Check Cause of Empty M/C Reservoir Without External Leak

An empty brake master cylinder reservoir condition may be caused by three types of non-pressure external leaks:

Type 1: An external leak may occur at the brake master cylinder filler cap because of improper positioning.

Type 2: An external leak may occur at the mounting end of the brake master cylinder because of a bore end seal leak. Service the brake master cylinder.

Type 3: An external leak may occur in the rubber hoses between the brake master cylinder reservoir and brake master cylinder. Check the rubber hoses for damage. Replace if necessary.