WE HAVE A 2001 REXHALL ANTHEM DIESEL PUSHER, WHILE DRIVING DOWN A MOUNTAIN IN YELLOWSTONE NATIONAL PARK IN 2004 OUR BRAKES FAILED AND WE HAD TO RUN INTO THE WOODS TO STOP. WE WERE TOWED OUT OF THE PARK, THE NEXT DAY WE HAD THE BRAKES CHECKED AND NOTHING WAS FOUND. SINCE THAT TIME IT HAS HAPPENED ATLEAST A DOZEN TIMES, BUT ONLY WHEN WE GO OUT WEST. WE HAVE CONTACTED REXHALL WHO REFERRED US TO SPARTAN. WE HAVE TAKEN IT TO SPARTAN RECOMMENDED SHOPS BUT NO ONE CAN FIND THE PROBLEM. THIS PAST YEAR WE PUT A HIGHER GRADE BRAKE FLUID IN BUT THAT DIDN'T HELP. OUR BRAKE SYSTEM IS AIR OVER HYDRAULICS, NO EMERGENCY BRAKE AND A PARKING BRAKE THAT WILL NOT HOLD IF IT IS ENGAGED WHILE MOVING. WE HAVE DONE ALL WE KNOW TO DO AND NEITHER COMPANY HAS ANY ANSWERS. THEY SAY THAT UNLESS IT HAPPENS WHEN A SERVICE TECH. TRIES IT THAT THEY DON'T KNOW WHAT IT IS. WE HAVE ALSO ADDED HEAVY DUTY BRAKE PADS AND KEEP ALL OF THIS CHECKED. WE NEVER RIDE THE BRAKES BUT TRY TO GEAR DOWN, BUT WHENEVER YOU PUT THE ALLISON TRANSMISSION IN 1ST OR 2ND GEAR IT DOESN'T HOLD, IT BUILDS UP SPEED AND SHIFTS TO THE NEXT GEAR WHILE GOING DOWN THE MOUNTAIN. ALSO, WE HAVE CONSTANT PROBLEMS WITH THE RADIATOR CLOGGING UP FROM DUST, WHICH CAUSES THE BUS TO RUN HOT. THE FIRST TIME THIS HAPPENED, NOT LONG AFTER WE HAD IT, WE HAD TO HAVE THE RADIATOR CUT OUT BECAUSE IT WAS WELDED IN. REXHALL DENIED THAT THEY HAD ANYTHING TO DO WITH THIS. THE RADIATOR IS LOCATED AT THE VERY BACK - BEHIND THE ENGINE (WHICH CREATES AI