Introduction

• Changing the brake master cylinder on a Ford Mustang only requires a few tools: a Phillips screwdriver, set of sockets, ratchet, a 6-inch extension and a set of line wrenches. It would be a good idea to have a couple rags handy to keep brake fluid from getting all over as the lines are taken off and, of course, a bottle of brake fluid.
  
  

Removing the Old Master

• Break the two brake lines loose at the master cylinder with the line wrenches, but do not take them off yet. Just get them loose enough to get off easily. Remove the electrical connector from the master. Remove the two nuts holding the master cylinder to the power brake booster with the sockets and extension. Remove the brake lines and pull them out of their cavities just enough to pull the master cylinder off. Remove the master cylinder then remove the cap and drain the fluid.
  
  

Bleeding the New Master

• Take the new master cylinder out of the box along with the two bleeder hoses and plastic caps that should have come with the master cylinder. Lay the master cylinder on a bench and install the plastic caps into the openings for the brake lines. Attach the hoses supplied with the master and hold the other end into the top of the master cylinder. Fill the master cylinder with brake fluid and keep the hoses submerged in the fluid during this bleeding process. Now the master must be bled of air and all chambers filled with fluid. To do this, the master cylinder plunger all the way in slowly with the Phillips screwdriver. Let the plunger out. Each time this is done, notice the air bubbles in the brake fluid in the master cylinder reservoir. Keep doing this until all the air is gone.
  
  

Installing the New Master

• Keep the hoses in the fluid and install the master back onto the studs on the brake booster. A small amount of fluid will be lost when the hoses come off but this is nothing to worry about because this is normal. The master cylinder plunger will still retain all the fluid, however it is still desirable to install the lines a fast as possible to lessen the fluid loss. This way the brakes won't have to be bled further. Take one line off at a time and install the brake line finger tight and go to the next one. Once they are on give them at small snug with the line wrench. Install the nuts on the studs of the brake booster holding the master on and tighten. Tighten the brake lines on the master cylinder. Fill the reservoir to just below the cap and install the cap and the electrical pressure connector. Clean the area off with the rags.