I have an old (~18 years) delta tub faucet - the up and down on/off and side to side hot/cold type. It delivers a very constricted flow of hot water. The sink in the room has plenty of hot water pressure. The cold water pressure is fine. I have replaced the springs and washers in the faucet. The valve has what appear to be integral shutoffs for each hot and cold water. I can't get these to turn. Where might I find product literature for this faucet and what might I do to get the integral valves to turn? Thanks.