Rotary Cutter Bush hog pto shaft problem

[gbates]

I have a problem with twisting the pto shaft on my bush hog. I have to be honest, I'm new to farming. I grew up using tractors but they were older models. I recently bought a used Kioti dk55. It has an electric pto, which I'm not used to. The first time I used a bush hog with it I was thinking and turned on the pto with the rpm's too high. It was as if i had hit something and when I pushed in the clutch it didn't stop the pto. (this was what I was used to). Before I could push the button, the u-joint broke and it twisted the inner part of the shaft. Got that fixed and lesson learned. I have been careful not to engage the pto except at lowest rpm. However, I keep shearing bolts and the shaft has again twist to the point I can't seperate the 2 piece shaft. The blades and gear box turn freely. Any ideas?

 

[rd_macgregor]

I have a problem with twisting the pto shaft on my bush hog. I have to be honest, I'm new to farming. I grew up using tractors but they were older models. I recently bought a used Kioti dk55. It has an electric pto, which I'm not used to. The first time I used a bush hog with it I was thinking and turned on the pto with the rpm's too high. It was as if i had hit something and when I pushed in the clutch it didn't stop the pto. (this was what I was used to). Before I could push the button, the u-joint broke and it twisted the inner part of the shaft. Got that fixed and lesson learned. I have been careful not to engage the pto except at lowest rpm. However, I keep shearing bolts and the shaft has again twist to the point I can't seperate the 2 piece shaft. The blades and gear box turn freely. Any ideas?

My mower (behind an '06 DK45SC) has a slip clutch, so I may be a bit better protected than you. Still, I would expect a shear bolt to break long before the PTO shaft twists. I, too, try to remember to engage the mower before ramping up the rpms. Sometimes I forget and engage at 2k+ rpm, but haven't yet managed to damage anything. When you engaged the PTO, was the mower sitting on the ground in such a way that the blades couldn't turn easily?

 

[newbury]

What class is your PTO shaft? If it's a class 4 you may have to many HP for your shaft.

 

[SPYDERLK]

What class is your PTO shaft? If it's a class 4 you may have to many HP for your shaft.

This has to be it. ... and combined with too strong a shear bolt for the shaft assembly. Perhaps OP bought the bushog used and a different [light duty] drive assembly had been put on it.
larry

 

[newbury]

I suggested that because I bought my rotary cutter used and it came with a Class 4 which I just broke a cross bearing on and bent the yoke with my M4700.

 

[Hilbilly]

What kind of shear bolts are you using? If they are typical store bought grade 5 bolts they are too strong. I had a similar issue with my brush hog. My dealer didn't have the proper shear bolts, so I made some up using 1/2" hot rolled steel rod. It is no where near as strong as grade 5 bolts. I shear a lot more pins now, but am glad it's not the gear box or shaft that gets damaged.

 

[SPYDERLK]

What kind of shear bolts are you using? If they are typical store bought grade 5 bolts they are too strong. I had a similar issue with my brush hog. My dealer didn't have the proper shear bolts, so I made some up using 1/2" hot rolled steel rod. It is no where near as strong as grade 5 bolts. I shear a lot more pins now, but am glad it's not the gear box or shaft that gets damaged.

Yeah, but its more than that. The whole shaft assembly is too weak to run than hog to do whatever hes doing. We need some info on the hog duty and trans health and shearbolt size as well as when the failures are happening. :confused2: