On Oct 28, 1:53*pm, db_sonic wrote:
I had a failed jack that I took apart to see why it was not
maintaining the extended position. In my case the ramp would slowly
lower back to collapsed postition, which besides annoying, can be a
danger to the fuselage. *Turns out that it was the synthetic plunger
on the main piston leaking. *So even under pressure the oil would seep
past the plunger and the piston slowly looses position till it
eventually collapses. *The culprit does not seem to be any of the
various ball-bearings in the base of the jack.

Anybody know if a replacement plunger could be obtained. *I am sure
its much cheaper than a new jack.

Unscrew (remove) the bleed down screw dig out the old oring replace
with a new one. Worked for me.