I turned my water shut off valve for 10 days and then I turned it back on to find the shut off valve vibrating very badly after I flush, so I turned it off and replace the fluid master and turned it on to find it doing the same thing. The question I have is that I never turned it open all the way because I was scared it might blow, should I open the shut off valve all the way to stop the hammering?

Never mind turned it all the way on and it fixed its self :D

Yes open the shutoff valve all the way and see what happens, good luck.

John