806 pto turns on sometimes while driving.

[Daniel Chestnut]

While using my 806 last fall on the grain cart, if I would happen to go over a bump or rough terrain the pto would sometimes turn on. Evidently the lever came up just a little, cause I would make sure it was down and the pto would go back off. Pto has completely been rebuilt. The spring that holds against the pto lever below the seat is good. I thought maybe there was an adjustment on the brake, but so far am not having any luck on finding anything or anyone that has ever had this problem. Anyone have any suggestions? Thanks in advance.
 

[Bob3 Martin]

Never had that happen on mine, Dan. That's a hydraulic driven clutch pack. If it's just been rebuilt, things are likely tighter than they used to be.

I would look at the linkage that turns it on and put a little more play in it.
 

[mazemeister]

check the control valve adjustment. there is a "feather" position with one pressure setting and "full on" with another... sounds like when the handle is "off" maybe there is just a little pressure getting to the clutch pack?

except there is a spring that holds the valve "off". hmmm... the brakes are spring applied, hydraulic removed, no adjustment.

maybe the brakes are weak? try this, with the tractor off and nothing hooked up, try twisting the pto shaft with your hand. your hand shouldn't be strong enough.

just brainstorming...
 

[the tractor vet]

Now this is a new one on me also . And the only way i could check it would be to install a gauge and drive it over about the same conditions and see if there is a pressure spike . and to be sure that it is not from lever bounce use the old tarp strap trick to hold it down in the off position .
 

[pete 23]

What kind of a lever do you have for putting pto in gear. I used to install the type used on later tractors with cabs and that lever was a little bit front end heavy. In other words, if you did not have a good return spring on the lever it would engage really easy. I always put a return spring on the linkage right at the pto to make sure the valve stayed down in off position. I saw a few pto's burn up the clutch packs and the operator never even used the pto because it takes about 20 psi to release the internal spring loaded brakes but only about 10 psi to apply some pressure to the clutch pack so it would be partially engaged even though not turning output shaft. Of course, the usual culprit was dirt under the boot or spacer. If that clutch return spring inside clutch pack is weak from heat it takes very little pressure to put a little drag on those clutches.