That may or may not fit, it does look very similar to your old one.
Just as a watch out. I think the original valve may have been replaced. I expected your BF900 to be very similar to my BT900, but my valve doesn't look like your pictures, so I looked up the parts diagram on Messick's.
The diagram shows a sectional valve and yours is monoblock, the diagram shows a fork end on the spool and yours is a spade. And that 'assembly'
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
in your picture doesn't look like mine.
I'm just pointing this out that even OEM parts may not work on your machine. With luck, your valve is a Bailey and the actuator you found will work.
Heres a picture of mine with the cover off. I think yours originally was the same (less the third section).
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