OEM 2004 Cadillac DeVille Brake Master Cylinder

2004 Cadillac DeVille Parts Questions & Experts Answers

• Q: How to service and repair the Brake Master Cylinder on 2004 Cadillac DeVille?

  A: To service and repair the Brake Master Cylinder, first lock the mounting flange in a bench vise, this will help in accessing the rear of the primary Piston. Mex the master cylinder reservoir cap and diaphragm and then fit suitable fittings to the master cylinder ports that can fit the seat size and accommodate hose attachment. Connect transparent hoses to these fittings and direct them back into the master cylinder reservoir. Fill the reservoir to at least the half way mark with delco supreme 11, gm p/n 12377967 (Canadian P/N 992667) or equivalent dot-3 brake fluid from a clean, closed container, making sure the ends of the hoses are totally submerged in the fluid. With a smooth, round-ended tool, depress and release the primary Piston to a depth of approximately 25 mm (1 inch) several times and check for a flow of the fluid from the ports. When air is bled out of the primary and secondary pistons, there will be an associated effort to depress the primary Piston and its travel will be less. Repeat this process until fluid will freely flow without air bubbles coming out from the ports. Next, take off the transparent hoses from the reservoir, then replace the master cylinder reservoir cap and diaphragm, and remove the fittings with the hoses from the ports wrapping the master cylinder with a clean shop cloth to avoid spills. Lastly, loosen the master cylinder from the web of vise.