Hydraulic Leak Test

NON-PRESSURE LEAKS
An empty brake master cylinder reservoir condition may be caused by two types of non-pressure external leaks.
^ An external leak may occur at the brake master cylinder reservoir cap because of improper positioning of the gasket and cap. Reposition cap and gasket.
^ An external leak may occur at the brake master cylinder reservoir mounting grommets. Service such a leak by installing new grommets.

HYDRAULIC LEAK TEST
It is possible that all evidence of fluid leakage may have washed off if the vehicle has been operated in rain or snow, because brake fluid is water-soluble.
^ Refill brake master cylinder reservoir and bleed system.
^ Apply the brakes several times.
^ Examine the system to verify that the brake master cylinder reservoir fluid level is actually dropping.
^ Locate and correct the external leak.
^ If fluid level drops and no external leak can be found, perform the bore end seal leak test. Bore End Seal Leak Test