TRACTOR SLUNG PTO SHAFT!!! - PICS.

[Tinhack]

The clutch I bought off the Interweb came with the clip and instructions on how to install it. It also mentions how to adjust the clutch for your tractor. If you didn't install the clutch, I'd be talking to the guy that did--He owes you some new parts. If you installed it, it's on you.

You got off cheap! You're lucky it didn't take out rear housing on your tractor too.

 

[TexasDigger]

...I suggest you check your driveshaft to see if yours has that circlip or if it is missing.

As bad as this is, it could have been much worse. A new PTO plus all the other parts is going to be pretty expensive compared to the cost of that circlip.
...
Anyway.....look at your gear box shaft and you should see a retaining clip installed like this one....View attachment 750028

I just picked up 3 of these from TSC (1 for the gear-box shaft, 1 for the clutch shaft + a spare!). I MIC'd my grooves and came up at 1.29" so figured a 1 1/4 C clip would do the trick. Still haven't re-engaged the PTO after unhooking the shaft but will tonight just to make sure I don't hear gears grinding or any broken teeth noise.. The engine sounded fine but who knows if any long-term damage until it reveals itself (cracked crankshaft, etc). It all stopped VERY abruptly once it wound itself up! What !$#@$$es me off is that these shafts never had clips, came with clips from dealer - no mention of clips anywhere that I had seen on any vids, etc - nada. Pretty important safety feature that I have to chalk off to literal ignorance since I just didn't know. If I had ever seen them even in a package with other PTO adapters, etc., would have had a reference to put them back on - didn't even think about it and even though it seems like common knowledge, if it wasn't there to begin with when I took something off/apart, I didn't know to look for it missing. On a good note, whatever it broke is all replaceable. Could have been a lot worse.

https://www.tractorsupply.com/tsc/product/hillman-1-1-4-in-external-retaining-ring-1045512

 

[Tinhack]

Don't use grade 2 with the clutch. They won't last. Adjust the clutch.

 

[TexasDigger]

Don't use grade 2 with the clutch. They won't last. Adjust the clutch.

Noted. Will save myself the headache on worrying about putting sheer bolt back in it later. When I picked up the 1 1/4 clips, I also picked up both a Grade 5 bolt and a REAL Grade 8 bolt + lock washers/nuts (the lock washers & nuts were Grade 2, but assumed as long as they hold the bolt in place, that's what matters.)

Definitely adjusting the clutch once it's all back together. Have to go buy a straight piece of strap iron from the steel yard tomorrow and also some slightly stronger chain than what was originally holding rear of the RC. Looked at the RC a bit closer & all of the 4 point and rear chain brackets took a pretty good beating but nothing that can't be fixed. It actually straightened out my top-link mount for me that was clamping on the top-link making it hard to connect/disconnect so I'll take that as a positive!

 

[TexasDigger]

The clutch I bought off the Interweb came with the clip and instructions on how to install it. It also mentions how to adjust the clutch for your tractor. If you didn't install the clutch, I'd be talking to the guy that did--He owes you some new parts. If you installed it, it's on you.

You got off cheap! You're lucky it didn't take out rear housing on your tractor too.

It's on me. Adjusted per instructions but never "slipped" it. Will back off on them until I see it spinning & then tighten back up. Definitely will look up more "how to" on the clutch adjustment but the measurement specs that came with mine for spring height are too tight - although when I re-engaged the PTO I was at full operating RPM but I think the clutch is designed to accommodate for that since it has auto on/off option on my PTO (can turn on/off as I raise/lower the 3pt - a feature that I have yet to use!)... Definitely on me though for both the clutch adjustment and also will also own the blame for lack of circlip. I've seen that groove there plenty of times but just never thought "what's that there for?" since I never removed a circlip from it..

 

[ptsg]

It's on me. Adjusted per instructions but never "slipped" it. Will back off on them until I see it spinning & then tighten back up. Definitely will look up more "how to" on the clutch adjustment but the measurement specs that came with mine for spring height are too tight - although when I re-engaged the PTO I was at full operating RPM but I think the clutch is designed to accommodate for that since it has auto on/off option on my PTO (can turn on/off as I raise/lower the 3pt - a feature that I have yet to use!)... Definitely on me though for both the clutch adjustment and also will also own the blame for lack of circlip. I've seen that groove there plenty of times but just never thought "what's that there for?" since I never removed a circlip from it..

I wouldn't use that feature with a high inertia PTO implement such like a brush mower, flail mower, etc. The reason is that there is a spring actuated brake on the PTO once it's Off. So trying to constantly stop all that rotating mass on brush mower spinning at high RPMs is just unnecessary wear and tear not only on the brakes but also on the clutch discs when engaging again.

For low inertia implements like a rototiller, sure. It works great and I use that Auto feature all the time on my tractor.

This is just my opinion/theory by the way.

 

[mikester]

The gear box shaft on the OP's cutter has a groove for a circlip that is supposed to keep the PTO on the gear box even if the drive pin is sheared. That little circlip is pretty important to keep things like this from happening. I suggest you check your driveshaft to see if yours has that circlip or if it is missing.

As bad as this is, it could have been much worse. A new PTO plus all the other parts is going to be pretty expensive compared to the cost of that circlip.

The gear box shaft is smooth and uses a pin or bolt that is supposed to be the sacrificial part if the cutter hits something that is too much for the cutter. If they used a splined shaft, it would transfer the shock load to the tractor PTO and would be more expensive than replacing a simple shear pin or bolt.

Anyway.....look at your gear box shaft and you should see a retaining clip installed like this one. View attachment 750028

Unfortunately I have a splined shaft on both ends...

 

[5030]

I wouldn't use that feature with a high inertia PTO implement such like a brush mower, flail mower, etc. The reason is that there is a spring actuated brake on the PTO once it's Off. So trying to constantly stop all that rotating mass on brush mower spinning at high RPMs is just unnecessary wear and tear not only on the brakes but also on the clutch discs when engaging again.

Why I run a ratcheting over running coupler on my output stub so as to minimize the inertia rotation from the implement, in my case either mu bat wing mower or mu flat shredder. Both of them also have slip clutches and shear bolts (grade 2). Both are Land Pride units. When an inertia implement spins a disengaged pto, it eats up the pto internal brake. Most pto's aren't designed to provide excessive inertia braking. Once the internal brake is shot, the stub will rotate continuously from parasitic drive of the pto clutch.

 

[TexasDigger]

I wouldn't use that feature with a high inertia PTO implement such like a brush mower, flail mower, etc. The reason is that there is a spring actuated brake on the PTO once it's Off. So trying to constantly stop all that rotating mass on brush mower spinning at high RPMs is just unnecessary wear and tear not only on the brakes but also on the clutch discs when engaging again.

For low inertia implements like a rototiller, sure. It works great and I use that Auto feature all the time on my tractor.

This is just my opinion/theory by the way.

Tiller would be the only thing I could think the auto on/off feature would ever make sense for. Your comment on the extra wear on PTO brake reminds me that I need to also get an over-run clutch. That wouldn't have helped in this circumstance but would save excess wear on the backlash from rotating mass when turning off the PTO. Pretty sure that little 6ft RC on my tractor isn't as bad but will be upgrading to a larger RC in near future (I traded up for bigger tractor last year but kept the old 6ft RC & BB).

Speaking of the PTO, I did fire the tractor up last night and spun the PTO to inspect. Didn't see or hear any damage and the shaft seems to be spinning straight & true so counting my blessings for nothing other than a drive-shaft, a couple of retainer clips, some strap iron & chain and a little field welding! All in all, I'm at about $250-$300 total damage for not having a $1.49 circlip so will consider that as lucky!

 

[ericm979]

How do you get to the circlip with the clutch in place? The shaft sticking out of the clutch would block access to the circlip.

 

[TexasDigger]

How do you get to the circlip with the clutch in place? The shaft sticking out of the clutch would block access to the circlip.

I will find out on reassembly - I assume the first half of clutch has to be installed, then clip, then re-assemble/adjust clutch, but will confirm once I get it back together.

 

[ROUSTABOUT]

Oh yeah it did! It sounded like machine-gun fire... even my wife came outside to check - she said the banging was so loud when it spun loose that she thought I had rolled the tractor over!

Mine flew off 3 times cutting hay a few days ago. Cutting 100 acres tomorrow. Maybe it'll do better. I tightened the trip on it.

 

[Tinhack]

I will find out on reassembly - I assume the first half of clutch has to be installed, then clip, then re-assemble/adjust clutch, but will confirm once I get it back together.

Yes, the clutch must be disassembled and reassembled on the shaft to install the clip. I took mine apart to clean the disks and clutch plate since they looked paint covered. And, oh yeah, I remember measuring the force to compress the springs 1/4". I don't recall any of them being the same or even the same free height. Off-shore stuff for sure. So instead of counting turns, as the instructions say, I used a torque wrench to match pressure against the plate once I got past the initial locknut torque. I wish I could remember the final torque since it took me a few trial and error attempts for my ~47hp PTO. At the time, I had some pretty high grass and weeds with some <2" saplings--Mostly Mesquite. I kept matching torque on the bolts until it didn't slip on "MY STUFF". I could hear the pitch change.

Oh, and my cutter is a six footer. Cheap Country Line so I added the clutch. YMMV.

 

[TexasDigger]

Yes, the clutch must be disassembled and reassembled on the shaft to install the clip. I took mine apart to clean the disks and clutch plate since they looked paint covered. And, oh yeah, I remember measuring the force to compress the springs 1/4". I don't recall any of them being the same or even the same free height. Off-shore stuff for sure. So instead of counting turns, as the instructions say, I used a torque wrench to match pressure against the plate once I got past the initial locknut torque. I wish I could remember the final torque since it took me a few trial and error attempts for my ~47hp PTO. At the time, I had some pretty high grass and weeds with some <2" saplings--Mostly Mesquite. I kept matching torque on the bolts until it didn't slip on "MY STUFF". I could hear the pitch change.

Oh, and my cutter is a six footer. Cheap Country Line so I added the clutch. YMMV.

Didn't think about torquing each nut individually - that would make sense (like a drum head!). I think I'm at 63 hp on the PTO which is a LOT for what I'm pulling behind it - still using my little medium duty six footer that came with my previous rig. Had no choice but to go with a clutch that obviously isn't clutching! Will get it figured out but looking like it may be this weekend before I have a free day to tinker.

 

[Sawyer Rob]

I've said it before on this site, and I'll repeat it here.

You have to adjust the clutch for the hp of YOUR tractor, not to some spec. in a book! That book doesn't know what YOUR tractors hp is.

SR

 

[LouNY]

Well I've just been reading and not commenting on this thread till now.
That thru bolt holding the slip clutch to the shaft is NOT a shear bolt. Yes, it sheared it is not intended to be the shear bolt or safety.
Unless a manufacture specifys a grade 2, 5 or 8 "shear" bolt I always use a grade 5 or an 8, they will shear clean and the pieces will be easier to remove. Grade 2 or ungraded bolts are likely to smear when they break making them selves harder to remove the pieces.
If the hole in the shaft is not the same size as the slip clutch and a snug fit it will be getting hammered back and forth every power cycle and will fail eventually.
Also if the threads of the bolt are in the plane of the shearing force the strength will be greatly reduced.
Also over tightening a shear bolt will change it's shear strength.

In my opinion the slip clutch should be adjusted to protect the implement,
if I have 80 HP on an implement that is rated for 40 HP the clutch needs to give when more then 40 HP is applied or when an obstacle is struck which results in more then the recommended power to keep rotating..

 

[kwbobwi]

In case anyone takes life for granted when standing near a spinning PTO shaft - here's what can happen when a #8 grade bolt for PTO clutch is no match for PTO engagement at 2000 RPM's (that was my fault - had just turned PTO off and saw I had missed a spot so turned it right back on before before throttling down - clutch had already stopped all RPM's so when it re-engaged it hit HARD). This happened so fast that I didn't even have time to disengage PTO or kill the engine. Scared the living $#!#!#$ out of me and thank GOD I was out of harms way. Before I could even turn off key, shaft had already slung off the RC's gear-box, wildly flinging shrapnel into the abyss, slung around the strap metal holding weight for rear of RC, ripped the welded chain right in half and TWISTED THE ENTIRE STRAP FOR RC UP WITH PTO SHAFT!!! It instantly killed the engine from the shaft seizing due to being twisted up and can only hope no internal damage to engine/powertrain (sounded OK but will be keeping close eye on it). After further examination this morning, it also broke a U-joint and bent the U-join housing on yolk - was only a few revolutions away from slinging my clutch like a cannon-ball. Pics were taken this morning after I had already untwisted the PTO shaft and RC strap from one another - they were wrapped so tight that the best visual description I can come up with is that they were TWISTED AROUND EACH OTHER LIKE A BREAD TIE!!! They were twisted together so tight that I couldn't lower the 3 point down in order to to hook a chain to temporarily lift up the rear of mower long enough to get it back to house - had to un-twist them before I could move this mangled mess to further inspect the damage.

Lesson: Check all PTO u-joints & connections etc REGULARLY before operating. If you EVER suspect anything a-miss going on behind the back tires - ALWAYS disengage PTO. This could happen to anyone running a sheer-bolt style implement in a fraction of a second and if you get in the way of a spinning shaft or the debris flinging off of it while spinning at ANY RPM (In my case - 2000 rpm's = just <540), based on how quick it twisted up the 5/16-3/8? steel strap, it would be nothing for it to kill/severely mangle/dismember someone in its path. Scary stuff. Will always be more careful around PTO after seeing this & hope it helps anyone else that reads this to understand how serious that little scary sticker is about the PTO shaft's ability to cause physical harm/death. The little WARNING!/DANGER! sticker of the stick figure twisted up around PTO shaft is no joke - if you don't believe it, take a look at these pics & imagine that metal strap was your arm!

When I was on the farm, when ever we went to use a piece of equipment with a slip clutch we would loosened the clutch, engaged the pto to make sure it was slipping properly and then readjusted it, several times equipment that sat for a year or so the clutch would rust/seize together and be a pain to break loose.
The few extra minutes it takes to do that and check everything can save time and money down the road

 

[JWR]

Well I've just been reading and not commenting on this thread till now.
That thru bolt holding the slip clutch to the shaft is NOT a shear bolt. Yes, it sheared it is not intended to be the shear bolt or safety.
Unless a manufacture specifys a grade 2, 5 or 8 "shear" bolt I always use a grade 5 or an 8, they will shear clean and the pieces will be easier to remove. Grade 2 or ungraded bolts are likely to smear when they break making them selves harder to remove the pieces.
If the hole in the shaft is not the same size as the slip clutch and a snug fit it will be getting hammered back and forth every power cycle and will fail eventually.
Also if the threads of the bolt are in the plane of the shearing force the strength will be greatly reduced.
Also over tightening a shear bolt will change it's shear strength.

In my opinion the slip clutch should be adjusted to protect the implement,
if I have 80 HP on an implement that is rated for 40 HP the clutch needs to give when more then 40 HP is applied or when an obstacle is struck which results in more then the recommended power to keep rotating..

Amen Lou. I still am not clear on exactly how this catastrophe happened. So a bolt (which really should not have been viewed as a shear bolt) does shear and things go whirling on with inertia ... so what? How does that create all this damage? Among other things I am not a fan of mixing shear bolt protection with slip clutch protection. Splined shafts that do not slip go with slip clutches and controlled slip.

 

[Gord Baker]

Shouldn't there be a circlip that would prevent the shaft from coming off after the shear bolt broke?

I still don't understand how and why manufacturers insist on that design of shear pin with the smooth input shaft on the gearbox. Not only it makes it a mess to change the shear pin, it also makes it prone for this situation to happen.

Good thing there was no one around when that happened.

The shaft and bore have to be smooth for the Shear Pin to work.
The Grade 8, Grade 5 designations are for Tensile (pulling strength) NOT Shear strength. I don't know if there is a difference. What is RC? Remote Clutch?

 

[charles todd]

No circlip or anything to hold in place - at least not that I could find. You would think they would come up with some kind of design where a spring-clip or something holds onto a groove to keep from sliding/spinning off (similar to the way the 6-spline end works). Something for mfr's to consider for the next Gen sheer-pin style! Just saw that there is a 6-spline shear pin set-up but doesn't help for implements with the standard 1 3/8 shaft where the shear bolt goes right through the shaft.

My Rhino 172 is setup like that. Sheared many of grade 8, 1/2" bolts between the slip clutch and gearbox. It has a circlip, snap ring, something. It never did anything but spin on the shaft when bolt would break.

CT