[snj8198]

sry i didnt see this thread sooner. I too am running serp system based on the mid '90's truck system. The reman pumps as Truckdude stated are really hit and miss and not worth monkeying with for the limited savings.

Piston and spring can be very finicky. The slightest debris will block the flow passage around the piston resulting in no assist. Don't forget that while all these pumps look almost the same, they are different as they have a different relief spring pressure, pin length, and the orifice flow diameter. Then there are pump differences between vehicles with vacuum assist and hydro boost. I spent a week researching, fiddling, and blowing up pumps before I figured out a combo that worked for my set up. I finally settled with a p-pump from a 2005 diesel and made some modifications. I documented everything and now i can find my file. If I lose my pump i'll swap my piston assembly and orifice to a new pump.