Reservoir quit holding fluid and determined fluid was leaking into hydraulics . Took axles off finding brakes were completely worn out . Starting ordering new parts and found out the 36530-65623 & 36530-65633 o-rings have been discontinued. Kubota does not offer interchangeable O-rings and cannot find aftermarket exact replacements. Trying now to have some custom O-rings made but do not know the tolerances of the brake case or the brake cylinder in order to get the correct fit . Does anyone have any experience with this or have any suggestions.? Also what is the best way to install cylinder into brake case without damaging o-ringa if I do find o-rings that will work?