If you have the metal valve stems, there is a rubber gasket that can leak if pushed a certain way. If the rubber has hardened, the gasket may leak at certain times and may seal fine at other times. You also may have the valve core that has corroded from moisture inside the tire.
..I'd be very surprised if a rubber gasket would harden, or a valve core had corroded, on a tire and valve stem thats only 3 years old?? Especially since we're talking about some very nice (expensive!) valve stems like the Borg dually valve stems.
Yes, its metal stems. As far as the rubber gasket leaking only when pushed a certain way: It is leaking when sitting parked in my driveway. At the tire shop, the guy grabbed end of the long valve stem, moved it all around. Was no evidence of leaking at the stem's base, where it goes into the rim (they had sprayed soap water all around there). That being the case, it seems unlikely the stem's rubber gasket is the culprit, but I guess it *might* be.
Tank it. Spraying it may catch the most obvious stuff.
..I wondered if there wasn't a way they could put the whole tire in a tank and do this. Think I'll ask around, see if I can find a shop that has the capability to do this with a tire this size. Thanks for the idea. :)
Did the tire shop air up the tire to max before soap testing?
Yes, they actually had it aired up above its max - max is 95 psi, they put 110 in it before doing their soap testing.
I'd go ahead and remove the borg stem and see if that fixes it.
I've thought of that, but I really don't want to. I really like these Borg valve stems, giving up on them and removing them will be a last resort. Everyone I've talked to, including many tire service professionals, swears that these valve stems are the best there is.
Anyway, thanks for the responses, suggestions, please keep them coming. Fortunately, we aren't heading out with the RV for some time (not until April), so I've got plenty of time to figure this out. :)
Will
