"Richard Smith" wrote in message ...

"Jim Wilkins" writes:

"Richard Smith" wrote in message
...

Hi all
(for "jack" cylinder connected by hose to hand-pump)
Dismantled cylinder with blown seal and got new seal on-order.
When I "mantle" the cylinder with the new seal in-place, I'd have to
ensure no air trapped in it? When ready for use?
I think it's infeasible to assemble the cylinder with oil in it. You
have to invert it to make some assembly (the return spring?) hang
centrally so you can push the piston in and catch the central "thing"
with its screw through the head of the piston. Plus then push piston
to bottom of travel.
Assemble piston with smear of oil left, piston to bottom of cylinder,
then pump oil in, disconnect, put cyl. on side with connector
uppermost, push on seal-on-disconnect ball in fitting and push piston
along cylinder expelling air? Until oil starts to emerge?
Shake and tap cylinder, back to same position of connector uppermost
and repeat "bleed" - see oil coming out free of bubbles?

Regards,
Rich S

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I just positioned the cylinder with its in/out port upwards and ran
the piston out and back a few times. You can tell if there's air left
by the solid or mushy feel of the pump handle when the piston reaches
full travel.

Does the pump have some mechanism to throw out air in the system?
Is it "self-bleeding"?

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Oil released from the cylinder to retract the piston flows back into the
pump's reservoir, which needs to be vented to the atmosphere to relieve
pressure or vacuum as oil moves in and out. I have a hand/foot powered
manual hydraulic pump with a hex head reservoir fill and bleeder screw that
the instructions say to slightly open during use.