[Latitude 28]

This is going to be long winded please bear with me on my thought.  Back in my corporate aircraft maintenance days.  We operated three Lear 45s that had Garret engines with the aircraft hydraulic pumps, constant pressure/variable displacement type of pump.  Variable displacement was achieved by a multi piston pump attached to a wobble plate that changed angles as the demand increased.  On the Lear 45s the hydraulic system had this high frequency buzz that would eat o-rings, tubing or anything that touched the tubing.  Needless to say a constant hydraulic issues with this model aircraft aircraft.   A few years later I was working on Cessna Citation Sevens.  Same basic engine model, same basic hydraulic pumps as the Lear 45.  Except the hyd system had one tiny, seemingly insignificant difference.....just a few inches from the pump was an device called an "acoustic ball' about the size of a tennis ball teed off of the pressure output line of the pump.  This stainless steel ball was nothing more than an passive dead space in the hydraulic pressure side of the system.  That device adsorbed the high frequency buzz in the Citation model of aircraft's hydraulic system.  Side note; we had zero issues with the Citation's hydraulic system.

Now having said that....I am thinking by adding a passive dead space as close to the pump as possible (on the pressure line).  It would absorb the pressure impulses from the hydraulic pump as well as the engine and or the PTO i.e. the Wanderlodge and Country Coach. 

This passive dead space needs to be on the high point of the pressure line close to the pump and could be nothing more than a capped tube tee'd into the pressure line. 

Disclosure: I am not a hydraulic engineer take the above based on end user experience living with what engineers designed.