It's a very simple job, really. I'm sure you know all of the bleeding procedures, this has been discussed many times. But on the Perkins, making sure the timing is correct is paramount. Lining up the gear will be included clearly in the manual, but one trick I always do is, mark the pump mounting on the block. When it is bolted on loosely, you can see where it will pivot slightly back and forth, and that is the minute timing feature of the fuel. Just like a distributor on a gas burner, it makes a difference in the fuel timing. When you reset the pump back to its original camber, it will be very, very close to being where it should be, as the old one was in that position as well.
Scribe a hard line on the pump across the block where it rests. If you're just rebuilding the old pump, the scribe line will still be there, and it's a whiz-bang.
And a side note, I hope you're just rebuilding the old one. Unless the pump is just worn to a FRAZZLE, most can be rebuilt. And a lot cheaper. These things will run several thousand hours without just wearing one out.
