Ford 860, PTO Disengages under heavier load?

cerestes

New User
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 seemed 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 manual 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?
 
First make sure that the PTO shaft to the mower isn't too long or not sliding smoothly along its length so that it's not putting undo force against the end of the tractor's PTO shaft. Then disconnect the mower's PTO shaft from the tractor and check the tractor's PTO shaft for excessive for end play (forward/rearward movement).
 
The mower shaft seems to be ok. If disconnected from the tractor it easily slides along its length, and can get a good bit shorter or longer than is necessary to connect to the PTO.

When the shaft is disconnected, I can slide the end of the PTO shaft in/out a small amount - maybe 1/2 an inch from fully in to out. How much play should it have?

 
If the PTO shaft move a 1/2 half in and out then that is where the problem is. It should have less then an 1/8 inch of play in not even less then that but do not have my manual handy to look to be sure exactly how much is to much
 

Another forum mentioned problem was likely a twisted pto shaft. Would replacing that resolve the problem with too much play in/out? Or is it possible I can remove/reinsert the old one and fix something that would correct the play?
 
With out finding my manual I can only give you a maybe type of thing but it could be as simple as a snap ring that need to be replaced or a bearing or both. You need to buy an I-T FO-20 shop manual and it will show you the parts break down of the shaft. Not a hard job the check it out you remove the bolts on the end plate the PTO shaft is in and pull it out. Then look it over to see what is wrong. If you want send me an e-mail and I'll go out and bring my manual in and then send you the page out of the manual so maybe you can fix it sooner then having to wait to find a manual
 
I do have a manual for the tractor. I took a picture of the PTO shaft page and tried to attach it.

I'll be the first to admit, I haven't done much more than car oil changes or brake replacements before. On one hand it seems simple - on the other hand references to custom bearing pullers and step plates makes me a bit nervous.

 
35540.jpg
 
That manual covers the hundred series, the '01 series and the 4 cylinder 2000 and 4000 series tractors that were made at various times from 1955 through 1964.

That page that you posted from the manual says "two speed PTO shaft" at the top, so that is not for your 860. The only models that had a two speed PTO were the x81 models (681, 881, etc.) with the Select-O-Speed transmission.

Your 860 has a single speed 540 RPM Live PTO so you need to find the proper drawing and instructions in the manual for that. It will be similar to the page that you posted, but not exactly.
 

Sorry, the photo was really deceptive. Right above the photo was the image for the two speed PTO figure 2'. The instructions are for a 'single speed pto overhaul' and the photo shown was 'Figure 3 - Single Speed P.T.O. Shaft'.

That all said, what part would potentially fail and allow the shaft to have too much play?
 
Thrust play is usually a slipped split ring, wear ring or worn bearing. A twisted shaft isn't going to significantly shorten.

Check pto lever detent after correcting thrust play.
 

If I can get the time, I'll pull it apart on Sunday. Is this really potentially as simple as a c-clip (snap ring, jesus clip, etc) that can pop out of a groove in the pto shaft?
 
I just pulled the PTO out of an 841 that was moving in and out about 5/8's of an inch. The seal sleeve had moved that amount once I could see it out of the tractor. This PTO shaft had been ruined by an over running clutch. The guy I bought it from failed to mention a lot of things. Go figure.

Steve
 
the end play of the PTO shaft is controlled/adjusted by the 'sleeve' which is a press fit over the shaft - it's not a particularly tight press and can be adjusted with a hammer and a fixture made from 1 1/2" pipe if you're handy that way -

In this case I'd suggest you remove the shaft from the tractor and evaluate the bearing and seal - both are relatively cheap if the unit is leaking any oil or the bearing is at all rough -

biggest challenge may be to get the bearing housing (called 'cover' in your picture) loose from the differential housing, it tends to be a bit tight - remove the hitch and then remove the 4 bolts holding the PTO bearing housing to the differential housing - with a soft hammer (brass) or a block of wood and a hammer tap the 'points' of the housing and try to get it rotating a bit - if you can make it move a little then you can try to get between the housing and differential with a thin blade and work the assembly out - I've seen lots of 'covers' with corners broken from ill-advised prying - take your time -

after you get the PTO shaft assembly removed from the tractor, pry the outer snap ring loose and this will allow the cover to slide off the shaft/bearing toward the rear - the seal is easily replaced at this time - spin the bearing with your hand, it should be 'silky' smooth - if not it's time to replace - inspect the sleeve for grooves or pitting - it's not particularly expensive either - if the bearing and sleeve are in good shape, take a short piece of 1 1/2" pipe, slide it over the end of the shaft and against the sleeve and tap the sleeve until it just touches the bearing (a hydraulic press is handy here if you have one)- it'll move more easily if it's hot - doesn't need to be red, but a modest application of a torch will loosen it right up -

which is the way to remove it if you want replace the bearing and/or sleeve -

if you're intimidated by the previous you may just want to take the shaft assembly to a mechanic/machine shop -

really, for the price of things, if you're going to remove the shaft from the tractor, I'd replace the bearing and seal and sleeve - then it's ready for the next 50 years -

good luck -
 
I have a 64 ford 4000 cyl that was doing the EXACT same thing - kicking PTO out of gear in hard pull or in a corner. It had 1/2 to 5/8 in and out freeplay. I pulled the 4 bolts and PTO shaft out and found the large OUTER snap ring was gone... not only was it gone, but the last 1/8 inch of the back of the round housing where the snap ring groove used to be was COMPLETELY MISSING!!! someone had replaced the shaft, bearing and small retainer on the shaft but did not install the large outer bearing retainer because there was NO GROOVE for it anymore! I bought a new housing, put the shaft and bearing in it, installed the outer large snap ring and IT WORKS GREAT. Housing and snap ring was about $90.
 
small c clip holds shaft against the innner bearing race.. which is held inplace by the housing by the larger c clip on the outer bearing race... so could be smaller clip, larger clip, or groove in shaft bad, groove in housing bad, or bearing bad..

so pulling and inpecting will show where the play comes from. sometimes simple as fishing for a c clip in the bottom of the reservoir... sometimes a broken housing groove letting the bearing move...

sometimes a twisted shaft end and or coupler damaged.

but the play is excessive and the movement will cause the coupler to slide off and disconnect the pto..
 

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