way.



If the clutch pack needs to be compressed like it would be when bolted to the flywheel, and if the stack height can vary from the 105mm book dimension, it is ready to bolt back onto the flywheel now. I set the 1.2mm PTO clutch gap and also took into account the 2mm gap between release fingers and throw out bearing (where it sits now).
Let me know which way to bench set it.
Thanks,
Rob-

[3RRL]

Good morning,
Yesterday I spoke to Tommy who helped me a lot in understanding how to set the clutch on the bench.
Before bolting the tractor together, I made a felt washer that fit behind the throwout bearing where the shield and Sliding Seat (which holds the TOB) meet. This is instead of the "O" ring idea. It's to keep the grease that comes out of those little holes localized around the .020" shield gap. I was worried about the "O" ring and "felt" this is better alternative (no pun intended). I tried to take a photo of it.
Maybe you can see the little mirror in the photo which shows the brownish colored felt washer?



Also, I have a question about this sensor which is screwed into the bell housing. When the tractor is assembled, it appears to rest over the rotating flywheel. Could it be a speed sensor for my tachometer?
What is it?