Originally Posted by layback40

I am surprised that some one hasnt come up with the suggestion of just doing away with the "rare valve" and replacing it with a basic adjustable pressure relief valve. They are use in all sorts of applications & normally adjustment is just by a small locking screw. There is one on the diesel return of an old Leyland diesel we have in a road grader. If it wasnt so cold & wet outside I would go take a pic of it !!