Twisted PTO Shaft

[Jimmyb33]

I was doing some brush hogging today. All of a sudden I got a bad vibration from the back end. I turned around to see my PTO shaft twisted and about to come apart. I didn't think I was working in very heavy stuff. I don't think the slip clutch is working too good.... Time to go shopping
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[greg_g]

I don't doubt you're right about the slip clutch, that's why at least annual maintenance is recommended. But I also see two other things: (a) the PTO shaft is too short. I don't consider what's left inside to be sufficient overlap, and (b) the rust pattern suggests pretty strongly that it's been bent in that same spot at least once before. Don't be tempted to get a replacement that's too short. It's always better to have to cut a new shaft down - than it is to have that same thing happen again.

//greg//

 

[jenkinsph]

I agree with Greg, and suspect this short socket of the shaft is what caused the problem. Just make sure you have enough play to allow for fully raising and lowering the implement without binding the pto. Most of the time if you allow an inch of clearnce between the tractor pto end and the edge of the pto shaft coupler to uncouple you wind up with about four inches of play when hooked up.

 

[Jimmyb33]

Thank you both for the feedback. I'm still new at all of this tractoring stuff, but am learning allot from the fine folks here. I bought the brush hog a couple of years ago and have just used it as I got it. I'll be sure to get a long enough PTO shaft next time. I saw someone on this site who sell's PTO shafts on their web site. Anyone know who that was?

Also, I have no idea how to remove that slip clutch from the gear box. Anyone have any pointers from a newbie???

Thansk!
jb

 

[IslandTractor]

I'm not so sure that PTO shaft is too short. It presumably twisted right at the junction of inner and outer shaft parts and that seems to be right at 50% mark of the outer shaft.

 

[jinman]

You can buy complete PTO shafts at Tractor Supply. If you want to save that clutch, you'll have to do some modification because the new shaft will come ready to slide onto the input shaft to the cutter and use a shear bolt. That's if the gearbox has a round shaft and it's the correct diameter. Also, most/all shearpin shafts will have a groove for a "C-clip" on the end of the shaft so that when you pop a shearbolt, the PTO shaft doesn't jump off the cutter and start flopping around (very dangerous). You might be better off to get a replacement for the shaft that is twisted and then clean and adjust your clutch. That's what I think I'd try to do.

Also, I've had several instances where I raised my cutter too high and the top/front of the cutter came up hard against the PTO shaft. I bent one PTO shaft so badly it looked like a playground jumprope. If you accidentally raised your cutter too high, you could have bent the tractor side shaft and got the twisting started due to weakening of the shaft at the bend point.

 

[Jimmyb33]

I got the twisted PTO shaft off the brush hog this weekend. Here's a pic of the input shaft.

The large diameter end is 1 3/8". Does anyone know whereI can get a replacement Slip clutch & PTO shaft for this type of shaft?

Thanks!
jb

 

[greg_g]

I Does anyone know whereI can get a replacement Slip clutch & PTO shaft for this type of shaft?

Others may have info to which I'm not privy. But to me, finding something compatible with that input shaft would be problematic. Are you sure you can't simply clean up and re-use the original slip clutch? Then you'd only be looking at replacing the PTO shaft.

//greg//

 

[Jimmyb33]

I've taken that slip clutch down as far as I can and the plates are just frozen/rusted together. i've beat on it and beat on it and am getting nowhere with it. I'm considering, for a last resort, cutting off the end of the shaft and drilling a hole in the 1 3/8" section to take a shear pin. But I'd rather get a slip clucth back on there.

Thanks for the input here!!
JB

 

[Transit]

I don't doubt you're right about the slip clutch, that's why at least annual maintenance is recommended. But I also see two other things: (a) the PTO shaft is too short. I don't consider what's left inside to be sufficient overlap, and (b) the rust pattern suggests pretty strongly that it's been bent in that same spot at least once before. Don't be tempted to get a replacement that's too short. It's always better to have to cut a new shaft down - than it is to have that same thing happen again.

//greg//

There is a minimum of overlap of the two half's of the shafts when extended to the max. For my KK it is 6 inches. You will need to know what is required for your shaft.

 

[pennwalk]

Agri supply (agrisupply.com) sells shafts. Looks like good prices. There is a hardware store here that has a pto shaft department. They have all the parts to fix a bent shaft. Any chance there is something like that around you?

Chris

 

[Jimmyb33]

I only have a Tractor Suply Co. near by. They have PTO shaft parts, but I'm pretty sure thay don't have a replacement slip clutch to fit the shaft on the brush hog. That's where I'm stuck at the moment.

Thanks!
jb

 

[jinman]

You say in your signature that it is a 5' Servis-Rhino shredder. I think you would be best served to get in touch with Servis-Rhino for replacement parts. They will no doubt be expensive, but may be less than your alternative. I don't see a simple way to change the input shaft. I think you'll have to change the whole gearbox. I would see about getting the driveshaft fixed and put a slip-clutch on the tractor PTO stub. Just let the cutter's slip-clutch remain frozen. You'll have to shorten the shaft a bit, but you'll have a working clutch and the protection you need.

 

[greg_g]

put a slip-clutch on the tractor PTO stub.

Dangerous suggestion. Especially if the slip clutch is sizeable enough that the PTO shroud has to be removed. Damned dangerous suggestion.

//greg//

 

[sweettractors]

What about repairing the old clutch with new discs and then cut out the bent/broken part of the hollow pto tubing. Then extend the pto to the correct length and slide a piece of black pipe over the outside diameter and weld in place? From the pictures the square drive is only at the very end next to the u joint. The best fix would be to go back to Servis-Rhino for parts and get your pto shielding back in place. Ken Sweet

 

[FastPauly]

Looking at the picture in post #7.....there are chains attached at the bottom of the bars that go to rear of the deck (3-point top link). I don't recall seeing this on any rotary cutters I have looked at. If the ground terrain promoted it, wouldn't this allow the rear of the cutter to raise well beyond what is normal as it would just freely pivot on the lower lift arms? Could this action be putting the PTO shaft in a condition that it can't handle?

Disclaimer; I don't even own a rotary cutter so an expert I am not.....just making observations and asking questions.

 

[blueriver]

I don't think the PTO shaft is to short, I also think the shaft got hit by the raising of the brush hog.

Go to a machine shop, they can and will cut out the bent tube and replace with a new one ... they may even rebulit the clutch.

 

[Transit]

I don't think the PTO shaft is to short.

No way to know unless you measure the shaft overlap.

 

[IslandTractor]

No way to know unless you measure the shaft overlap.

The twist was about half way up the female shaft which means the male shaft was about half way inside. That is not too short.

 

[Jimmyb33]

First of all, I'd like to thank you all for your input here. It has been helpfull in giving me a path forward.

I have contacted Rhino to see what their advice will be. We'll see what they say.

I have tried to seperate the inner PTO shaft from the tube and as of right now, it's stuck on there pretty good. I didn't try too hard because my first thought was to trash it and just get a whole new set-up. I'll give it another go soon and see if it will come apart. I'm thinking the twist has the end of the inner shaft enough to bind it in there.


If Rhino doen't have a good solution, I'm looking at two other options:

One, try again to get the slip clutch apart and rebuilt and just put a new PTO shaft on there.

Two, cut the end of the gear box shaft off and drill a hole to make it a shear pin set-up.

What are the thoughts on option two??

Thansk again guys! You've all been a big help.

JB