Will hydraulic ram self bleed

[Justme]

Will a single acting hydraulic ram self bleed?

I just cant see how they can unless the air can get past the seals & the oil cant. The oil inlet is at the bottom & the ram raises so the air would be trapped at the top.

 

[wyn]

If it's single acting the neck seals probably allow the air out from the top of the ram. The initial air on the oil side will probably disapear after a couple of cycles of the ram.

 

[rtbcomp]

Can you not arrange it so the connection is at the highest point in order to bleed it and then fix it in its operating position?

 

[Justme]

Yes thats an option, I was just hoping not to have to do it.

 

[morph]

The unpressurised side should have vents in but the oil side won't matter. 3000psi of oil removes air instantly!! So yes they do self bleed.

 

[Paul.]

Usually they self bleed when they've been cycled a few times, make sure there is plenty of oil in the tank so that when the air is displaced the pump won't cavitate, bleeding from a fitting is a messy business.

 

[pedrobedro]

Is it in a jack or engine hoist type situation ? Fill it up and then replace the screw you use to release the pressure but don't screw it in tight enough to seal. Now pump the handle a few times and you will hear the air escape. If it's in a circulating system the oil carries the air back to the tank when the ram compresses.

 

[Bsmith]

You have a point but it will certainly self bleed.....

 

[Justme]

Thanks all.

Its powered via a tractor so the "tank" holds over 50L so filling one ram wont be a problem lol.

Just need to get the right quick fit fitting so I can test it.