Technician A says that a steel piston should have a greater piston-to-caliper bore clearance than a phenolic piston because the steel piston will expand when the brake fluid temperature increases during normal braking. Technician B says that the phenolic piston should have the greater clearance. Which technician is correct?

Question

Quizplus · Accepted Answer

Technician B is correct because phenolic pistons, being made of a type of plastic, expand more than steel pistons when heated. Therefore, they require greater clearance to accommodate this expansion and prevent the piston from seizing in the caliper bore.

Technician a Says That a Steel Piston Should Have a Greater