Brake retarder valve

A brake retarder valve for a tractor-trailer combination with a fluid line sequentially supplying pressurized fluid to a trailer axle brake and a tractor axle brake, said brake retarder valve being associated with said tractor axle brake, said brake retarder valve comprising:

• an housing defining a valve chamber having an open end and a closed end, said housing defining a housing fluid inlet and at least one housing fluid outlet, said at least one housing fluid outlet being orthogonal to said housing fluid inlet end;
• a valve seat defined in said housing within said valve assembly;
• and
• a valve assembly biased against said valve seat in an operative closed configuration to selectively restrict flow passage from housing fluid inlet to at least one housing fluid outlet, said valve assembly being selectively operable between said operative closed configuration and an open configuration for flow of fluid between the fluid line and said tractor axle brake, said valve assembly being selectively operable in response to a resultant of the fluid pressure between the trailer axle brake and a tractor axle brake,
• wherein an orifice is formed between associated members of said valve assembly in said operative closed configuration.