Need some help with a Speakman Diverter valve. This valve I would assume has been in the house since 1956 and is no longer able to divert the water to either the shower or faucet. Water flows through both no matter which way the level is turned. Basically how do I take this apart. Talking to a store clerk he said there was a bolt that needed to be unscrewed via a shower socket and it should come apart. Is there one universal size or are they all different.