You probably have the original solenoids in that box (aluminum plate with platic cover). Be careful as the plate is not thick and the solenoids are mounted to it with only a few threads. I have pulled these solenoids apart to find the seals on the spools to be falling apart. This prevents them from moving correctly and thus functioning/sealing correctly. It seems that way back then the British rubber did not like American lubricants. You may want to take a look.