mcfarmall
Veteran Member
- Joined
- Oct 1, 2015
- Messages
- 1,483
- Location
- Kalamazoo, MI
- Tractor
- Kubota M5660, Farmall C, JD 260 lawn tractor
Recently my brother in law toasted his old 6' brush cutter.
He did a little mowing job for the old lady across the street and "hit something pretty hard." After the collision he noticed that there was oil on top of the deck so he suspected the input shaft seal was leaking. He topped off the g-box with the recommended lubricant and proceeded to mow some more. He noticed a larger quantity of oil on the deck so he stopped to investigate and the gearbox was too hot to touch (>140F).
He decided at 30+ years old, the cutter had served him well and he went out and bought a new Woods 5 footer.
I performed an autopsy on the gearbox and driveline and here's what I found. The upper bearing had failed catastrophically, the cage came apart and got chewed up in the gear teeth damaging them beyond repair, then the balls got wedged in between the inner and outer races. 6 of them got worn in half and the other 4 became friction welded together on the outer race, then the outer race broke in two. The lower bearing cage was damaged as well as the bearing cap due to chunks of the upper bearing cage being ground up like a roller mill. The input bearings were intact but very noisy when spun by hand. The input bevel gear was severely worn but not as bad as the output gear.
The output shaft was also bent when I spun it up in the lathe.
The Walterscheid driveline was severely worn and galled on the thrust surfaces...it's the kind that's essentially round with 2 "ribs" that run lengthwise and a spinny plastic shield. The slip clutch was seized up due to never being loosened and spun like the mfgr recommends. The telescoping shaft had never been disassembled, cleaned and greased like the mfgr recommends either.
So in conclusion I have two "take aways" that should be considered going forward.
1. Disassemble, clean and lubricate the driveline as recommended by the mfgr.
2. Don't mow tall grass for the nice old lady across the street.
He did a little mowing job for the old lady across the street and "hit something pretty hard." After the collision he noticed that there was oil on top of the deck so he suspected the input shaft seal was leaking. He topped off the g-box with the recommended lubricant and proceeded to mow some more. He noticed a larger quantity of oil on the deck so he stopped to investigate and the gearbox was too hot to touch (>140F).
He decided at 30+ years old, the cutter had served him well and he went out and bought a new Woods 5 footer.
I performed an autopsy on the gearbox and driveline and here's what I found. The upper bearing had failed catastrophically, the cage came apart and got chewed up in the gear teeth damaging them beyond repair, then the balls got wedged in between the inner and outer races. 6 of them got worn in half and the other 4 became friction welded together on the outer race, then the outer race broke in two. The lower bearing cage was damaged as well as the bearing cap due to chunks of the upper bearing cage being ground up like a roller mill. The input bearings were intact but very noisy when spun by hand. The input bevel gear was severely worn but not as bad as the output gear.
The output shaft was also bent when I spun it up in the lathe.
The Walterscheid driveline was severely worn and galled on the thrust surfaces...it's the kind that's essentially round with 2 "ribs" that run lengthwise and a spinny plastic shield. The slip clutch was seized up due to never being loosened and spun like the mfgr recommends. The telescoping shaft had never been disassembled, cleaned and greased like the mfgr recommends either.
So in conclusion I have two "take aways" that should be considered going forward.
1. Disassemble, clean and lubricate the driveline as recommended by the mfgr.
2. Don't mow tall grass for the nice old lady across the street.
