air from cylinder on reassembly

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"?

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

----------------------------- 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.

Ah... The oil separates to the top in the pump's oil reservoir and can be expelled / displaced with additional oil...

Ah... The oil separates to the top in the pump's oil reservoir and can be expelled / displaced with additional oil...

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I just finished reading this book;

author is a racing engineer familiar with the technical difficulties of high horsepower engines which he describes in detail, such as the problem of separating the highly agitated oil and air froth that comes back from the scavenger pumps in the dry sump Merlin, so that air bubbles won't be pumped into highly loaded crankshaft bearings which would allow them to rub and wear rapidly. The problem is worse in a fighter where "down" can be in any direction.

... The problem [of liquids vs gravity] is worse in a fighter where "down" can be in any direction.

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One of my main heroes. Her story is how you learn technical things. Book "Negative Gravity". She spawned through her war work a generation of engineers who came of age in the 1960's. Apparently she was a demanding taskmaster. It was said that if things didn't work out, you'd better have a good account of yourself - but if you could, that was just experience for moving onwards (or something like that).

I like the strength of personality and identity in taking on the then ultimate machine (the Rolls-Royce Merlin engine), unfazed, and being its master.

One of my main heroes. Her story is how you learn technical things. Book "Negative Gravity". She spawned through her war work a generation of engineers who came of age in the 1960's. Apparently she was a demanding taskmaster. It was said that if things didn't work out, you'd better have a good account of yourself - but if you could, that was just experience for moving onwards (or something like that).

I like the strength of personality and identity in taking on the then ultimate machine (the Rolls-Royce Merlin engine), unfazed, and being its master.

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I'm impressed by Sir Stanley Hooker's contributions, despite his being "Not Much of an Engineer"

And Frank Whittle was credited for inventing the turbo jet (1930-37). ...

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He was -one- of the inventors.