I have a new to me 2006 Newmar Dutch Star 4028 that seems to roll a little when I dump the air in the suspension. If I'm parked on site with a slight incline and I am about to put the jacks down it will roll forward an inch or 2 when I dump the air bags. I'm assuming there is either a partially plugged vent or a check valve between the parking brake circuit and the rear bags vent but I'm having a hard time finding a complete diagram of the whole air system. The parking brake does hold well even on pretty steep inclines any other time. It just acts like it is getting fed some of the vent air from dumping the bags.
Any help/advise would be greatly appreciated!