pump will come on at 30psi , but won't shut down at 50 psi of 55 psi or 60 psi?
adjustments , not change, replaced the switch , drained tank as instructed , 0 psi at switch gage but also 0 or little at tank ? Recharged tank to 28 psi , then turned on water supply , gets to 50 psi and stays there , but pump still running?
turned off manually , then checked tank psi = 40psi ? Should this not stay at 28 psi , where is the water going ? Into the tank?, buddy thinks the bladder has gone bad, in the tank 23years old..?

thanks
m

I think your gauge might be defective. The pressure at the top of the tank should be about the same as the gauge once the system is up and running. The 28# will increase once the system pressure gets up. It will only be 28 when the system is off and drained.

When you check the pressure and get 40 at the top of the tank, your gauge should also be reading about 40.

The fact that the bladder pressure was zero when you drained the system is a little alarming. It should have stayed up, but even a blown bladder would not prevent the switch from cutting off. Be sure the gauge is accurate, and then be sure nothing is blocking the pipe leading to the switch.