Air in loader system

[flyingace43]

On my Case ih compact tractor I seem to have gotten air into the loader and bucket cylinders. The cylinders have slop in them and I can move the bucket 4" by hand. Causes problems when I back drag to level of material.
What's the best way to bleed out the air without a big mess? I think it might have ran low on fluid one time after I purchased a new backhoe. I bad I know.

Had a case 45C and it did the same thing so I would raise the loader all the way up then cycle the bucket a few times and it would be ok until the next time I used it. Fixed by trading it in on a Yanmar YT347 and no longer have any problems now.

 

[RandyT]

The biggest issue with most of the compact tractors is the pump cannot produce enough volume to keep up with refilling the cyinder as the cylinders move under heavy loads when lowering or dumping the bucket. This causes a vacuum to form in the gravity side of the cylinder leading to cavitation of the fluid. This creates a low pressure issue and basically boils the fluid creating air pockets that then have to be purged to get the rigid hydraulic feel back Normally more common with dumping the bucket then raising or lowering the arms, but produces that floppy issue.

Restrictor valves are suppost to help prevent this and in some cases does, but are not totally effective especially for somebody that doesn't run at full throttle when using the loader.

 

[D&D]

On my Case ih compact tractor I seem to have gotten air into the loader and bucket cylinders. The cylinders have slop in them and I can move the bucket 4" by hand. Causes problems when I back drag to level of material.
What's the best way to bleed out the air without a big mess? I think it might have ran low on fluid one time after I purchased a new backhoe. I bad I know.

If you’ve cycled the cylinder(s) 6, 10, 12 times (w/e , pick a number) air is being introduced somewhere. Check tightness on all the hydraulic fittings and every o-ring seal (orfs, orb, q/d) becomes suspect. As an example,

https://www.hydraulicsdirect.com/_next/image?url=https%3A%2F%2Fapi.hydraulicsdirect.com%2Fimages%2Fdetailed%2F27%2FSS-6801-08-08_TopView_Rect.jpg&w=3840&q=75

 

[WinterDeere]

This creates a low pressure issue and basically boils the fluid creating air pockets that then have to be purged to get the rigid hydraulic feel back

Wow... I learned something, here! I can understand how this would happen, but not being a chemist, I'm wondering how the bubbles would persist once that side of the system regains pressure. No air is introduced, the bubbles would be at low pressure, and I would think they should disappear every bit as quickly as they appeared, immediately upon the restoration of pressure.

 

[RandyT]

Wow... I learned something, here! I can understand how this would happen, but not being a chemist, I'm wondering how the bubbles would persist once that side of the system regains pressure. No air is introduced, the bubbles would be at low pressure, and I would think they should disappear every bit as quickly as they appeared, immediately upon the restoration of pressure.

They do, but the second side of this is the side of the cylinder that was under vacuum becomes an open return to tank when the cylinder is actuated. So unless special valves are used, one side of the cylinder is always under system pressure and the other side is low pressure or neutral.

 

[zrtext]

If you’ve cycled the cylinder(s) 6, 10, 12 times (w/e , pick a number) air is being introduced somewhere. Check tightness on all the hydraulic fittings and every o-ring seal (orfs, orb, q/d) becomes suspect. As an example,

https://www.hydraulicsdirect.com/_next/image?url=https%3A%2F%2Fapi.hydraulicsdirect.com%2Fimages%2Fdetailed%2F27%2FSS-6801-08-08_TopView_Rect.jpg&w=3840&q=75

thank you as i will check into the fittings and hoses for issues

 

[zrtext]

They do, but the second side of this is the side of the cylinder that was under vacuum becomes an open return to tank when the cylinder is actuated. So unless special valves are used, one side of the cylinder is always under system pressure and the other side is low pressure or neutral.

yes I'm well aware of the of that, thank you

 

[D&D]

thank you as i will check into the fittings and hoses for issues

Being a bit of a Debbie downer now. I’d start with the suspected cylinders and valves. Unfortunately, it could be on any part of the tractor. Last one I had, it was under the seat on the 3 point fittings