The question is: Why isn’t there a paper gasket between the Transfer Plate and the Lift Cover on the F40? Is it related to the hydraulic pressure and the O-ring under the plate? In an early correspondence when you were instructing me on the rebuild of the brakes of my early “20” you pointed out that metal to metal contacts were completed with paper gaskets. I assumed this was a general principle applicable to all metal to metal contacts.
The O-ring, or in this case, 2 O-rings serve as the gasket for the transfer plate. There is an O -ring in the groove at the end of the stand pipe and another in the recessed area of the transfer plate. O-rings hold better, do not squeeze out or blow out, when high pressures are involved. They are superior to paper gaskets in these applications. Ferguson began replacing paper gaskets with O -rings in the hydraulic system beginning with the TO-30. The paper gaskets on the TO-20 hydraulic pump side-chambers and the lift cylinder were replaced with O-rings on the TO-30. The hydraulic system on the TO-35 and subsequent models make extensive use of O-rings.