Ford 860, PTO Flail Mower disengages pto under load

[cerestes]

We recently purchased a Ford 860 with an Alamo SHD flail mower attached.

In general the tractor starts up and runs fine. Mower pulleys turn easily by hand. Tractor PTO engages, spins up mower, etc. If run through short (<6"?) pasture, it seems to run flail as expected.

Unfortunately, if run through grass much over 6-12", the lever that engages the PTO pops forward and PTO disengages.
With a bit of force (my foot) on the PTO, I can keep in engaged, but I can actually feel the lever trying to press against my foot to disengage.

Any suggestions where to start?

 

[RickB]

Typically indicative of a twist in the front end of the PTO output shaft. Available commonly and inexpensively as an assembly including shaft, bearing, seal, retainer and gasket.

 

[cerestes]

From the little reading I've been able to do, replacing the shaft doesn't look that hard, I just didn't want to throw money at it if it wasn't the problem. Would a shaft be visible twisted if I pulled the old one out?

 

[cerestes]

Would this be the part kit that I'm looking for? It feels a bit odd, in that I'm trying to replace a shaft, not convert the size of one.

Ford 860 PTO Shaft, Conversion Assembly - NCA700-38

 

[RickB]

A shaft twist should be visible. You are looking at the correct replacement.

 

[cerestes]

Alright. I'll get one ordered.

Until I can get around to replacing the shaft, if I force it to stay engaged with my foot on the pto lever, will that risk damaging a different part? Looking at a parts diagram, thinking something like the shifter fork.

I'm not finding PTO Shift Lever Assembly pieces as easily as I found the shaft.

 

[Soundguy]

here's a test. grab the pto stub at the back of the tractor ( tractro not running ). see if it pulls in and out. if yes, even 1/4" then it will walk itself out of engagement.

As Rick said. replacement is the easiest fix, otherwise you have to pull it and then decide if it is a shaft issue, or bearing, or retainer ring, wear ring or damaged bearing carrier. Some of those are cheap fixes, however the new shaft assy shotguns all the possible parts that could be bad in one slide out / slide in repair.

yes, you can bunji the engagement nadle in place to keep it from going out, but keep in mind the parts are still walking, and eventually you will / can wear the sliding coupler and possibly mushroomthe end of the pto shaft making extraction difficult.

 

[Kirk-NJ]

Here's what a twist shaft looks like. Pretty easy to drain fluids and pull your shaft to see if this is your problem.

Kirk

 

[cerestes]

Finally got a bit of time to play with the tractor this evening.

Drained fluids & pulled shaft. It doesn't appear to be visibly twisted, but it seems like it may be missing two snap rings.

The image here shows starting from the inside of the tractor, a shaft snap ring, and an outer snap ring, then the bearing. The inset image shows another snap ring, on the other side of the bearing.


On mine, from the inside of the tractor I think I just see one snap ring, on the tractor side of the bearing.
Shaft/snap ring/Bearing from the tractor side:


Shaft/no snap ring/bearing from the implement side:


Am I just missing a snap ring on the implement side? Is there a supposed to be a third snap ring 'shaft snap ring' too?

 

[Soundguy]

you have the snap ring on the tractor side of the bearing.

ont he other side of the bearing you have the wear ring.. you look to have about 1/4" of thrust play.. sot hat wear ring has moved.. which is common.

the other snap ring is past the seal int he bearing carrier housing.

the inset shows an outter snap ring, which iis also shown in the lower picture.

the big snap rings are int he bearing carrier housing.