Brush hog driveshaft snapped in 1/2!
- Thread starter denverdave66
- Start date
OP
denverdave66
Silver Member
I just replaced it with a new bolt be sure and use the same size bolt and not buy one that is harder. I rather bust a $2 bolt than a $$$ driveshaft.
Bolt?
I have a easy attachment device. I dropped the bushhog and pulled away without disconnecting the driveshaft from the PTO. It pulled the shaft in two. Is it possible to hammer the shaft back in or will I need a more sophisticated, expensive fix?
I have a easy attachment device. I dropped the bushhog and pulled away without disconnecting the driveshaft from the PTO. It pulled the shaft in two. Is it possible to hammer the shaft back in or will I need a more sophisticated, expensive fix?
k0ua
Epic Contributor
Rothebob, when the "bolt" was referred to, what is mean is the "shearbolt" on the connection point of the gearbox on the rotary cutter (bushhog). There are two kinds of safety devices on the rotary cutters to prevent damage to the PTO shaft itself or its internals. There is a device called a "slipclutch" that is a spring loadec clutch assembly that will allow slippage if the rotary cutter blades hang up on something. It is adjustable, and needs maintenance (see manual if you have one). and there is the shearbolt. On the shearbolt arrangement the input shaft to the rotary cutter gearbox is a smooth round piece of metal stock without splines. It does have a hole drilled thru it and the corresponding yoke or collar on the PTO shaft slides over this smooth round shaft and you must align the predrilled holes and place a 1/2 inch shearbolt (a low quality bolt, usually a grade 2 common bolt) thru these holes to prevent the rotation of the yoke on the smooth shaft. When the blades encounter an immovable object (big stump or rock) the shear bolt does just that it shears off and relieves the strain on the PTO and drive line. Think of it as a fuse for electricity. You replace the bolt with the same low grade bolt and go on mowing a little wiser than when you started
As you have seen a PTO driveline shaft consist of 2 pieces that slide together (with lubricating grease, be sure to lube at least every mowing season) This allows the shaft to telescope together and further apart as you move your 3pt hitch up and down the length usually increases as you lower the mower and decreases as you raise your mower. It is common to have a minimum of 1/3 of the shaft length in engagement at all times. But on the other hand you do not ever want the possibility of the shaft being so long as in any circumstance to put pressure on the tractors PTO shaft and bearing area when it is raised and shortened like for instance when backing up a very steep incline and the rotary cutter raising beyond the point the 3pth hitch would raise it. This can damage the PTO shaft and bearings.James K0UA