Sheared PTO shaft again on Flail Mower

[DennisH]

Ok got the shaft apart last night and realized it broke in the same place it did last year. As you can see in the pictures the roll pin has worked itself out of the hole (same as last year). Question is did this cause the shaft to break or did the break push the roll pin out?

From the looks of the broken pin hole it appears the shaft is moving inside the coupler causing the pin to work itself out and the shaft to fail?????

I cut off the damage part last night, put it back together and moved 4 AC with no problems. Not sure if this is a Ser 3 or 4 PTO?

 

[RickB]

That telescoping shaft looks dry. That needs to be greased and slide freely or it will cause a failure similar to what you experienced. I'm going to guess it is a series 3, but it is only a guess.

 

[LD1]

Here is a good link to help you determine what size you currently have Agricultural PTOs

It appears as though yours is a Walterscheid style. You can click on the different sizes in that chart and they list the dimensions of the tubes and u-joints. See which one you have and make sure its big enough, otherwise, this is going to be an ongoing problem.

 

[DennisH]

It measured out to be a Size 4 Bondioli and Pavesi PTO Driveline. I will grease the shaft and see how that works out.

 

[JoeL4330]

not my field of expertise, but you cut off some few inches and are using it with success (so far), this might suggest it was too long then, or too short now.

 

[atgreene]

TSC stuff isn't known to be heavy duty. Go to a good driveline shop or a real tractor dealer and get yourself a heavy duty driveshaft.

I've twisted and broken numerous driveshafts, always due to trying to run one that was lighter than the machine requires. I've learned my lesson.

 

[aczlan]

Ok got the shaft apart last night and realized it broke in the same place it did last year. As you can see in the pictures the roll pin has worked itself out of the hole (same as last year). Question is did this cause the shaft to break or did the break push the roll pin out?
From the looks of the broken pin hole it appears the shaft is moving inside the coupler causing the pin to work itself out and the shaft to fail?????
I cut off the damage part last night, put it back together and moved 4 AC with no problems. Not sure if this is a Ser 3 or 4 PTO?

Looks like the rollpin is coming out and you are ripping the shaft up from all the force on one side of the shaft. I would get a long bolt that would fit inside the rollpin and put a washer on each end to keep the rollpin from coming out.

Aaron Z

 

[RickB]

Looks like the rollpin is coming out and you are ripping the shaft up from all the force on one side of the shaft. Aaron Z

All of which could be caused from the aforementioned lack of rease AND too much angularity on one or both of the u-joints.

 

[drs1023]

There always seems to be a trade off about beefier PTO shafts, replacing shear pins or belts, etc. Once I used up all my shear pins augering some 12" holes in solid red clay, so I "temporarily" put in a hardened bolt just to finish out the last hole. I twisted the end off the input shaft on the auger. Result - scrap iron!

On another occasion, I used a cheaper version of PTO shaft for a mower and promptly wrapped some D109 slick wire around the blades and snapped it into. So I made a new drive shaft out of some solid 2" square stock on the input end and 2 1/4" hollow square tubing on the receiving end. I found the next weakest link to be the "Made in India" ratchet clutch on the end of my PTO shaft. It got trashed a few weeks ago. I replaced it with the same type unit. I decided not to beef up with a stronger unit because the next weakest link might be the PTO shaft itself.