I was having the same problem with a couple of my tire valves. A couple would stick open when checking the pressure. I would have to essentially work the valve several times by continuing to press the valve until it would pop back out and seal. These valves also had a slow leak. I would lose about 5 PSI a week from them. I purchased a box of double seal inflate through valve caps (Ebay item 200844119533) and have not had any issues since. Even if the schrader valve in the valve stem sticks open these caps act as a backup valve. I have not lost a single PSI from a tire since installing them. Very high quality German made product. $29 for 50 of them. I have put them on every schrader valve I have.
Thanks for the tip. I was having the same problem. Makes perfect sense to me your suggestion and it will be easier to check the air pressure. I ordered from the same source you suggested on ebay.
Thanks
I am thinking of getting a tire pressure monitoring system called TireMinder from minderresearch. Does anyone have any experience with them? If you get the entire system(about $400) you can put the sensors on the tow vehicle in addition to the RV.
Thanks