Bought a pontoon with this brake actuator (?). After I finally got the fill cap off as it had corroded into place, the resevior had about 1/8" of water in it, totally rusted inside. That's the MC right? Do you think it's rebuildable? I know this is not much to go on, just looking for opinions. The trailer is a '95 model Tracker dual axle for a 24' pontoon boat.