TRACTOR SLUNG PTO SHAFT!!! - PICS.

[blee03]

Holyyyyyy.... that'll wake ya up!

 

[TexasDigger]

Holyyyyyy.... that'll wake ya up!

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!

 

[mikester]

Thanks for posting.

I'm always weary that my chinesium 8" wood chipping with 200 lb flywheel may suddenly self destruct when I'm standing near it. I was hoping my newly added PTO clutch can help save me and the tractor from future damage...guess not!

 

[beowulf]

Thanks for posting. When it involves safety there can never be enough reminders.

 

[WM75Guy]

I would be replacing the tractor seat as well.

 

[5030]

Shear bolts should be a Grade 2, not aa 5..

 

[Jchonline]

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!

Your machine lets you keep the PTO engaged when you are out of the seat? Is it older or did you disable?

Mine I have to put in neutral, lift seat off of safety switch, then engage the PTO.

 

[2manyrocks]

Thanks for posting.

I'm always weary that my chinesium 8" wood chipping with 200 lb flywheel may suddenly self destruct when I'm standing near it. I was hoping my newly added PTO clutch can help save me and the tractor from future damage...guess not!

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.

 

[TexasDigger]

Shear bolts should be a Grade 2, not aa 5..

I have several Grade 2 bolts left from my inventory of going through them like candy which is what lead to me adding the clutch to RC. No more shear bolt on mine since adding the clutch. Allegedly, the bolt that came with the clutch to bolt it to RC gear-box shaft was Grade 8.. Either way, it still snapped. After re-adjusting the clutch (AND adding the new 1 1/4" C-clips that I just picked up earlier today!) I may go back to the Grade 2 if I feel safe enough about the C-clips keeping everything on there - if not, will end up with same problem!

 

[TexasDigger]

Your machine lets you keep the PTO engaged when you are out of the seat? Is it older or did you disable?

Mine I have to put in neutral, lift seat off of safety switch, then engage the PTO.

It's a 2021 model - no mods to any safety features. Stays engaged even when out of the seat as long as it's in neutral with parking brake on (I assume for running things like backhoe, log-splitters, generators, etc. off of the PTO.)