Jumped on the old Yanmar, it’s been a while, and the clutch would not disengage to shift. Figured stuck clutch, ran it around trying to unstick it but no luck. Clutch pedal felt very easy? Decided to just get a new clutch kit and fix a few other leaks while I have it down. Pulled the motor, removed the clutch and it did look like it had been stuck but a lot of left over meat on the disk. Installed the clutch kit put the motor back in but the clutch pedal feels the same, I can push it down with my hand with ease? Checked all the linkage and pins were in tack and all looked good. Put it in the air and was able to turn the tires in neutral, stopped in gear, pushed in the clutch still couldn’t turn the wheels? Seems to me nothing changed? That easy clutch pedal worries me even after adjusting. Any ideas or checks that can locate the issue? Thanks!
Chewwy
Platinum Member
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Sounds like something is going on that is preventing the linkage from the clutch pedal fully engaging the clutch fingers via the throw out bearing.
Not familiar with the Yanmar setup but typically there is some sort of adjustment in the linkage that is used to get full clutch engagement and full clutch release.
Not familiar with the Yanmar setup but typically there is some sort of adjustment in the linkage that is used to get full clutch engagement and full clutch release.
Harry in Ky
Veteran Member
This is a "suddenly appeared" problem? You split the tractor, replaced clutch disc AND pressure plate? (Clutch "kit" usually includes both as well as both bearings)
The old pressure plate did not appear to be broken or damaged to speak of? Now it still has the same "feel" and same problem?
Next time you split it pay more attention to the cross shaft, release fork, and the connection between the two.
The old pressure plate did not appear to be broken or damaged to speak of? Now it still has the same "feel" and same problem?
Next time you split it pay more attention to the cross shaft, release fork, and the connection between the two.
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I was going to say "check slave and master cylinders", but that comes from working on a lot more cars than tractors. 
There's no view port in the bellhousing, where someone can see if the fork is actually moving the throwout bearing?
There's no view port in the bellhousing, where someone can see if the fork is actually moving the throwout bearing?
Clutch disk had a lot of material on it still but you can see where it was sticking on the flywheel and pressure plate. When removing pressure plate it seemed worn out, it didn’t have much pressure on it when removed. Replaced with kit including pilot bearing. Mechanical clutch so linkage and checked fork, all straight forward and looks fine. It’s not completely back together so if I had to split it again no issue.
If I can’t turn the wheels when in gear I should be able to push the clutch in and spin them. I can spin the wheels in neutral.
I’m thinking I need to split it again and check all the clearances again unless I’m missing something?
If I can’t turn the wheels when in gear I should be able to push the clutch in and spin them. I can spin the wheels in neutral.
I’m thinking I need to split it again and check all the clearances again unless I’m missing something?
You’re right, I’m overthinking because I really don’t want to split the case again but it’s mechanical linkage, it’s straight forward, just need to take all the measurements. Thanks for the reply!
Chewwy
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With mechanical linkage, I would typically adjust so there is maybe 1-1/2” to 2” free play in the clutch pedal before the throughout bearing engages the pressure plate fingers. Not sure the service manual would provide this info.
ruffdog
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Tell us about the throwout bearing. Did the kit come with one? what was the shape of the old one? Is the fork engaging the TO bearing correctly?
I’ve attached some measurements that hopefully make sense. Compared parts to those removed and are the same. The parts removed showed no signs of damage for the exception of the thin layer of clutch disc material stuck to flywheel and pressure plate. Kit came with pressure plate, disc, throw out bearing, and pilot bearing.
The clutch not disengaging was the original problem. Clutch pedal went right down and never felt any resistance. Adjustments to linkage did not work. Split the case again and took these measurements which to me tells the story why the clutch does not work but not how this could happen. According to these measurements the throw out bearing is not touching fingers of pressure plate with clutch pedal all the way down? I measure 3 and 4 times and always the same.
Harry in Ky
Veteran Member
How does the fork fasten to the cross shaft? Pinch bolt with a dimple in the shaft? Keyway with key stock? Roll pin (hope not)? If you can't get enough adjustment using the pedal free play adjustment to get the clutch to release properly (and the problem was present with the previous clutch) I'm still betting the issue is between the cross shaft and the fork.
Attached with roll pin. They are intact, removed and replaced because I could, forks have a little wear nothing major. Makes sense about the cross shaft because I could tell the difference in the clutch pedal, felt like the clutch was slowly going away. I’ll remove it and check to see if it hasn’t somehow twisted or something. Thank for the reply!
Fork is fastened with roll pin to cross shaft. I pulled out cross shaft and forks, all looks solid, a little ware on forks and throw out bearing but nothing crazy. With the clutch pedal all the way down and linkage adjusted as far as it can, I’m stumped!
Harry in Ky
Veteran Member
Well it's obvious SOMETHING changed. The clutch was working fine one day and suddenly it's like this. You've changed the pressure plate and gain nothing. That says the problem must be in the geometry of the linkage between the clutch pedal and the cross shaft, the cross shaft and the fork, the fork and throw out bearing and/or the sleeve it ride on. No matter how many ideas get floated past you here, you're still the only one looking at it.
As a general rule whenever I have a tractor split (for clutch repair of any kind) before I roll it together I will take a tape measure and measure from the tractor split mating surface back the contact surface of the pressure plate release levers. Whatever that takes. Sometimes it requires getting a little "creative". Then do the same measuring from the split surface to the face of the throw out bearing. If the two measurements aren't within 1/8" of each other with room in the pedal adjustment to go both ways I stop right there and find out why.
As a general rule whenever I have a tractor split (for clutch repair of any kind) before I roll it together I will take a tape measure and measure from the tractor split mating surface back the contact surface of the pressure plate release levers. Whatever that takes. Sometimes it requires getting a little "creative". Then do the same measuring from the split surface to the face of the throw out bearing. If the two measurements aren't within 1/8" of each other with room in the pedal adjustment to go both ways I stop right there and find out why.
Gord Baker
Platinum Member
I don't know what is involved with a 'Clutch Kit' but it sounds like a bent or broken 'Clutch Fork' or a failed Pressure plate.
Some pictures would be nice. Sheared roll pins are the number one suspect, for sure. You've verified them all, so we can move on.
The crank arm attached to cross shaft, does it move up and down with the clutch pedal? I'm not particularly familiar with this tractor, but I assume the crank arm should be moving at least 3-4", measured at the linkage end. If the crank arm is moving in sync with the clutch pedal, then I would be suspicious that the crank arm has somehow spun on the cross shaft. Looking at an old video of a clutch replacement on YouTube, it would appear that the correct orientation of the crank arm is parallel with the roll pin that holds the clutch fork.
The crank arm attached to cross shaft, does it move up and down with the clutch pedal? I'm not particularly familiar with this tractor, but I assume the crank arm should be moving at least 3-4", measured at the linkage end. If the crank arm is moving in sync with the clutch pedal, then I would be suspicious that the crank arm has somehow spun on the cross shaft. Looking at an old video of a clutch replacement on YouTube, it would appear that the correct orientation of the crank arm is parallel with the roll pin that holds the clutch fork.
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Actually happened with my loader control, once. Took a few minutes looking at all the linkage, wondering why the stick was all sloppy despite everything else being tight, until I caught the pivot point wobbling.
