(i) Field of the Invention
This invention relates to a waterproof seal ring to be fitted between the contacting surfaces of a master cylinder body and a power booster housing.
(ii) Description of the Prior Art
Conventional waterproof seal rings of this character have a recess formed at the lower end of the outer periphery, through which air is allowed to flow into and out of the master cylinder as its piston reciprocates. When rainwater or the like gains entrance between the contacting surfaces of the master cylinder body and the power boosting housing, it will flow down around the outer periphery of the seal ring. The intruding liquid can then be entrained by air that is drawn by suction into the master cylinder, eventually to corrode its inner wall surface. This is particularly true with the arrangements in which the master cylinders are installed with their axes increasingly raised frontwards, for example, to meet the recent design requirements of the braking systems for the front-engine front-wheel-drive automobiles.