Drive tore in half

[Surewhynot]

My first use of an old cutter. Three point connected fine, chains were tight and the PTO attached fine...made two swaths and then the drive shaft tore in half? WTH? I know I can get a new drive shaft, but why? PTO speed was around 11 to 12. It was an older KingKutter and looked to be in good shape, and I greased it before use and the gearbox was full. Never had that happen before. Any thoughts?

 

[Farmwithjunk]

My first use of an old cutter. Three point connected fine, chains were tight and the PTO attached fine...made two swaths and then the drive shaft tore in half? WTH? I know I can get a new drive shaft, but why? PTO speed was around 11 to 12. It was an older KingKutter and looked to be in good shape, and I greased it before use and the gearbox was full. Never had that happen before. Any thoughts?

Define (or post picture(s)) "tore in half". Did a u-joint fail? Did the center section of the shaft itself fail? Broken yoke? How long had it been sitting idle?

 

[Baby Grand]

I got a lotta diagnostics questions:

If your PTO shaft has a clutch, did you loosen the bolts and slip it before retorqueing and cutting? If it's a shear bolt, what grade bolt and what does it look like now? What were you cutting - grass, saplings, stumps?

 

[Ford850]

Until we see pics or have a better description it will be a guessing game. Here's my guess: Shaft was too short and over extended for the tractor, shear pin or slip clutch didn't release and the shaft twisted in two where it barely overlapped.

 

[Bird]

Shaft was too short and over extended

When he said "tore in half" that was my first thought; too short therefore not enough overlap in the middle.

 

[Surewhynot]

I wll buy too short a drive shaft. No damage to anything, just broke right in the middle of the shaft into two equal halfs. Guess it is off to TSC for a new shaft. This learn as you go stuff is expensive

 

[Surewhynot]

And thanks for the inputs, that was my guess as this was used on an old 8n before. I moved it as far in as the 3pt would allow, guess just not enough.

 

[Ford850]

And thanks for the inputs, that was my guess as this was used on an old 8n before. I moved it as far in as the 3pt would allow, guess just not enough.

Did it break in half, or just over extend and come apart into the 2 equal halves per design?

 

[Surewhynot]

It would appear that it seperated, but the plastic guard casing ripped in two. As it was pointed out...too short of a drive shaft. I will get a larger one at Tractor Supply when I get the chance. I see they carry three different sizes.

 

[Ductape]

I believe you can buy a PTO extension much cheaper than a whole new shaft...... just leave the extension on that shaft if you won't need it for any other impliments.

 

[zzvyb6]

Have you checked to see if the prop shaft hits the end of the drawbar (perhaps from raising or lowering the mower too much) and that contact is what's bending the shaft and tearing the shields?

 

[Bentwrench]

zzby6........Good point I have to leave the drawbar out of my utility tractor when using the bush-hog. When I drop over a steep bank or ditch my PTO shaft did get into the drawbar.

 

[AndyMA]

PTO speed was around 11 to 12.?

What does this mean? Is this the engine RPM's as measured on your tach? How does this compare to the 540 PTO speed that is probably recommended for your cutter?

Some machines spun at lower RPM's are actually under more stress.

Andy

 

[Surewhynot]

I didn't even think about the drawbar hitting the plastic guard I would imagine that is indeed what happened and that would explain the guard damage. And the seperation would be from lifting the cutter. I will check it out. On the bright side we are looking at 110+ heat index for the next three days and I am helping a freind bale hay