Kubota manufactures tractors, mowers and light to medium-duty construction equipment. Several of their vehicles have moving parts, such as scoops or buckets. The driver operates these hydraulic components, but the actual movement and power is ultimately created by hydraulic cylinders. Kubota hydraulic cylinders operate like any other hydraulic cylinders. They have the same parts, so they can be rebuilt in the same way. To make the rebuilding process easier, reseal kits are available that contain every internal seal that needs to be replaced to rebuild a Kubota hydraulic cylinder.
Disassembly
Unscrew any caps or plugs from the cylinder's fluid ports and drain all the hydraulic fluid from the cylinder.
Clamp the cylinder in a bench vise and extend the piston rod fully. Unscrew the head, or gland from the rod end of the cylinder. You will probably need to use a gland wrench to do this.
Remove the piston rod from the rest of the cylinder by pulling it straight out of the barrel.
Clamp the piston rod in carefully in a vise. You should use a vise with soft jaws that won't damage the polished surface of the piston rod. Unscrew the nut holding the piston to the rest of the rod assembly, then slide the piston, the head and any other parts off of the cylinder rod
Remove all the seals from the piston, head and other parts with a seal removal tool. Then clean them with a safe, petroleum-based solvent, and inspect them for gouges and scratches. Replace any heavily damaged parts.
Assembly
Install new seals from the cylinder reseal kit on every component that was originally sealed.
Slide the gland, piston and any other applicable parts back onto the piston rod in their original configurations. Tighten the piston nut to its manufacturer-specified torque with a calibrated torque wrench.
Slide the piston rod assembly back into the cylinder barrel. Tighten the gland nut onto the cylinder barrel.
