Guys,

I've got 750 hrs on my 360 and rebuild a cylinder (1 of 6) or more every annual.  I was thinking this pump chirp discussion through and am considering installing an accumulator.  

My reasoning is as follows.  I believe that the total of 6 cylinders have a combined leak affect that is not reducable to zero.  Rebuild all 6 cylinders, replace the valve and two cylinders.  You name it, there is still some minor amount of fluid always getting around those O rings.  We mask this reality based on the following.

When we first fill our hyd systems there is air in them.  Try as I did to purge the system,  I think that some air remains initially.  This air is acting as an internal accumulator.  As up hyd pressure reaches 1200psi, the air volume is compressing.  As the slow leak through one or more seals drains fluid and resultant pressure, the air expands maintaining system pressure.  Thus, when we first rebuild a cylinder and add a little air to the system, we fly along fat dumb and happy that we've "solved" the problem when in reality we just recharged our accumulator (air in system).

However, over the course of many gear cycles, air tends to work it's way back to the resevoir resulting in less accumulator affect (and less air friction and damage to the seals).  This reveals itself as more frequent pump chirps.  The operator therefore assumes he has "developed a leak" when in reality the system total leak has not changed.

Parker Hannifan has a great read on picking an accumulator:
 
http://www.parker.com/ACCUMULATOR/CAT/ENGLISH/MAKINGCHOICES.PDF

I'd appreciate a sanity check before I buy.  What say you Scott, Chris, Mike, et al?

Larry
N360LH
750 hrs
Need to rebuild another hyd cyl.