Clutch Repair Kama 554

[Rich Waugh]

Rob,

No experience on tractor clutches, but some on other rigs. I do recall one piece of equipment that had a zerk on the TOB carrier, though it was called something different because it was stationary equipment. Same working principle, though. For what it's worth I'll offer this:

You can add the zerk fitting and grease passage now for very little effort and almost no expense. The groove is already there, so you drill and tap a hole and screw in a 75 cent zerk fitting. If you never use it, you're out a half hour and seventy-five cents. But if you do need it, it will be absolutely priceless, versus splitting the tractor again.

I would imagine you're planning to reassemble the carrier with a bit of grease in the groove, since there is evidence that it was done that way at the factory, right? So why not make it easier to maintain that grease in the future? Likewise for the TOB. Some seem to come with a grease hole and some don't, according to Chip. If the new one comes without a hole, I might be tempted to put one in it with a carbide burr, given that you already know the result of a frozen TOB. As long as you get the bearing clean after the hole-mking process, it should be a no-loss situation.

Of course, the NAPA unit might very well be a sealed, pre-lubed bearing, nullifying that issue. I believe that NAPA bearing is for a Nissan and probably a sealed unit.

There you have my uninformed opinion. :-)

Rich

[bradblazer]

FWIW I looked up the clutch replacement procedure in the Haynes manual for my Explorer. Here are the relevant quotes under "Clutch release bearing - removal, inspection and installation"
"4. Apply a light coat of high temperature lithium grease to the face of the release bearing where it contacts the pressure plate diaphragm fingers.
5. Lubricate the inner bore of the bearing and bearing carrier with a synthetic long-life grease. Don't use petroleum-based grease."

[3RRL]

Regarding the sliding seat, in the plastic injection mold making trade there were medical molds (and others) that couldn't have any contamination from lubrication. We used to buy Graphalloy Graphite Impregnated stock and turn up our own bushings if they did not supply sizes for our custom applications.
We also used Graphite Plugged Bronze Bushings such as these for similar reasons.
The bronze was used for mostly low pressure though. I suppose I could turn the ID of the Seat and press one in, but I'd rather install a no brainer Zerk fitting.

That's why I asked the lube/no lube question.
The intent is to prolong the life of the part (parts for some) that failed and perhaps avoid (another) tractor split. As you can see from my documentation, the clutch itself and other components could last for thousands of hours had the throw out bearing not frozen causing damage and consequently, a failure.

LOL ... I'm just trying to make them work better without making it worse. Maybe I'm over thinking this, but having seen it with my own eyes causes me concern. What I'm getting at is I don't want to be splitting the tractor every 500 or 1000 hours to change the throw out bearing, especially if the other components are still good.
I can understand having to change the clutch when it wears out, of course.

Another factor to consider is that when I spoke to Chip, he told me they don't get many Kama's in for service with 500 or 1000 hours because no one has logged that many hours on them yet. He said they've gotten some with 200 and 300 hours. (Correct me if I'm wrong please Chip). With that in mind, perhaps there might be (common) failures looming ahead for others when approaching those hours ... problems that we're not aware of yet because lack of a track record (history) with these machines at the higher hours like mine? You can see from Greg's post and photos, his problem was of similar nature.
Anyway, something to think about, right?
Rob-

[psj12]

I have worked on heavy equipment and they almost always have a grease fitting on the TOB sliding carrier. Use grease sparingly.

[3RRL]

I have some time before my parts from Chip arrive.
I decided to buy that Napa TOB their pnN3078. There are a couple of differences in OD and thickness.
The main thing is that the ID on both will give me a good press fit onto the TOB sliding Seat.



I measured thickness, OD and ID.
Here's what I found.
Sliding Seat dimension where TOB presses on is 2.560"

Bearing Dimensions
OEM ID 2.5583"
Napa ID 2.559"

OEM Thickness .805"
Napa Thickness .8683"
I should be able to take up the .063" difference when setting the finger clearance, right?

OEM OD 4.093" Effective working surface 3.840"
Napa OD 4.019" Effective working surface 3.710"

I will wait until I get Chip's replacement TOB to decide which one I'll install. However, I should be able to use the Napa bearing as a cross-over. The Napa TOB is Japanese made for a Nissan or Toyota (I think). There's a picture of the box it came in and it says it's a BCA Federal Mogul Bearing. It's fully sealed and came packed with grease.
Just thought I'd add that information to this thread for those interested.
Rob-

[3RRL]

I also investigated that existing grease nipple that goes to a bearing behind the Seat Support. I found out the Support is bolted to a wall in the rear of the bell housing, which is not the middle box wall. There's no gear oil behind it. That bearing it lubes is like a support bearing between the Support and the middle box. I tried to take a couple photos to show there is a cavity behind the Support wall. The second photo shows the actual middle box behind where the Support is bolted.
So keep greasing that one, it is NOT redundant after all.
Rob-

[3RRL]

After thinking about it for along time, and considering the input from many, I decided to add a grease fitting to the sliding Seat after all. I bought a grease gun hose at Napa and determined the best place for it to attach to the sliding Seat. Then I drilled and tapped the Seat. I also tried to find the best place in the bell housing for the other end. It will stick out with a grease fitting on it, bolted to the bell housing.

It was important to me to place it so there was no or very little force trying to twist the Seat out of position.
I put a loop in the hose which allows the hose to remain in that position like that, sort of static, but when the seat is pushed forward, it wants to retract the seat just like the retracting spring does. The travel of the Seat is about one inch or so, and I checked this loop out for two inches of travel. It should work.

The hole in the bell housing is just above the hole to grease that other zerk in there. Except I don't have to try to fit the tip over the nipple in the dark. It's exposed to the outside.
Rob-

[3RRL]

OK, last thing I did was take some measurements.
I depth mic'd from the bell housing to where the TOB will sit. I used a long parallel and mic'd to a gage block. Then I did the same thing from the face of the flywheel, where the clutch pack is bolted, to the flange of where the bell housing bolts. I got an average because the dimension varied on the flywheel about .020". (I thought it would be closer than that) I will use the difference between the two to set the stack height of the fingers. I will include the 1.2mm for the PTO clutch gap and the 2mm for the finger gap. I will also adjust the free play on the clutch pedal when making my final adjustments. If all my dimensions are right, I should be able to install the clutch pack and all my clearances should come in bang on.
Of course I will check them once assembled to be certain.
Rob-

[Artrac]

rob, nice job on the hose to grease the "bearing seat" as it is labeled in the parts book. I retract my eariler thoughts that it may attact brake dust and cause wear. with the hose, you can add a pump or two once in a while which should be fine. It would be hard for the grease to work its way into the clutch itself, some might get slung to the walls of the bellhousing, but it should hurt. The clutch dust is probably not that abrasive anyway and not much will collect in that grease as it too is probably slung to teh outside by centrifical force when the the engine runs and would have a hard time getting to the center. Again, nice work.

[GuglioLS]

Rob,

Nice addition to the TOB holder. I see you posted that the ID of the NAPA bearing is larger than the OEM. Does the NAPA bearing still press fit onto the TOB carrier?

Larry

[3RRL]

Dec 21, 2008 2:36:25 GMT -5 Artrac said:

rob, nice job on the hose to grease the "bearing seat" as it is labeled in the parts book. I retract my eariler thoughts that it may attact brake dust and cause wear. with the hose, you can add a pump or two once in a while which should be fine. It would be hard for the grease to work its way into the clutch itself, some might get slung to the walls of the bellhousing, but it should hurt. The clutch dust is probably not that abrasive anyway and not much will collect in that grease as it too is probably slung to teh outside by centrifical force when the the engine runs and would have a hard time getting to the center. Again, nice work.

Thank you Chip,
Man, I was really sweating putting the grease line to it since I really value your opinion so much.
You are right about the extra grease being slung to walls of the bell housing. Perhaps you saw the inside of my bell housing and what looked like oil on the walls. Well, it was grease ... probably what was inside the OEM bearing. Probably also why the bearing froze? I figured it out when I saw where the bearing sits inside the bell housing. The very front of the clutch pack housing, the steel cover that holds the fingers, had traces of grease on it too. It had to come from that bearing since the radial pattern inside the bell housing matched that position.
Look at these pictures of the clutch when I first split the tractor. You can see the traces of grease.



I really think being able to grease to the sliding Seat will be a lifetime improvement. However, I didn't make it (yet) so that the grease can find it's way to the throw out bearing itself. I'll look at it some more. I figure I could put several holes into the sliding Seat where the bearing race hits the step on the Seat. I could drill several small holes into the bearing shield around the diameter(in a radial pattern. The grease might migrate from there between the shield and back of the bearing race? It would be better than nothing. That location would keep the grease away from the front of the TOB and clutch but still lube the ball bearings inside.

I think being able to grease the TOB itself is the key ingredient to long life.
As long as the excess (if) grease is slung to the bell housing, it should never come in contact with the friction clutch discs themselves. I have seen that same grease pattern in bell housings before when working on cars.
Rob-

[3RRL]

Dec 21, 2008 8:43:10 GMT -5 GuglioLS said:

Rob,

Nice addition to the TOB holder. I see you posted that the ID of the NAPA bearing is larger than the OEM. Does the NAPA bearing still press fit onto the TOB carrier?

Larry

Yes, there is still a .001" press fit there.
That should be good enough to retain the bearing on the seat. All the working force is pushing the bearing back toward the seat so there is no force trying to push it off. It should stay on.
Of course I will check it to be certain I am satisfied. If it slides off by hand I can grind a groove on the Seat to retain the bearing (or Chicago it ... lol punch it)
Rob-

[quikduk]

Sheesh Rob, you HAVE been busy.

Me? I have been trying to hang the "little" 354 under the tree...

Wise Guy!

See you soon. ;D

[3RRL]

Dec 22, 2008 11:11:43 GMT -5 quikduk said:

Sheesh Rob, you HAVE been busy.

Me? I have been trying to hang the "little" 354 under the tree...

Wise Guy!

See you soon. ;D

LOL ... well, you asked for it.
If you decide to come up, be sure to have your jeep or you won't make it up my road. It's supposed to rain maybe snow, so the road will be muddy. You'll also see the Kama split, if that's of interest. I should have the replacement parts from Chip by then, but my sons are coming up to help put plywood on the walls around the machines. I need to get that done while they're there first and then get to re-assembling the tractor.

I also still have to make the clutch alignment tool. Not only that, but I want to customize the sliding Sleeve a little more to get grease to the throwout bearing. I need to figure out the best way to do that using the migrating method. I think it will work. I don't want grease being pumped in there and get on the clutch itself. Being down in Rancho I will miss several working days up there. No big deal though, I'll just do it after.
See ya soon...
Rob-

[stumppuller]

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.