Just taken my standard dump valve apart and what i have found looks a bit like its incomplete to me.
I have the plate that the vacume hose connects to and behind that is an alu cylinder with a smaller bit inside which sits inside where the hole is (if that makes sense) this part is mounted in to a rubber sleeve.
Thats all there is, no spring and it appears no spacer unless the alu bit mentioned above is it.
Need help......am i missing something!!!???