JD 570 B rotary manifold leaking hyd oil

I've got a John Deere 570 B grader that's been sitting in storage for a couple of years. I'm getting it ready for work but ran into a hydraulic oil seepage problem on the Rotary Manifold. We swapped out the gasket and that fixed it temporarily, but after the machine runs for about 5 minutes, the top plate starts leaking again. It looks like pressure is building up inside the manifold. What could I be overlooking here?

Did you swap out the seals #6?

No, I haven't. Is that something you see often on these John Deere machines?

This happens pretty often with rotary manifolds built that way. Item #6 seals stop oil from leaking between the ports internally, and the top and bottom seals also keep oil from leaking out on the outside.

I appreciate the help. I'll pick up the seals first thing Monday and give it a try. Thanks again.

We installed new seals in the manifold and that fixed the leak. Thanks for the help.