I haven't used the shower in my second bathroom for a while and when I tried to use it the shower the diverted value wouldn't turn. I have taken value apart but cann't remove value body.(item that turns to divert water to shower)it is frozen its housing. I have been soaking value shaft with WD-40 for two days with no luck. Is there a way that I can free up the value with out having to replace the complete fixture.