My shower the pipes vibrate when hot water is turned on and water pressure goes way down what would cause this to happen ?

A loose or broken washer would cause the problem you describe. What's the brand name of the valve? One handled or two knobs? How old? Back to you. Tom

A loose or broken washer would cause the problem you describe. What's the brand name of the valve? One handled or two knobs? How old? Back to you. Tom
Thank you Tom that was what it was a broken washer on the diverter valve anyway thanks again Joe