Also, it is not the shear bolt that has the clip on it -- it is the shaft itself. The one that"clips" not "clamps". I misspoke. Sorry ! Got rattled !
I think the pto shaft is too long and its bottoming out when the back end of the attachment lifts, shearing the soft bolt. The harder bolt is strong enough to actually force the back of the tractor up. This is a dangerous situation because in the right circumstances it could tip the tractor over. It also puts high forces into the system, potentially breaking parts. Need to cut the pto shaft shorter - very important. (And go back to a soft bolt.)..........The bolt I have is only used to hold the shaft onto the PTO. If there is no bolt there then the shaft would come undone from the PTO and would start hitting everything. It happened many times before I put the grade 5 bolt in.....
........The bolt in pics is the "soft" bolt, it sheared not even 5 mins after trying it out again. I did not hit ANYTHING hard at all. It sheared just from the regular movement of the PTO. Something just isn't right with this.....
rbargeron- Thank you for the helpful advice. I was wondering if that was my problem or not. I didn't know how to come to a conclusion on that though. When I bought this setup, which came together, there was NO bolt or anything on the tractor/shaft connection. The splines went together and there is/was a "lever" type deal that I would move over to bring the two together and then the lever would move back and it would keep the shaft/tractor connection together. That lever is no longer holding it together. There was a "notch" cut out on the tractor's pto that the lever would fit inside and that would keep the pieces from coming apart. That didn't last all that long before the shaft come off of the tractor's pto and started banging around. That's when I figured I needed a bolt to hold it together.I think the pto shaft is too long and its bottoming out when the back end of the attachment lifts, shearing the soft bolt. The harder bolt is strong enough to actually force the back of the tractor up. This is a dangerous situation because in the right circumstances it could tip the tractor over. It also puts high forces into the system, potentially breaking parts. Need to cut the pto shaft shorter - very important. (And go back to a soft bolt.)
The telescoping pto shaft has to get longer and shorter as the tractor and mower move along uneven ground. Both ends need to be retained so the splines stay engaged. But if the shaft is too long it can't compress enough and something has to give.rbargeron- Thank you for the helpful advice. I was wondering if that was my problem or not. I didn't know how to come to a conclusion on that though.......
Russell King - That was a great breakdown and it explained everything exactly how it should be AND exactly how it is. Thank you, sir.Ok you are getting good information but confusion at the same time.
Starting at the tractor the PTO output is splined and has a groove in it near the tractor. The groove is fairly wide and like a half circle.
That end of the PTO shaft will have a mechanism to engage that groove. Sometimes it is a pin that is pushed in. Others have a twist or pull ring with ball bearings that engage the groove. From what yours looks like it is the pin type and there may be some bolt there instead of a pin.
At the mower gearbox the shaft pointing to the tractor is smooth and round. It has a narrow groove near the end closest to the tractor. The PTO shaft is also smooth bored and has a hole drilled crosswise to the bore. Slide the PTO shaft on to the mower shaft and it can be pushed far back so the groove is exposed. A circlip is installed into the groove and now the shaft is unable to come off the mower shaft. Now a bolt has to be installed through the holes in the PTO shaft and the mower shaft. This bolt is the shear bolt and transmits the tractor's output torque into the mower's input shaft. This is the bolt I was previously describing. I install a nut and a lock nut on this bolt so it is locked and can not come out. I do not tighten the first nut very much since it is not needed to be tight. There is no clip involved with the bolt. If this bolt is sheared the circlip in the end of the mower shaft will keep the PTO shaft from coming off.
I think you have a bolt at the tractor end instead of a pin and may be confused that is a shear bolt. It is not a shear pin or bolt. It retains the shaft onto the tractor PTO output shaft. I would not feel safe with anything there except the correct pin.
Please also get a safety shield onto the PTO SHAFT. In fact you may want to invest in a complete new PTO shaft between the tractor and mower.
I suggest you go to a tractor store and have them show you how the shaft is supposed to be installed at both ends.
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BigTrees: In the picture in post #17 it looks like the mower's stub shaft has splines. Does it? Or is it smooth? Also the pto shaft must be free to extend and compress a couple inches in operation. Blocking its motion is not a good idea - pvc would crush before causing an upset but stronger material would make it dangerous (see post #27)............At the mower gearbox the shaft pointing to the tractor is smooth and round.........
Thanks for that tip. I did leave a few inches for the expansion for when the lift raises and lowers but I could never get the length of pvc "just right" to keep it from falling off. The shaft coming off of the mower does NOT have splines, neither does that end of the shaft itself. On the tractor side, BOTH have splines.BigTrees: In the picture in post #17 it looks like the mower's stub shaft has splines. Does it? Or is it smooth? Also the pto shaft must be free to extend and compress a couple inches in operation. Blocking its motion is not a good idea - pvc would crush before causing an upset but stronger material would make it dangerous (see post #27).
Thanks for that, D2Cat, I was not aware of that.When you go to the tractor store, or contact the Bush Hog dealer, and just get the pin and spring that is not functioning correctly....don't need to by the complete end of the shaft.
I have banged away with a B7200 (17HP) and a 5" Mohawk cutter for 30 years with exactly the same result. Feeding stuff too big or too fast simply stalls the tractor and nothing breaks. The tractor doesn't even generate enough power to snap the shear pin designed to protect a 50HP gearbox.this is my experience as to the original question. I now run a six foot bushog on a mx5100 Kubota. Before that on a ford 641 48 hp with a five footer. Before that I used the five foot hog on a ford 9n that had about 20 hp. I ran this 9n five foot combo 30 years fro 1976 until 2006. The 9n was underpowered for heavier stuff but I banged away anyway. Never had the power to snap the shear bolt but stalled the tractor many times . I always wondered how that little tractor could take so much abuse. After 30 years of this abuse I sold it to a neighbour in 2006 and bought the 641 which could snap shear bolts. The neighbour still has it and it runs just fine!
My take away is maybe tractors are tougher than we think. Or maybe I was just lucky.