I have my master cylinder and proportioning valve out right now to be refinished. I was going to powdercoat them both. If I pull the end bleeders off of the prop valve and remove the springs and pistons there are no other rubber pieces inside right? The reason I ask is I don't want to destroy it baking it at 450* to cure the powder. Thanks.

 

Well I gave it a try....I didn't see anything that looked like it would have rubber or plastic left in it. I'll find out later this week when I reinstall.