Backhoe BH90 Stiff Valve

[TORQUIN]

The dipper out direction on my BH90 gets stiff very quickly. By stiff I mean that when a push the lever it moves very lowly and the lever doesn't move much. If I put some force into it and push it all the way, the dipper moves quickly and suddenly the out direction frees up and works smoothly. If it don't use it for a minute or so, it stiffens up again and I have to push the control lever hard to get it to go to the end of expected travel. No problems with the in direction or any of the other directional controls of the back hoe. One of the out riggers is exhibiting a similar problem when going up. I have to really push it hard to get the the control lever to move as far as it should, and to get the outrigger to come up fast.

Has anyone else encountered this behavior, and fixed it? If so, I'd like to know what you did to diagnose and fix it.

Thanks,
Chris