[fhhhstix]

As you retract the cylinder the rod takes up space and not as much fluid is needed to move the piston as what is needed to extend the cylinder. The level of the fluid in the tank will go up and down with these actions. You should have some air space in the tank when the excavator is in the ready position (boom up with the stick strait up and down). In this position the cylinders should be close to half stroke. As RCP57 said the breather should be open so the tank doesn't build up pressure or vacuum (what it does) which will cause the pump to labor or the tank to collapse or explode if it is not open (the purpose).


Travis