Probably did it wrong.
I am in the process of changing out a vane pump on the NAA to a piston pump. I have the pipes that go with the piston style pump. I am wondering if I am using the correct "O-ring" in the grove of the pump. The kit I got had several sized round style o-rings and some square shoulder o-rings. Seemed to me that the o-ring that fit the best in the pump was the square shoulder style. I put it together last night but have not put the oil back in so I can take it back apart if needed. Whatcha guys think? Did I choose the wrong one for the pump. The square shoulder style that I put in the pump did not fully fill the machined groove. The rounded style in the kit seemed either too large or too small. If I put the oil in and get the tractor running, I can test it but then if it is not correct, I will have to drain it out again.