BD brake is built for maximum performance, durability, and years of trouble-free use. They tell us they've never had a brake seize up, thanks to the their proprietary design. The brake has to be able to withstand the extreme heat particulates of diesel exhaust day in and day out for the life of truck. This is a challenge when the parts must be metal-on-metal, moving parts.
The brake housing is cast from high silicone ductile iron. But all moving parts are stainless steel in order to resist corrosion and provide long life. One of BD's secrets is the is their AlumiBronze bushing that gets inserted into the cast iron housing. The stainless steel butterfly valve shaft pivots in the bushing. The bushing and shaft are sealed with small piston rings to keep particulates out of the bushing.