Many times a leaking schrader valve can be fixed by either simply tightening the valve core, or replacing the core.
To tighten the core you will need a valve core tool available at any tire or auto parts store. 
To replace the core, you will need a new schrader valve core, again available from auto parts and tire stores 
If you have further questions please contact us at 888-925-4621 M-F from 7 to 4 PT or here