Tire valve extension

[folivier]

I'm having a problem with the driver side inner rear tire. It has a valve stem extension and doesn't leak air. However when I attach a tire pressure sensor it loses air. I've switched sensors and determined the sensor is ok. What I'm thinking is the extension is not normally pressured but when the sensor is attached it is pressured and leaks at the connection to the valve stem (which I can't see).
Is there a certain type of extension that is designed to remain pressured up?
Thanks,
Forest

[fulltiming]

Forest, it could be the extension BUT if the tire pressure sensor is touching any part of the wheel, it may be the valve stem on the inner tire itself leaking. These tire use screw in valve stems. The valve stem is placed through the wheel, then a nut is put on the inside of the wheel and tightened to compress the rubber. As the rubber ages and/or the nut loosens from wiggling the valve stem, you can get a slow air leak around the valve stem.

I would check with a heavy truck tire shop to see if it is the valve stem or the extension that is leaking.

The other thing to check is to make sure the valve is securely seated in the stem. You can get a valve stem remover from an automotive parts place or even Wal-Mart. Make sure the valve stem is tight (clockwise to tighten).

[encantotom]

i have the same sensors on my wheels. though they are not heavy, they might be enough to bounce the valve stem around enough to cause it to leak if it was like michael describes.

I don't believe i have extensions on mine. when i had the new tires put on i had them put on valve stems that reach far enough.

tom