Bleeding lines on new grapple install

[wdchyd]

Hydraulic cylinders have seals that are oil tight not air tight.........

???.....:confused3:

 

[/pine]

???.....:confused3:

Actually I don't think it (air) needs to get down to molecular in size to pass by a seal (that holds oil)...
Air can be compressed and doing so makes it (air(bubbles)) much smaller...

...most hydraulic cylinders will work with air the same as fluid under a NO-load scenario...

 

[Wa11banger]

Wdchyd, yessir we have many filters in our lives that separate differing liquids due to their molecule size. Now filters are not seals but I would assume the same principle applies to all things with a specific tolerance.

 

[wdchyd]

Wdchyd, yessir we have many filters in our lives that separate differing liquids due to their molecule size. Now filters are not seals but I would assume the same principle applies to all things with a specific tolerance.

Then why are hyd cylinders and air cylinders manufactured with the same kind of seal materials (buna, polyurethane, Teflon).......we are talking tractor hydraulics right?......or space shuttles

 

[aczlan]

Then why are hyd cylinders and air cylinders manufactured with the same kind of seal materials (buna, polyurethane, Teflon).......we are talking tractor hydraulics right?......or space shuttles

Air cylinders don't generally see 2000-3000 PSI, Parker lists 250PSI as the max pressure for their air cylinders: http://www.parker.com/literature/Industrial Cylinder/cylinder/cat/english/0106c002.pdf.

Aaron Z

 

[J_J]

Hyd cyl should be both liquid and air tight.

If not, then we would be bleeding a lot of air.

If a hyd cyl was not air tight, we could just push all the air out through the seals.

If you can push air past the seals of a cyl, the you can also push fluid out.

 

[Wa11banger]

Actually I work for NASA so I kinda was talking space shuttles! But in all seriousness I see your point. The scale of tolerance in our tractor hydraulics may not be to the exacting tolerances required in the aerospace industry.

JJ it is feasible that air can leak past our seals more easily than hydro fluid as these are not perfect seals. Matter of fact a little oil leaks out of the cylinder every time it is cycled. Just at the microscopic level

 

[wdchyd]

Actually I work for NASA so I kinda was talking space shuttles! But in all seriousness I see your point. The scale of tolerance in our tractor hydraulics may not be to the exacting tolerances required in the aerospace industry.

I figured that anyone from Huntsville works there

 

[Little Tractor Ferndale]

I installed a anbo grapple on my TC30 also a WR Long 3 function Aux. valve and did not bleed in any other way then running the circuit in one direction. The air in fact does bypass all on its own!

 

[Mike476]

Todays hyd systems that are self bleeding have check valves in the system that allow air to breathe out, usually in the actuating cylinders themselves. Aircraft hydraulic systems do the same; they also maintain a pressure in the header tank to ensure positive flow.

Hyd fluids are chosen because of their compression ratios and resistance to foaming, it is essential that air be bled from a system to prevent that from happening.

While the system will bleed itself I would probably look to loop the new lines as well, if for no other reason than to make sure I maintain a good level of fluid in the system.