Bleeding the brake system on a C3 Corvette is actually not that complicated when compared to other models. Once you understand the physics of it all, it’s fairly easy to do yourself.
To get started bleeding your brakes remember these 2 steps:
1. Master Cylinder
2. Caliper – inner half first
First, you need to remove all the air from the Master Cylinder. To bleed the Master Cylinder, you need fittings & tubes to route the fluid from the exit ports back into the reservoir on top. These were previously included with a new Master Cylinder, but you can make your own by buying short pieces of brake line and bending it.
Install the tubes & press the Master Cylinder pedal until you get a solid, bubble-free flow all around. The master cylinder is mounted at an angle in the car so air bubbles can get trapped in the highest point of the bore… so try to level it to prevent this.
To test the master cylinder, remove the tubes and replace them with inverted flare plugs, being careful not to allow more than a few drops of fluid to run out of the ports when you switch over to plugs from tubes. Now press on the master cylinder pedal again – it should barely budge.
Once the master cylinder is finished its time to bleed the lines and calipers. Because C3 Corvettes have a brake switch or proportion valve, bleeding the lines and calipers can be tricky. This valve is designed to maintain appropriate hydraulic pressure to the brakes to prevent malfunction – in other words, it will cut off the supply of fluid to one brake line if pressure drops too low – rendering it impossible to bleed. To get around this, you can bleed one front caliper and one rear caliper simultaneously after re-centering the valve.
Now for the actual bleeding of the brakes. There are tons of different ways to do this and everyone has their own method they like to use. Here, we will discuss one such method that works.
Start by opening all of the caliper bleeder screws. You can gravity bleed all or one at a time… place a hose on the bleeder and set it up so that the hose is in the bottom of a Gatorade bottle or container of your choice so no air can travel up the hose backward once there is some fluid in the bottom of the cup. Open bleeders, let the fluid drain, close the bleeders.
If fluid does not start to flow right away, give the master cylinder a few pumps and you should be off an running.
When all of the bleeders are closed, top off the master cylinder. Re-connect the power brake booster hose and your system is bled. You should see fluid start to run out in about 10-15 minutes.
Congratulations, your brake system is bled.
If you need some extra guidance, here is a general tutorial for bleeding your brakes by yourself. Keep in mind the slight variations mentioned above specific to the C3 Corvette.