OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Trimmers and Brushcutters Two Stroke Trimmers & Brushcutters Kubota D210 gear head maintenance

There is an oil seal on your machine, and it looks as if it runs on the outside of a sleeve that is not fitted in your picture. (The seal has a black rubber lip that seems to be rather chewed up.) The sleeve that fits inside the seal lip may be part of a fitting the cutter mounts on.

If you remove the three hex-plus-Phillips-head screws that are holding that pressed steel cover/retainer plate on, the retainer plate should lift off and most likely the oil seal and its mounting will lift off as well. Then you'll be able to see what holds the ball race in. Since there is an oil seal further down the shaft than the bearing, I doubt the ball race is supposed to be the sealed type. My current guess would be that they have used a separate oil seal and an open ball race so that the seal will be easy to replace, without having to pull out the output shaft and ball race to do it. It should just be a few minutes work, depending on how/whether the oil seal can be removed from the metal shell around it. If that is how it works, the oil seal is deliberately a throw-away item. It looks to me as if the gear head is supposed to be filled with oil. As soon as you see oil around the output shaft and cutter disk, you are supposed to replace the seal then refill with oil. That would be somewhat similar to the way some of the big tractor-mounted slasher gearboxes work. Whatever you do, people will get things wrapped around the shaft, and that will ruin the oil seal or the side-plate of a sealed bearing. The simplest solution is to make it easy for the operator to see that this has happened, and make the seal fairly easy to replace. Of course if the machine continues to be operated without oil, or with dirt inside the gearhead, all four bearings plus the pair of bevel gears will be ruined very quickly.

At the moment it looks as if the main mystery is in the missing cutter-mounting fitting, which is supposed to run inside the oil seal, and keep the dirt out. Is the missing sleeve that shiny metal tube just below the gear head in your picture? Or has somebody removed the original cutter mounting and fitted some aftermarket item at some point along the way? That might explain everything that has gone wrong since.