A handheld vacuum pump is a versatile diagnostic tool. It features a pistol-grip pump handle, a pressure gauge, and various hoses and fittings. By squeezing the handle, you pull vacuum pressure through the hose. Mechanics use it to test vacuum-operated components like turbocharger wastegates, EGR valves, brake boosters, and HVAC blend doors. By applying vacuum directly to the part, you can see if it operates and holds pressure without leaks.
The tool is also commonly used to bleed brakes. By attaching a fluid jar to the line, you connect the hose to a caliper bleeder screw and pump the handle. This pulls brake fluid and trapped air out of the caliper without needing another person to pump the brake pedal. Keep the pump clean of brake fluid, as the fluid will ruin the internal seals of the pump mechanism.