Master Cylinder Trouble Shooting

If your Corvette's master cylinder has an external leak,it's obvious it's time to either rebuild or replace it but if brake fluid bypasses an internal pressure seal of the master cylinder you will get a pedal that fades without fluid loss. The following test will identify if a cylinder is bad and if not, will help pinpoint whether there's a problem with the front or back half of your brake system

1. Disconnect the brake lines from the master cylinder but leave the cylinder bolted in place.

2. Plug both master cylinder outlets using solid inverted flare plugs with the correct threads. You can find these at auto parts stores.

3. With both master cylinder outlets plugged, depress the pedal. If the pedal is very spongy or goes to the floor, the master cylinder is bad. If you have a good firm pedal then the master cylinder is fine.

4. If you have a firm pedal, connect the line to the front portion of the brake system and try the pedal again. If the pedal remains firm then the front part of the system is fine. If the pedal goes to the floor, the problem is with the front half of the system.

5. If the pedal is fine with the front part of the system connected then connect the rear portion . If the pedal goes to the floor then the problem is in the rear.

6. Once you know which portion of the system has the problem then it will be easier to track down exactly what part is causing the problem.