Standard hydraulic brakes use pistons, limiting size/weight. Additionally the pistons/bores/seal housing must be manufactured to high tolerance impacting ease/cost of production. The PCB makes the seal the piston, using a rolling diaphragm made from Viton with a Bakelite shield for heat capability. This means packaging space/weight/cost are all reduced. The diaphragm ensures positive pad removal and doesnt corrode so no sticky pistons. PCB has external fluid transfer improving heat dissipation aiding cooling of the brake oil. The lever housing and piston are made from plastic reducing weight/machining/cost and manufacturing carbon foot print.
