Willl
Elite Member
In a nutshell, Tech said to back it off some so the throw out bearing doesn't contact the clutch and spin while the clutch is out.
jd 850 pto question--doesn't ease into gear
- Thread starter Niji
- Start date
Alright...clutch rod is back where it was before.
When looking through the access hole in the bell housing I don't seem to see what Tech describes. I'm looking at the space behind the flywheel. I can only see the very back surface of the flywheel. If I turn it, I do see the heads of bolts that are about 1/2" in size. But there seems no way to know about spacing between plates, and certainly no way to see or access any lock nuts on the hidden side of the plates towards the front of the tractor.
I keep looking around to see if there is some other access plate and I'm in the wrong spot, but there doesn't seem to be.
I did notice that the rod I adjusted goes from the clutch pedal forward, but there is also a rod off the same pedal under the floorboard that goes to a lever towards the back behind the transmission shifter, which has an adjustment as well. I just wondered if that was specific to the pto?
When looking through the access hole in the bell housing I don't seem to see what Tech describes. I'm looking at the space behind the flywheel. I can only see the very back surface of the flywheel. If I turn it, I do see the heads of bolts that are about 1/2" in size. But there seems no way to know about spacing between plates, and certainly no way to see or access any lock nuts on the hidden side of the plates towards the front of the tractor.
I keep looking around to see if there is some other access plate and I'm in the wrong spot, but there doesn't seem to be.
I did notice that the rod I adjusted goes from the clutch pedal forward, but there is also a rod off the same pedal under the floorboard that goes to a lever towards the back behind the transmission shifter, which has an adjustment as well. I just wondered if that was specific to the pto?
Willl
Elite Member
An exploded parts view of that tranny would be really helpful right about now.
irwin
Veteran Member
You can see the dual clutch in Deere's parts look up. Not very clear but here it is.
John Deere - Parts Catalog
John Deere - Parts Catalog
irwin
Veteran Member
I've looked but I don't see any adjustments on the clutch itself. I gave my repair manual for my 770 to the guy that bought it. The manual was for 770, 870, 970, 1070, 790, 990 (the 750, 850 etc.is the previous series to the x70's) but don't recall any internal clutch adjustment when I was studying it.
You might be able to get away with a half inch free play for a while. Try adjusting it like that. In the mean time..keep searching for info..you really need a repair manual..BTW this is a good excuse to buy one.
You might be able to get away with a half inch free play for a while. Try adjusting it like that. In the mean time..keep searching for info..you really need a repair manual..BTW this is a good excuse to buy one.
Willl
Elite Member
That might be your L/S brake rod.
Latest update: I've had to push a bunch of dirt around today for a new barn, so I just have a blade on the 3pt hitch and no pto driven implement yet, but it looks to me from watching the shaft exiting the tractor with no load on it that now, even though I have adjusted that clutch rod back to its original position, the 2 stage clutch is working the pto.
I wonder if either things were seized up in there and the mis-adjustment was enough to free them up and they're working now that they're re-adjusted...or if although the thread count put me back to the original position on the rod if perhaps I am slightly off, and that is enough to have it working?
Either way, it looks like I may be in business. I need to connect the pto to something and give it a proper testing before I get all excited again.
I wonder if either things were seized up in there and the mis-adjustment was enough to free them up and they're working now that they're re-adjusted...or if although the thread count put me back to the original position on the rod if perhaps I am slightly off, and that is enough to have it working?
Either way, it looks like I may be in business. I need to connect the pto to something and give it a proper testing before I get all excited again.
Trac-Tech
Bronze Member
Hi Guys
Thanks for the link to the JD parts catalog. Printed it off and I think I have worked it out. Here goes for a lengthy sort of explanation: -
1. Item # 37 is the PTO clutch plate and this is clamped to the flywheel by Item 36 and spring 29.
2. Item # 33 is the main drive clutch and is clamped to the false flywheel item # 35 by Item # 31 by spring # 29.
3. The three adjusting bolts for the second stage are item # 30 and there are threaded into item # 36.
4. When you push the pedal down, it pushes the three fingers (item # 24) forward which in turn pull the plate item # 31 rearwards away from the main plate to relaes it and give no drive.
5. At this point, the underside of the head of the three bolts (item # 30) are now in contact with the plate # 31.
6. As you push the pedal through the second stage, the three bolts are dragged rearwards as well and due to the fact that they are threaded into the plate # 36, the reacttion is to move the pale # 36 rearwards and release the PTO plate.
I hope that helps explain what is happening in there when you push the pedal clearly enough. As the main plate starts to wear, the pressure plate item # 31 moves forward to the front of the tractor because the clutch plate has become thinnere. The reaction on the fingers is to move rearwards and hence no free play and this is why there is external adjustment on the rod so that you can move the thrust bearing back as the clutch wears. Due to this action, the distance between the underside of the head of the three bolts Item # 30 increases and hence the pedal travel is not enough to disengage the second stage.
I am sorry about before as my description was not correct for this clutch and the one I was thinking of worked opposite way around and the head of the bolt pushed rather than pulled as in this one.
Now becuase I dont know the clearance setting under the head of the bolt, you can use my original description of tieing the pedal at the point you want the second stage to start, then loosen the locknut and screw the bolt in until the underside of the head of the bolts are just touching the plate # 30. This will be the point where it will start to release the pto clutch plate.
Looking on the clutch housing picture, it looks like the hole you are looking in is a little too far back and there may be no others. It is hard to believe, but nothing surprises me!! If that is the case, then the tractor will need splitting to carry out the adjustment and then you will need to know the exact setting.
Your assumption that you may have freed the plate may very well be correct and all should be good. The heavy duty main plate should be a cerametallic type clutch and wear will be kept to a minimum and hence even less need to adjust the second stage.
Once again, sorry for the long winded explanation, but I hope it has been helpful.
Cheers
Thanks for the link to the JD parts catalog. Printed it off and I think I have worked it out. Here goes for a lengthy sort of explanation: -
1. Item # 37 is the PTO clutch plate and this is clamped to the flywheel by Item 36 and spring 29.
2. Item # 33 is the main drive clutch and is clamped to the false flywheel item # 35 by Item # 31 by spring # 29.
3. The three adjusting bolts for the second stage are item # 30 and there are threaded into item # 36.
4. When you push the pedal down, it pushes the three fingers (item # 24) forward which in turn pull the plate item # 31 rearwards away from the main plate to relaes it and give no drive.
5. At this point, the underside of the head of the three bolts (item # 30) are now in contact with the plate # 31.
6. As you push the pedal through the second stage, the three bolts are dragged rearwards as well and due to the fact that they are threaded into the plate # 36, the reacttion is to move the pale # 36 rearwards and release the PTO plate.
I hope that helps explain what is happening in there when you push the pedal clearly enough. As the main plate starts to wear, the pressure plate item # 31 moves forward to the front of the tractor because the clutch plate has become thinnere. The reaction on the fingers is to move rearwards and hence no free play and this is why there is external adjustment on the rod so that you can move the thrust bearing back as the clutch wears. Due to this action, the distance between the underside of the head of the three bolts Item # 30 increases and hence the pedal travel is not enough to disengage the second stage.
I am sorry about before as my description was not correct for this clutch and the one I was thinking of worked opposite way around and the head of the bolt pushed rather than pulled as in this one.
Now becuase I dont know the clearance setting under the head of the bolt, you can use my original description of tieing the pedal at the point you want the second stage to start, then loosen the locknut and screw the bolt in until the underside of the head of the bolts are just touching the plate # 30. This will be the point where it will start to release the pto clutch plate.
Looking on the clutch housing picture, it looks like the hole you are looking in is a little too far back and there may be no others. It is hard to believe, but nothing surprises me!! If that is the case, then the tractor will need splitting to carry out the adjustment and then you will need to know the exact setting.
Your assumption that you may have freed the plate may very well be correct and all should be good. The heavy duty main plate should be a cerametallic type clutch and wear will be kept to a minimum and hence even less need to adjust the second stage.
Once again, sorry for the long winded explanation, but I hope it has been helpful.
Cheers
Attachments
Fantastic, Tech. Many thanks for that breakdown and tutorial. I've been tied up moving round bales and still haven't attached to the baler or another big pto machine--will try to get that done before dark today to be sure of my suspicion that the 2nd stage is fully functional.
But, it sounds like from your explanation that if I've got the exterior clutch rod adjusted back where it was with that play to avoid turning the throw-out bearing, and the 2 stage now works the pto, I should have not worries about messing something up in there. I'd of course like to put off pulling the tractor in half, but I'm up for it when the need does arise. I figure since there seems to be no other clutch trouble, I'll not go all-out on the little fellow now, and enjoy that newly discovered pto clutch.
But, it sounds like from your explanation that if I've got the exterior clutch rod adjusted back where it was with that play to avoid turning the throw-out bearing, and the 2 stage now works the pto, I should have not worries about messing something up in there. I'd of course like to put off pulling the tractor in half, but I'm up for it when the need does arise. I figure since there seems to be no other clutch trouble, I'll not go all-out on the little fellow now, and enjoy that newly discovered pto clutch.
Just to follow up...I finally got around to connecting the 850 up. I attached to my JD 1217 haybine, and the two stage clutch pedal works like a charm! I am much relieved, and now can ease into gear with this little tractor. Many thanks again for the advice. I still don;t know if it was ceased up in there and my adjusting broke it loose, or if it ended up ultimately slightly readjusted, but i seem to have all the basics covered now: 2 stage clutch, and enough slack not to turn the throw out bearing.