Disconnect the negative cable at the battery and place it out of the way to prevent accidental contact with the negative terminal. Place newspapers or rags under the Brake Master Cylinder to catch any leaking brake fluid, then disconnect the low fluid level sensor electrical connector. Use a flare nut wrench to loosen the nuts securing the
Brake Lines to the Brake Master Cylinder and remove the two nuts securing the Brake Master Cylinder to the vacuum servo unit. Carefully lift the cylinder off the mounting studs, remove the brake lines, and immediately cover the holes to prevent fluid leakage before lifting the cylinder out of the engine compartment. Plug the fluid lines to prevent further leakage. Before installing the new Brake Master Cylinder, bench bleed it by mounting it in a vice, ensuring not to clamp too tightly. Insert threaded plugs into the brake line outlet holes and snug them down to prevent air leakage. Fill the reservoir with the recommended brake fluid, then remove one plug and push the piston assembly into the Brake Master Cylinder bore to expel air, using a large Phillips screwdriver if necessary. Replace the plug before releasing pressure on the piston assembly and repeat until only brake fluid is expelled. An alternative method involves covering the hole with a finger instead of replacing the plug, allowing brake fluid to be drawn in before depressing the piston again. After completing the bleeding for one outlet, replace the plug and snug it before moving to the other port. Install the Brake Master Cylinder onto the vacuum servo retaining studs and fasten it, then attach the fluid lines using a flare nut wrench and reconnect the low fluid level sensor electrical connector. Top up the fluid level in the Brake Master Cylinder reservoir between the Max and Min marks, bleed the entire brake system, and remove the newspapers from underneath the Brake Master Cylinder, taking care not to drip fluid on painted surfaces. Finally, reconnect the negative ground cable at the battery.