I just changed mine because it was leaking from back side where the e brake is. I found one form a 400ex and it fit perfect, but the new one had an aftermarket e brake eliminator block off plug. I bet that is all I needed in the first place. If that is where yours is leaking from you just need to buy that $12 part and eliminate the e brake like I did. Or I still got my old one if you need that.