BREAKING NEWS!!!!.......

[BTDT]

Or maybe it should read broken news. Went out to clean vines off of pto shaft on mower where they had wrapped around it (don't you hate it when it does that). Well, the bolt that holds pto coupler from mower to shaft was missing. Normally, you have a spring loaded pin thing you push in to hold it in place (that is missing as well). I have seen these replacement parts at TSC, but didn't know which one I needed without having the part, so I have just been using a bolt. Works ok, as long a bolt stays in place. Well, upon further inspection, the splines on the pto shaft are worn so, that evidently when mower gets into thick brush, contacts a small tree, etc, it is slipping/spinning on the splines and shearing the bolt. I used a mirror to see where I couldn't get my head, and sure enough there is only about 1/2 of the thickness of the spline left. I have pics, but am at home and this computer doesn't recognize my camera, so I'll post pics tonight when I get to work. So as they say on the news stations, "Tune in tonight at 6pm for the full story (pics)".

This is on a rotary cutter attached to an H Farmall.

 

[BTDT]

Ok, on with the report. First pic is pto coupling showing missing bolt and spring loaded pin. Pic 2,3,4,5 showing how I used mirror to see between back of tractor and pto coupling to take a picture of how it is worn when mated together. Pic 6 shows end of coupling and shaft separated. Pic 8,9 showing width of spline and how it tapers from seal to end of shaft. Pic 10 is how a good shaft is supposed to look (this is on my M Farmal)

 

[KYErik]

Is there a shear pin or slip clutch "upstream" from this worn joint?

That joint doesn't look like it was ever designed to slip so a cheap fix would be to drill the hole out slightly larger and use a grade 8 bolt to keep it from slipping, but only if the gearbox was protected with a clutch/shear pin somewhere else.

 

[RickB]

Is there a shear pin or slip clutch "upstream" from this worn joint?

That joint doesn't look like it was ever designed to slip so a cheap fix would be to drill the hole out slightly larger and use a grade 8 bolt to keep it from slipping, but only if the gearbox was protected with a clutch/shear pin somewhere else.

That's not only a cheap fix,but a poor one that won't be satisfactory. There is so much slop in those splines that a bolt simply will not carry the load for very long. You need a new tractor end yoke on the implement drive shaft at the very least, and you should really find a better used output shaft for the tractor. Give some thought to replacing the yoke that has the u-joint cap welded to it as well. Just fix it properly and be done with it.

 

[shaley]

I'd pull the PTO shaft and have one made. Surplus Center sells splined shafting which could be turned to size at a machine shop. Probably for less than $100

 

[BTDT]

That's not only a cheap fix,but a poor one that won't be satisfactory. There is so much slop in those splines that a bolt simply will not carry the load for very long. You need a new tractor end yoke on the implement drive shaft at the very least, and you should really find a better used output shaft for the tractor. Give some thought to replacing the yoke that has the u-joint cap welded to it as well. Just fix it properly and be done with it.

When I replaced the u-joints a couple weeks ago, if I had of known that the shaft and coupling were worn that bad, I probably would have just went with a new shaft at that time. But that's the way it is with old iron, you fix something and then realize that there is something else that needs fixing/replacing. Oh well, gives me something else to put on the to do list.

 

[KYErik]

That's not only a cheap fix,but a poor one that won't be satisfactory. There is so much slop in those splines that a bolt simply will not carry the load for very long. You need a new tractor end yoke on the implement drive shaft at the very least, and you should really find a better used output shaft for the tractor. Give some thought to replacing the yoke that has the u-joint cap welded to it as well. Just fix it properly and be done with it.

RickB- You are correct and I completely agree, it might not last a long time with heavy cutting cutting loads, but it should last a bit longer than his current fix. I should have prefaced my suggestion with "cheap and longer lasting temp fix"

I have another low budget solution if my first solution is too temporary. If you are going to replace the yoke and worn gearbox shaft (lots of $) you could center the yoke on the shaft and carefully weld them together making sure you don't over heat the gearbox input bearing (use short bursts).

If you need to take the gearbox apart in the future, just use a sawzall to cut the input shaft between the gearbox bearing and the weld holding the yoke onto that shaft. Yes, this will destroy the input shaft- but you are getting away with not replacing it now and maybe it will last another 30 years! (the glass is half full)

BTDT- I also work with old iron, my farm tractor is a 1943 Case and all of my hay making equipment is over 30 years old (I still use a NH 68 baler). I have a personal philosophy with my old iron. I am on a tight budget and I can either pay lots of money and spend lots of time looking for replacement parts (if they still even exist) and do the repair right so I never have trouble with it in the future. Or, I can think outside of the box and come up with a cheaper temporary "field" fix that I might have to redo later on- as long as it doesn't damage something else or endanger me.

Attached is my hay rake rotten tire fix. That is a 30 inch rim- a specialty order tire/tube that are about $200. My view is this- why put a $200 tire on my working worn out $60 hay rake (scrap price- I doubt anyone would buy it for use as a rake) when all I need to do is add another 50 cents of duct tape every cutting to hold the tread on. Its been this way for 4 years and has raked 700+ bales worth of hay. Too bad the handle "farmwithjunk" is already taken, or else I would have it...

 

[SkunkWerX]

I agree with RickB, this is a case where the permanent fix is the correct and really, only fix for this issue.

The output shaft on the tractor shouldn't be too bad to replace.
I'd check around with the FarmAll crowd, there may likely be sources for new and used/but still serviceable parts.

Good Luck, this is a case where you will be glad you did it, once you replace that output splined shaft.

 

[Soundguy]

I gotta agree dead on with Rick.

Coupler is shelled out.. probably why the pto spline is worn so bad.

New output shaft is about the best fix for the tractor.. therea re a few other 'around the elbow' things you could do it this part were NLA.. And a new yoke end for the shaft is gotta be on the menu as well.

Soundguy

 

[KYErik]

I apologize guys.

I mistakenly thought that we were looking at the worn splines on the input shaft to the bushhog gearbox. I didn't realize that this was a worn tractor PTO output. I should have looked at pic #9 more carefully. I was surprised at first to see that since splined shafts aren't usually seen on gearboxes unless something is 50+ years old.

Please disregard my suggestion to weld the yoke onto the PTO shaft or to drill/use a bigger bolt. Either would be a foolish thing to do to your tractor PTO output shaft.

Everyone else is correct, you'll have to replace the tractor's PTO shaft.

Someone might suggest that temporary repair would be to weld on PTO extending adapter if it is impossible to find a new PTO output shaft (I know it sounds bad but its better than junking the tractor). But that's not officially coming from me... smile...