I own a OMC aux. outboard bracket for my trolling motor. It operates with a air cylinder that aids in the raising and lowering of the motor. The air cylinder no longer works and I'm being told a new cylinder costs $159.95 and the existing one can't be repaired. Is this true or can this one be rebuilt? There is a small inlet that looks as though it can be recharged. Can I replace the seals and have this one recharged? The OMC PN# for the cylinder is 173721 and the bracket is rated for 125 lbs.