Pulling apart PTO shaft

jjp8182 · Mar 28, 2020

Not sure why/how it happened, but when I went to hook up the PTO shaft on the finishing mower this week the PTO shaft was stuck and wouldn't extend. It's been sitting under cover (inside a carport with the tractor) since late last November.

So I used this little set up to pull it apart

- as I figured it would avoid damaging any of the trees in the yard, and the weakest link in the whole thing was either going to be the PTO shaft coming apart or the tow strap (which is rated for a 3,333lb working load).

Even after getting apart I can't say I really understand what it was that caused the PTO shaft to stick ..unless the grease that was on the shaft had just picked up enough dirt to create a friction/vacuum bond that needed a little extra persuasion to extend (?!?!)

At any rate this pulled the shaft apart in short order -- it actually took longer to set up (given I had to remove the grab hooks to feed the chain through) than it did to pull the shaft apart. After which I de-greased and cleaned everything up before spraying the shaft down with lithium grease and reassembling.

So my questions are: Has anyone else had something like this happen with a PTO shaft inexplicably getting stuck? and what sort of grease do you use on your PTO shafts?

Peter 315 · Mar 28, 2020

I use fluid film on the sliding part , reg grease in the u joints....

crazyal · Mar 28, 2020

Looks like black rust to me. Black rust happens when there's limited amount oxygen getting to the steel. Does your shaft have a grease fitting? If not I would make sure to take it apart at least once a year, clean off the old grease and grime, and put it back together. I use the same grease that I use elsewhere on the tractor. But if I was going to get a specific grease I probably would get marine grease since it's got additives to protect against rusting.

Sawyer Rob · Mar 28, 2020

I NEVER pull on the U-joints, you can damage them fairly easy... Wrap your chain around the shaft "behind" the u-joint...

I don't like grease on pto shafts, I clean them up and then spray them with WD40 or similar, every time I put them together, they are left apart when off the tractor.

SR

RustyA · Mar 28, 2020

Used to happen to my seasonal hay equipment and brush hog. Started using penetrating oil on shaft and elevating shaft and wrapping end in plastic. Never had one stick after that.

Farmer495 · Mar 28, 2020

Use plain grease for years, never had one stick yet...but any PTO shaft machine is stored inside.

jjp8182 · Mar 29, 2020

crazyal said:
Looks like black rust to me. Black rust happens when there's limited amount oxygen getting to the steel. Does your shaft have a grease fitting? If not I would make sure to take it apart at least once a year, clean off the old grease and grime, and put it back together. I use the same grease that I use elsewhere on the tractor. But if I was going to get a specific grease I probably would get marine grease since it's got additives to protect against rusting.

That makes a lot of sense as the u-joint ends are sealed with no grease fittings on the shaft - so having a layer of grease between the two shafts would probably help create a situation for little/no air to flow through. Which would also help explain why I didn't see any red-colored rust (I can't recall ever hearing of black rust before).

Thanks for the info - and confirming my thought that an annual cleaning may help prevent future problems.

Dave M7040 · Mar 30, 2020

jjp8182 said:
That makes a lot of sense as the u-joint ends are sealed with no grease fittings on the shaft - so having a layer of grease between the two shafts would probably help create a situation for little/no air to flow through. Which would also help explain why I didn't see any red-colored rust (I can't recall ever hearing of black rust before).

Thanks for the info - and confirming my thought that an annual cleaning may help prevent future problems.

Fyi re black rust.

Ferric means the iron(III) ion Fe+3, and ferrous means iron(II), which is Fe+2. ... Ferric oxide is Fe2 O3, and ferrous oxide is FeO. Ferrous oxide is reddish in color and is known as the mineral hematite. Ferric oxide is black and is the mineral wustite.

Dave M7040