We have 5 x739 tractors with 60" rotary brooms. Since Winter of 2014 we have broken the shaft that runs between the gearbox and the chain about 5 times on different brooms. Some multiple times. The shaft will break right at the drive sprocket. It looks like it just twists right off. I called my dealer and they have not heard of any such thing. The other dealer near me said that the local school has the same broom and went through 3 shafts over the same 2014 winter.
These shafts are a PITA to repair. I cannot for the life of me press the shaft out of the gearbox which means I have to also replace the gearbox as well as the shaft and misc. parts. This is getting to be a regular thing and it isn't fun to have to do in a time crunch. It has gotten to the point that the local dealer stocks the parts to repair these, which is why I am surprised there isn't a TAC case.
I thought maybe it was because they were engaging the PTO with the engine at full speed but my dealer said that shouldn't matter. Also when the other shafts broke I noticed the chains were super dry and some links were seized so I figured they were binding but this recent break the chain was nice and free.
Also, Hi, I'm Travis, the grounds mechanic for the State of Michigan.