I'd lose the spacer. Our IH 300 had some gaskets added that held the orings off and stopped them seating. Cleaned the faces and put hyd back together without and no leaks now.
On my mf 35 stop the oil too go back too the resovare, its there a valve in that hole or ., Must have some with the return of oil too, i open up the cover , an the return oil flowing out over cover
I have fitted a hydraulic selector valve and oil is leaking by the the side. The valve doesn't close on the top of the hydraulic cover , maybe 1 mm space.
