Disengaged clutch (visually saw it move off the flywheel face) tractor still goes

[777funk]

What could this mean? This was before the throwout spring came loose by the way.

 

[777funk]

I think I read stuck pilot bushing somewhere... not sure though. Whatever is sticking, it's small diameter compared to the clutch and that can't be good.

 

[rScotty]

What could this mean? This was before the throwout spring came loose by the way.

Whatta you mean "What could this mean?" At my house we figure anyone who beats on a clutch through an inspection hole knows exactly what it means...

For those who don't, it means that someone is getting one step closer to getting to take an upclose look at the insides of the bellhousing.

Since it still goes, there's only two things it could be:
1. If your toe can lift the clutch pedal (spring is off) to normal height, then I'd guess the pilot bearing is siezed. High torque will eventually break that loose.
2. If the clutch pedal is not able to be lifted to it's normal height then either the throwout bearing is siezed to the shaft - unlikely - or more likely part of the friction plate is either rusted or jammed or both between the pressure plate and the flywheel. That may or may not come loose on its own.

As for the clutch assembly itself, it is the same single plate pressure plate design that has been used on most every car, truck, and tractor for close to 100 years. You'll recognize every part inside there. There's nothing about that clutch that looks or works any differently from one on a manual shift transmission.

BTW, external to the bellhousing down where the clutch foot lever goes through the floorboard there's a little hook designed to hold the clutch disengaged when the tractor is sitting unused for a long time. It's supposed to help keep the clutch plate from sticking, although I don't know that I've ever used that feature myself.
Good luck,
rScotty

 

[777funk]

Thanks and I think you're right! I was actually counting on splitting the machine when I bought it with the following problems:
-No 3 point functionality
-Stuck clutch
-Front 4wd axles leaking

I figured I'd try to free the clutch with a punch and some oil. That worked. However, as mentioned... not so easy.

The pedal does return but it has a beefy (7/8" diameter extension) return spring on the pedal/linkage just like the brakes. So it has no choice but to return. Maybe this was an add on by a previous owner.

 

[California]

BTW, external to the bellhousing down where the clutch foot lever goes through the floorboard there's a little hook designed to hold the clutch disengaged when the tractor is sitting unused for a long time. It's supposed to help keep the clutch plate from sticking, although I don't know that I've ever used that feature myself.
Good luck,
rScotty

I think that lever to hold the clutch pedal down is needed in Japan where the tractor can go from running half-submerged in a rice paddy, to being put away wet and parked until next year's planting season. Its rare to find a stuck clutch on an American car or tractor, but it must be common in Japan for Yanmar to include it.

Photo on the Yanmar-Japan website:

 

[777funk]

When I bought the tractor (with the problem) there were quite a lot of threads about stuck clutches. Not only Yanmar though... all brands. It says in the Yanmar 336D manual that the clutch lock down is to keep it from getting stuck when stored for long periods.

Similar to that Yanmar photo is this old ad from '75 on Deutz. They have it almost up to the snorkel in water!
The reliable Deutz 06 (1975) - Deutsch - YouTube

The German advertising can add a little humor once in a while.

 

[777funk]

Well all has been removed and ready to split. I used cement blocks, 2x4s and shims to hopefully get the front half situated. Just bell housing bolts to go. I removed the steering box and re-latched the loose clutch return spring.

I've taken lots of pictures along the way.