Posted for "Bill&Sue" <5zq@cox.net>:

 Hi Doug,
 
 Sounds to me like the accumulator has lost it's air pre-load. The accumulator
should contain both air (compressible) and hydraulic fluid (non-compressible).
As hydraulic pressure builds it moves into the accumulator and compresses the
air. As hydraulic pressure decreases, the compressed air forces the hydraulic
pressure back out. If fluid has leaked into the air side, or if air has leaked
out, there would be less gas to compress and you would see the symptoms that
you describe.
 
 Bill Harrelson
 N5ZQ 320 1,200 hrs
 N6ZQ  IV  8.003%