After buying a new set of tires, a mechanic noted that he saw brake fluid dripping from one of the brake calipers, near where the hose connecting it to the rest of the car met the caliper. (The caliper is the hydraulic clamp that actually grabs the brake pads / rotor to stop the car.) I do all of the work on my car myself, so I bought a replacement hose and caliper. My car is pretty ancient (1986), so at the first sign of trouble I like to replace anything that could be a problem with new parts.
Unfortunately, the threaded pipe fitting where the hose connects to the metal pipe that goes to the rest of the car was rusted quite solidly. I tried to use a rust penetrating oil (parts blaster) and let it soak for a few days, but to no effect.
One trick that is used by mechanics to loosen rusty objects is to use thermal expansion to fracture the rust layer between them. The thermal expansion of the outer object (such as a nut) creates enough stress to break the rust, and the rust acts... keep reading on reddit ➡