... three cylinders of each pump are interchangeable. Valve-over-valve (through type cylinder)design reduces the cylinder ... are interchangeable. F-500 mud pump uses API#5 valve pot, F-800 and F-1000 mud ... pumps use API#6 valve pots. Bi-metal liners are used. The ... : Cylinders, liners, pistons, valves, valve seats, valve springs, seal rings, valve covers and cylinder covers at the fluid ...