TPMS puzzlement, problem.

[Want a B]

2009 Born Free, Built For Two on a F-350 dually chassis. EezTire TPMS with non-flow through sensors.

The TPMS I installed on my pickup truck and utility trailer two years ago. Worked with no problems. Sold the truck a month ago and bought the Born Free. Installed the TPMS on the Born Free.

Outside rear passenger side tire went flat in a few days. I figured I hadn't tighten the sensor enough so I refilled the tire to 65 PSI and put the sensor on nice and tight. Tire went flat again.

Refilled the tire with air, replaced the rubber gasket on the sensor. Tire went flat.

Perhaps the tire picked up a nail when I was driving the Born Free home. Aired the tire back up and left the TP sensor off. Week later the tire is still at 65 PSI.

Swapped sensors with the inside rear passenger side tire. The same outside rear passenger tire went flat again. Inside rear passenger tire remained at 65 PSI. This rules out the sensor as the problem.

No visible defects on the valve stem. Bought a tool to cleanup the valve stem's threads. Replaced the valve stem core with new. Air up tire and ... within a few days the tire is flat again.

The only thing it could possibly be (I think) is that the end of the valve stem isn't "square" which wouldn't allow it to seat flat against the sensor gasket?

I emailed the TPMS manufacturer. Received a reply to call their Tech support. Before I call and find out I'm missed something very obvious I thought I'd post my problem here.

What am I missing?

[markopolo]

I think you've figured it out. Something is not right with that stem above the core threads. It might be crack or perforation or the top edge as you mentioned.