bearcat flail chopper

[Finnbair2020]

I have a bearcat 6 foot flail chopper. I seem to be going through a lot of shear bolts at the flywheel/clutch that is next to the gearbox. I'm not sure why-- sometimes it's running fine and when I turn off the PTO, it snaps a shearbolt-- sometimes one breaks when I start out. They are quite a pain to put in-- the two parts of the flywheel are very difficult to match up properly. I'm tempted to get a stronger bolt...
 

[Dick2]

If you are using a common Grade 2 bolt, you could try a Grade 5 bolt before you put in a Grade 8 bolt. It might help if you slow down the chopper as slow as you can before disengaging the clutch. It appears that the momentum of the chopper may be creating a backlash on the shear bolt.
 

[BushogPapa]

I believe I would be looking either at the Gearbox or under it for signs of anything striking under the mower..
It shouldn't be shearing the pins..

Does your tractor have a strong PTO Brake that might cause this..?

Ron..
 

[karl f]

if it"s a 72a like we had, I seem to recall it had an over-running clutch on the gearbox input, which should alleviate shut down driveline stresses. Also the gearbox has a bunch of shims under it to align it perfectly to the blower shaft--if the blower has been adjusted (if it is adjustable) you may need to re align the gear box. There is a double roller-chain coupler for some flex, but I seem to recall the gearbox had to be aligned fairly square to the blower shaft anyway. No matter what tractor, we idled them way low and then engaged the PTO and brought the machine up to speed. The one time we didn"t, the gearbox became shrapnel, even with the slip clutch and shearbolt for protection. Make sure there aren"t any bearings out and the shafts spin true. the shearbolt flanges may need to come apart and be cleaned and inspected to make sure they move freely to seat squarely together.

good luck
karl f
 

[jon f mn]

Also check the bolt holes for wear. My baler is a problem too, but I can see that the bolt holes vave a gouge in them from using too soft bolts. I will need to build it up again for next year.