J80U PTO doesn't stop turning when unloaded

[russ_alabama]

My distant cousin Lance (close friends with he and family)... one of the sons bought a J80U Case IH tractor out of Oklahoma (we live in North Alabama).  Cab and 4wd. 

Got it in and they're cleaning it up, checking things out.  One thing is that the PTO shaft never stops turning when running and when unloaded.  If you shut it down and then hook up a load, like a bush hog, then crank it up, it's not turning.  Pull off the shaft, it'll turn.  

He was asking that I post it for some ideas on cause and what a fix entails (adjustment, more than that, etc).

Thanks in advance.    

EDIT:  That's with PTO turned off... probably was implied... and with PTO on, it pulls a load.  

Edited August 16, 2022 by russ_alabama
missing information

[CIHTECH]

Would have to look up said model number but a lot of those early tractors like that had a dual stage clutch with a separate lever to control pto, instead of (2) stages in foot pedal. Get under it and have somebody operate linkages and see whats going on, you may just need to give it a little more free travel. 

[495man]

If it's a JX80U it should be electrohydraulic shift on the right fender. 

Guessing something like a PTO brake is worn. 

[DT361]

Maybe an o-ring could have failed in the brake piston? 

I also had similar on my 1206 when the clutch linings started to shed from their backing plates - the linings would then "stack" and jam up what should have been free play in the clutch pack when not engaged.  Would overcome the brake pistons' friction, but not an implement's drag.  Engage it and the piston would clamp and it would operate, seemingly, normal.

I've never worked on that style of tractor, but watching a short video clip, seems like it is really easy to access the brake piston on the side, and to remove the driving shaft/cover and clutch assembly out the back....just some bolts and snap rings?

 

Mark

[russ_alabama]

8 hours ago, DT361 said:

Maybe an o-ring could have failed in the brake piston? 

I also had similar on my 1206 when the clutch linings started to shed from their backing plates - the linings would then "stack" and jam up what should have been free play in the clutch pack when not engaged.  Would overcome the brake pistons' friction, but not an implement's drag.  Engage it and the piston would clamp and it would operate, seemingly, normal.

I've never worked on that style of tractor, but watching a short video clip, seems like it is really easy to access the brake piston on the side, and to remove the driving shaft/cover and clutch assembly out the back....just some bolts and snap rings?

 

Mark

I saw that video and was surprised that it was all seemingly accessible without getting too deep.  His dad has a JX75 since new and has liked the tractor.