Hayes master cylinder internal kit strokerinternal master cylinder parts all hfx mag compatible master cylinder internals are designed for the current aluminum piston2mm push rod platform 2003 and newer plastic piston2 5mm push rod parts are no longer available br4336 may be purchased to update 2000 2002 mag brakes all parts listed as el camino compatible will also function with ec trail brakes buy hayes components from chain reaction cycles the worlds largest online bike store