Kubota made two different kits for the cylinders on this loader. One kit has a seal on the bottom of the piston that is approx. 3/8 of an inch wide. The other kit does not have this seal. When I rebuilt the cylinders on mine, the dealer ordered the wrong kit the first time. When I went to pick up the kits, I noticed that the wide seal was not in the pkg. I pointed this out to them and, at first, they said that was the only kit made for that loader. Upon checking further, they found that there was, indeed, another kit. They ordered the kit and it had the proper seal. However, one of the "O" rings in the kit, (goes inside the piston itself) was too small. Went back to the dealer and got the correct part for the piston. Problem solved. If I can be of further assistance, feel free to contact me at email@example.com.