Just did my air pump too and SAS valve. I replaced mine because I understood that the valve can become carboned up and corroded and usually contributes to the pump going. I noticed that when I tried to blow through the valve once it was off, some air was getting through...though not much. This didn't happen on the new valve...it was airtight. If you take the valve off, you can use carb cleaner to get come of the carbon out, but since most replace the valve when the pump it done, you might want to do it given the expense of the pump.

db