ON CERTAIN TRAILERS EQUIPPED WITH SEALCO SPRING BRAKE CONTROL VALVE ASSEMBLIES INCORPORATED IN ARVINMERITOR AXLES, PART NOS. 110700 AND 110800, THERE IS A RECESSED AREA ON TOP OF THE VALVE IN WHICH A BRASS GUIDE PIN FITS DOWN INSIDE THE BODY OF THE VALVE AND IS HELD IN PLACE BY A STEEL SNAP RING. THE RECESSED AREA ALLOWS ACCUMULATION OF WATER, DIRT, AND/OR CHEMICALS TO BUILD UP BEHIND THE SNAP RING TO THE POINT WHERE IT WILL NO LONGER CONTAIN THE GUIDE PIN RESULTING IN A FAILURE OF THE AIR VALVE.