O-rings for plate assembly, hyd lift sump cover

richard d hayes · Jan 29, 2015

I have removed the "plate assembly" from the bottom of the hydraulic/transmission housing on my 841 ford in order to access the system/pump relief valve. Attached to the plate assembly is a small metal stud measuring 1/2 inch in diameter by 11/32 high with an O-ring. The stud does not show up on any drawings in the parts book nor any picture in the service manual or FO-20. The parts manual does show an O-ring, NCA-786-A, as one for "cover plate to center housing". Can someone tell me if this is the correct O-ring on the stud? Also, when I removed the cover plate there was no O-ring between the plate and bottom of the system/pump relief valve. Only a gasket. The bottom of the valve had made two impressions on the plate assembly (concentric circles) indicating metal on metal. My next question; is there suppose to be an O-ring between the plate and relief valve? If so, what is the O-ring number?

JMOR · Jan 29, 2015

(quoted from post at 13:27:33 01/29/15) I have removed the "plate assembly" from the bottom of the hydraulic/transmission housing on my 841 ford in order to access the system/pump relief valve. Attached to the plate assembly is a small metal stud measuring 1/2 inch in diameter by 11/32 high with an O-ring. The stud does not show up on any drawings in the parts book nor any picture in the service manual or FO-20. The parts manual does show an O-ring, NCA-786-A, as one for "cover plate to center housing". Can someone tell me if this is the correct O-ring on the stud? Also, when I removed the cover plate there was no O-ring between the plate and bottom of the system/pump relief valve. Only a gasket. The bottom of the valve had made two impressions on the plate assembly (concentric circles) indicating metal on metal. My next question; is there suppose to be an O-ring between the plate and relief valve? If so, what is the O-ring number?

o-20 shows an O-ring. Might find number on New Holland parts web site, or just take valve to any auto parts house & match one.

Dean · Jan 30, 2015

The O ring is available from CNH where you will need to order the gasket in any event. DO NOT use silicone on the plate.

The relief valve seals within its bore with O rings. IIRC, there is no O ring between the relief valve and gasket.

Do yourself a very big favor and do not use an aftermarket relief valve.

Dean

richard d hayes · Jan 31, 2015

Dean, JMOR
Thanks for your reply's. I did contact New Holland as suggested and got some information. The salesman also told me there did not appear to be an O-ring between the bottom of the relief valve and the plate. Thanks for your assistance and information.

JMOR · Jan 31, 2015

(quoted from post at 10:44:08 01/31/15) Dean, JMOR
Thanks for your reply's. I did contact New Holland as suggested and got some information. The salesman also told me there did not appear to be an O-ring between the bottom of the relief valve and the plate. Thanks for your assistance and information.

ell...........if I just had to take a stab at it, I would say that the "NH salesman" doesn't know how to read his own catalogs!

O-rings for plate assembly, hyd lift sump cover

richard d hayes

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JMOR

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Dean

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richard d hayes

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JMOR

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