I gotta think that the first thing to do is to take the leaky wheel to another tire shop. Maybe tell the second shop that another shop could not find the leak, but you knew they could because you'd heard that they were the real experts!
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch