I recently rebuilt the vane type hydraulic pump on my D6B. I was able to find a service manual for the hydraulic system on ebay and it saved me from making a mistake that would have destroyed my pump! This pump is designed for both clockwise and counterclockwise rotation and can be assembled either way. If assembled for the rotation opposite of the one needed the pump won't lubricate. I don't know if this applies to other model vane pumps but it might so that is the reason for this post.
The pages attached are for the Denison pump used on the D6B.
Craig