HYDRAULIC BRAKE MASTER CYLINDER WITH BACK-UP RING

摘要

Disclosed herein is a hydraulic master cylinder body having a bore defined at least in part by a bore wal l, wherein the bore wall includes an opening for hydraulic fluid to be passed into the bore, and a piston assembly situated at least substantially in the bore, the assembly having a piston with a piston body and at least one cup seal situated substantially around the piston body, the cup seal situated adjacent to the bore wail so as to be in sealing engagement therewith, and a back-up ring that is situated about the piston body, wherein the back-up ring is positioned to at least partially cover a portion of the cup sea! that is adjacent to the bore wail and to prevent at least a portion of the cup seal from contacting the bore wall and the opening for hydraulic fluid during piston actuation.