i dont know if this is the right or wrong way or even good advice for you since i put my old one in the trash and just installed a new one but i took a hammer and tapped on the POS Navi valve a while on all sides (as best as a i could get to) then took some large channel locks and pulled up on it. It came out after a while and was caked with crap. Just keep after it, on and make sure you take the two bolts out first.