Abstract: A brake fluid tester for measuring the quality of brake fluid, comprising means for measuring the conductivity of the brake fluid, preferably comprising a plurality of comparators for comparing the resistance of the brake fluid to a plurality of reference, resistances. The device further comprises indicating means, preferably light emitting diodes, responsive to the measuring means for indicating the quality of the brake fluid based upon its measured conductivity. An increasing number of diodes are illuminated as the conductivity of the brake fluid increases, providing a positive indication when the device is working and providing an easy to interpret display of the test results. The diodes are preferably activated at preselected levels of conductivity, corresponding to preselected levels of moisture contamination.

Abstract: This invention relates to a portable combustion leak tester for water-cooled internal combustion engines. The tester comprises a top cap, a transparent, hollow sightglass attached to the bottom of the cap and a frustro-conical bottom nose-cone attached to the bottom of the sightglass adapted to fit into a radiator inlet. The tester has a longitudinal air-passageway therethrough with a check-ball chamber and check-ball located in the upper portion of the nose-cone. The tester is supplied with water through an upper passageway filled so that approximately one inch of water fills the sightglass. The device is then secured to the radiator filling mouth. If there are pressure leaks from the combustion chamber of the engine into the cooling jacket. When the engine is running, air bubbles can be observed in the sightglass.