Brake Problem

[mcnitt]

I have a Grand L 3430 with about 460 hours on it. It's an eight speed gear drive, runs great, and does pretty much everything I want it to do. One problem though. The left rear wheel keeps locking up after I have either just braked or release the parking brake lever. I looked at the linkage, which appears to be moving as it should. It looks like whatever controls the brakes are internal - but is there something further I can do to check them? Or is a visit from my local dealer's service department in my near future?