Braking
From GummyCarbs
Brake Caliper Pistons
When you squeeze the brake lever, hydraulic fluid is pushed from the master cylinder, though the brake hose, increasing pressure in the brake caliper. This pressure forces the brake piston outward, pushing the brake pad against the brake disc.
Because of their relatively inaccessible location and exposure to water, salt, and corrosive brake dust, brake caliper pistons are highly susceptible to corrosion.
Stainless Steel
The most common material for corrosion-resistant aftermarket caliper pistons is stainless steel.
Phenolic Plastic
Amazingly, phenolic plastic can apparently sustain the pressure and temperatures generated in braking systems!
- Vyncolit has produced phenolic brake pistons since the 1970s. Their [www.vyncolit.com/EN/6News/Piston%20V1_03.pdf brochure] describes the advantages.
- Sumitomo began production in early 2007.