Vortech MP40 question

[cyberdude47]

I just bought an mp40w and haven't received it yet but am told after purchasing that it needs a new pin spacer due to it starting to make noise. Now I know nothing about these pumps and from my reading the spacer looks like "we'll a spacer" that just clips on to the dry side. Now my question is how would this piece cause noise and how should it wear out as I cannot see any moving parts that mate to this piece and don't understand how it can wear out???