B21 Clutch Problem?

[100 td]

A couple of things to consider.
I personally would replace the rear main engine oil seal while you have it apart and any welsh plugs on the rear of the engine if it has any?
One other thing I would do if I had it in that state, drain tranny and axle housings, remove HST tank bottom cover and clean out sludge.

 

[brain55]

Can't quite see but looks like pilot bearing is toast? I'm wondering if it's the chicken or the egg, does the clutch spline slowly wear and then start to run out of centre and flog the pilot bearing, or does the pilot fail allowing the opposite to happen.
Given that this is a HST machine and the clutch is used rarely, meaning it's generally always engaged, I'd take a guess at the centre splines start to wear, and then each time the clutch is engaged it clamps a tiny bit out of centre causing out of balance and more wear and ultimate failure. I wonder if I can get a borescope in through the inspection hole and into the centre of mine for a look?
Looks like the throwout bearing carrier has touched the pressure plate fingers, should be able to take the burrs off the end and reuse.

The pilot bearing actually looks good to me. It's still intact and the yellow teflon like material looks good. I have seen B-series where the bushing was gone and the crankshaft was worn to where it had to be machined for a sleeve for the bushing to fit into. Your splines failed from shock loading not from shaft misalignment in my opinion.

 

[100 td]

Can't quite see but looks like pilot bearing is toast?

The pilot bearing actually looks good to me. It's still intact and the yellow teflon like material looks good.

OK, thought is was a bearing, not a bush, as I said, can't quite see.
What's the teflon in front of the bush for, or is it the bush lining?

 

[TomSeller]

The pilot bearing actually looks good to me. It's still intact and the yellow teflon like material looks good. I have seen B-series where the bushing was gone and the crankshaft was worn to where it had to be machined for a sleeve for the bushing to fit into. Your splines failed from shock loading not from shaft misalignment in my opinion.

You sure were right on the mark when you predicted the splines were gone. By shock loading do you mean quick forward/reverse movements as when repetitive FEL loading?

 

[RobbieBones]

OK, thought is was a bearing, not a bush, as I said, can't quite see.
What's the teflon in front of the bush for, or is it the bush lining?

At first I thought the pilot bushing looked bad but as you say the Teflon is on it. If I needed one where do you buy one? I haven稚 seen any on all the clutch diagrams I looked at.

 

[RobbieBones]

The pilot bearing actually looks good to me. It's still intact and the yellow teflon like material looks good. I have seen B-series where the bushing was gone and the crankshaft was worn to where it had to be machined for a sleeve for the bushing to fit into. Your splines failed from shock loading not from shaft misalignment in my opinion.

OK, thought is was a bearing, not a bush, as I said, can't quite see.
What's the teflon in front of the bush for, or is it the bush lining?

At first I thought the pilot bushing looked bad but as you say the Teflon is on it. If I needed one where do you buy one? I haven’t seen any on all the clutch diagrams I looked at.

 

[RobbieBones]

Standard clutch 'job' parts (Clutch plate, Pressure plate, Release bearing, Pilot bearing) and the splines on the trans input shaft look pretty beaten up - so you better think about replacing/repairing that. Maybe look at the input shaft bearing as well...
How's the flywheel facing?

Well done getting this far.

Flywheel looks great. The throw out bearing does have slight play when you rock it side to side but the trans shaft does not move.

 

[brain55]

At first I thought the pilot bushing looked bad but as you say the Teflon is on it. If I needed one where do you buy one? I haven’t seen any on all the clutch diagrams I looked at.

It's on the page with the crankshaft. The bushing and the seal both.

Most of the shock loading happens getting on and off the pedal quickly.

 

[RobbieBones]

The pilot bearing actually looks good to me. It's still intact and the yellow teflon like material looks good. I have seen B-series where the bushing was gone and the crankshaft was worn to where it had to be machined for a sleeve for the bushing to fit into. Your splines failed from shock loading not from shaft misalignment in my opinion.

Could the splines fail because the clutch pedal wasn’t adjusted right or needed adjustment periodically? The throw out bearing isn’t pressed into the fingers far enough to fully disengage?.????

 

[brain55]

Could the splines fail because the clutch pedal wasn’t adjusted right or needed adjustment periodically? The throw out bearing isn’t pressed into the fingers far enough to fully disengage?.????

Not likely. The clutch if partially disengaged would slip, absorbing the load that way.

 

[TomSeller]

Assuming the spline design is common to the Bs in general. I can see why a B21, which is a lot of tractor mass for the frame size, would stress the splines in rapid pedal operation. I subscribe to the "easy does it" pedal motion and since mine is used, I don't know what the spline condition is. No evidence of any issues, just not a repair I would look forward to.

 

[RobbieBones]

Not likely. The clutch if partially disengaged would slip, absorbing the load that way.

Got it. Thanks for your help. I’ll buy pilot bearing/ bushing just to compare what a new one looks like. As for The clutch shaft. There is a slight grove in it about 3/4 inch from the tip but looking at diagrams it looks like It’s suppose to be there. No play at all clutch shaft. I think the bearing for it is tight. But my concern is how beveled backwards the splines are. Is that normal?

 

[brain55]

Got it. Thanks for your help. I値l buy pilot bearing/ bushing just to compare what a new one looks like. As for The clutch shaft. There is a slight grove in it about 3/4 inch from the tip but looking at diagrams it looks like it痴 suppose to be there. No play at all si I think the bearing for it is tight. But my concern is how beveled backwards the splines are. Is that normal?

The shaft needs to be replaced, the splines should be perfectly straight, they are quite worn.

 

[RobbieBones]

Is there a way to test the transmission? Meaning turning the clutch shaft etc to see if there is anything broken inside that may stop gears from turning or break them etc?

 

[brain55]

Is there a way to test the transmission? Meaning turning the clutch shaft etc to see if there is anything broken inside that may stop gears from turning or break them etc?

Not really, but you can remove the 3-pt cover and the other cover over the main transmission and visually inspect the gears. The HST can be disassembled too, but I'd leave it alone, they're usually pretty durable.

 

[RobbieBones]

The shaft needs to be replaced, the splines should be perfectly straight, they are quite worn.

Yeah your probably right. Have to make sure it’s just not the picture. Thanks again for all your knowledge.

 

[RobbieBones]

I was off on the machines hours it has 1470hrs.

 

[RobbieBones]

Just a quick update. Clutch shaft, throughout bearing and spring all replaced. New bushing in flywheel, pressure plate and friction plate installed. Included a better picture of the damaged old clutch shaft.

 

[RobbieBones]

Few questions.

Kubota doesn’t recommend loctite on any bolts I touched so far. Anybody use it?

What if any lubrication of the clutch rod and throughout bearing is needed?

Is kubota paint any better then krylon or Rust-Oleum?

 

[dfkrug]

Kubota doesn稚 recommend loctite on any bolts I touched so
far. Anybody use it?

What if any lubrication of the clutch rod and throughout bearing is needed?

Is kubota paint any better then krylon or Rust-Oleum?

I don't use Locktite on these bolts. Properly lubricated and torqued, yes.

I also use MoS2 grease on the TO bearing and splines, plus the pilot bearing. They do not generally
need re-lubing.

I have used OEM Kubota orange (old orange and new orange), but anything close
in color will do, IMO, like Rustoleum. Your older paint is faded somewhat anyway.

If you have not assembled everything yet, it is easy to open up the charge pump and
see if it is worn. Mine was, so I replaced it. Wear is due to dirty oil.