Calling for help! Trying to find why air keeps entering my hydraulics.

[dsebens]

I keep having air enter my dump side of the bucket hydraulics. This fitting is a swivel fitting and is loose when no pressure, it is the same on both sides. I thought maybe it was the spool orings in the valve as there was seeping there but I replaced them and thats no longer an issue. Can these types of fittings leak air into it when they are not under pressure? I have never seen any fluid come out of them. I have replaced the lower ones as the rubber was breaking off the hose but havent replaced these. Also if this could be the fault, these are not resealable right? I assume I can put new orings in?

I verified it is an air issue as when I take off the hose there is an air gap in the hose and top of cylinder. It causes the bucket to kind of float when lowering onto the ground, I have to "preload" it down then go back up once it engages the pile otherwise it will try to pull it down. You can also tell it is an air issue as I can stall the hydraulics instantly when maxed out the other way but dropping the bucket has to compress an air spring before it stalls the hydraulics.

 

[oldnslo]

Sounds like the typical floppy bucket syndrome experienced on some models of tractors and loaders. What is happening is that the load causes the dump cylinders to extend faster than the oil supply can fill the blind end of the cylinders. This creates a vacuum - air pocket in the blind end of the cylinders. One cure is to put a flow restriction on the rod end line for dump cylinders so you get a more positive power dump. Another is a valve that has regenerative dump feature. This directs the flow exiting the rod end back into the blind end. Gives you faster dump speed with minimal chance for floppy bucket.

My loader has single dump cylinder so I installed a counterbalance or over center valve. This allows smooth consistent dumping at all speeds since it requires a positive pressure in the blind end for the valve to open allowing it to extend. Very helpful when using forks and trying to feather the tilt.

Hopefully this all makes sense.

 

[dsebens]

Sounds like the typical floppy bucket syndrome experienced on some models of tractors and loaders. What is happening is that the load causes the dump cylinders to extend faster than the oil supply can fill the blind end of the cylinders. This creates a vacuum - air pocket in the blind end of the cylinders. One cure is to put a flow restriction on the rod end line for dump cylinders so you get a more positive power dump. Another is a valve that has regenerative dump feature. This directs the flow exiting the rod end back into the blind end. Gives you faster dump speed with minimal chance for floppy bucket.

My loader has single dump cylinder so I installed a counterbalance or over center valve. This allows smooth consistent dumping at all speeds since it requires a positive pressure in the blind end for the valve to open allowing it to extend. Very helpful when using forks and trying to feather the tilt.

Hopefully this all makes sense.

That does make sense which is why I think if I fix any air leaks I think it would be better? The loader valves are kind of a high gpm but I don’t want to replace it if I don’t have to. This valve doesn’t have a float either. I would love to have that but not if I don’t have to replace it.

 

[oldnslo]

That does make sense which is why I think if I fix any air leaks I think it would be better? The loader valves are kind of a high gpm but I don’t want to replace it if I don’t have to. This valve doesn’t have a float either. I would love to have that but not if I don’t have to replace it.

I doubt that you have an air leak causing this problem and there are no seals in the directional valve that would leak and allow air into the dump circuit. The only seals onna directional valve are on the ends of the spool preventing the tank line oil from leaking out. A system air leak would most likely affect all of the other functions.

An oversize valve might make the floppy bucket worse since will pass even more flow and allow bucket to dump even faster creating a bigger vacuum.

As a simple experiment try feathering the dump so it dumps slowly and see if still have the problem of air pocket. If no this is similar to restriction in rod end controlling how fast the bucket can dump.