I stepped on brake with rear brake line removed from proportioning block..and brass piston came out most the way . could not get it to go all the way back down in so I removed and cleaned the whole thing. it has 5 inlets/outlets..my question is ..did I put the piston back in the right direction? (will go in either way) ..and is the piston the only part in the hole ?..did I loose something in the dirt while traveling around in my driveway?