Pneumatic retract fill valve
Mine is a slow leak. If that valve is leaking, it takes about 5 minutes to be out of air. If not, I can go an hour and not lose air. Its just an intermittent problem. I have B&D retracts which dont have an O ring. I took it apart and its just a piece of rubber inside a sealed chamber that stops the airflow. The tire idea sounds good...but also sounds like ALOT of work.