This depends what shut off valve is in question here. Where the leak is and what type of material is the shut off valve made of.
the hot water valve shut off valve shuts off the hot water. The cold water valve shuts off the cold water. ;()
What to use to solder a shut off valve
An air-intake engine shut-off valve regulates air-flow to the motor, and operates as an emergency shut-off valve. There are also shut-off valves on water hoses, so shut-off valves really control the inflow of any liquid or gas.
where is the fuel shut-off valve on a 1998 4 runner?
The shut off valve.
It doesn't need a shut off valve. In fact only Ford Motor Company installs fuel shut off valves in their cars.
With the vehicle aired up, push in the clutch, put the vehicle into gear, and turn off the ignition (leaving the tractor protection valve pushed in). When the motor is shut off, release the clutch. The motor will be off and the vehicle will be in gear, which will prevent you from rolling. Now, you simply pump on the brake pedal. This will reduce air pressure in the tanks (which won't build back up, as the motor is cut off). The tractor protection valve should pop out automatically when air pressure gets below 60.
shut off valve filters in tank stopped up or the valve is bad.
A gate valve is positive shut off and used for on of off . A globe valve is for throttling
The valve seat or washer on the main valve are not seating/sealing properly.
THERE IS A RELAY ON THE SHUT OFF AND SOMETIMES IT DOES NOT RESET AFTER THE KEY IS SHUT OFF .ORIGINALLY WHEN YOU TURNED YOUR TRACTOR OFF AND ENGINE STOPPED YOU WOULD HEAR A CLICK.THIS WAS THE SHUT OFF RELAY RESETTING