I was doing standard PM items on my wife's 08 Rubicon and went to add air to the tires (dash light had been on) and attached the filler hose, added air to just under 40, went to take the filler hose off and the end of the stem broke off. This happened on both rear tires. Both had low pressure. When I inspected the others, I found that they looked like they had been replaced recently, even the one on the spare. I brought it to the tire place and they put two new ones on. They asked me if I wanted the new ones to look like the original or was it OK to use the new rubber stems that were available. I had them put the rubber stems in thinking that they wouldn't fail like the plastic ones. If I don't like the way they look I'm going to paint them silver so they look more like the others. Anyway, all 5 have been replaced and most likely for the same reason....brittle plastic. Anybody else have brittle stems?