However, if you're determined to bench bleed the master cylinder, here's how, bearing in mind the limitations:
Tools Required:
* New master cylinder: Unless you've already rebuilt the existing one. It's easier and safer to start with a known-good component.
* Brake fluid: Use the correct type specified for your Grand Prix (check your owner's manual). DOT 3 or DOT 4 are common. Never mix different types of brake fluid.
* Clear tubing: Long enough to reach a container.
* Funnel: To pour brake fluid into the master cylinder reservoir.
* Two helpers: Bench bleeding is more manageable with two helpers.
* Sockets and wrenches: To remove and reinstall the master cylinder (if necessary).
* Clean rags or paper towels: For spills.
* Gloves: To protect your hands.
Procedure:
1. Prepare the master cylinder: Install the master cylinder cap. If your master cylinder has two ports, you'll need a fitting for one port to feed into the tubing and also a helper for the other. If it has one port, only one helper is needed. The ports usually have a different size fitting for each, so you may need additional adaptors.
2. Connect the tubing: Attach one end of the clear tubing securely to the outlet port(s) of the master cylinder, making sure there are no leaks. The other end should go into a container filled with brake fluid. The container helps to prevent air from being sucked back in. Make sure the container is below the master cylinder.
3. Fill the reservoir: Fill the master cylinder reservoir with fresh brake fluid, keeping an eye on the level as you work.
4. Pump the plunger(s): Two helpers are better. One helper pushes the plunger(s) in and out, slowly and smoothly. The other helper continuously tops off the reservoir with fresh brake fluid. The goal is to completely purge all of the air through the tubing. This should result in a continuous flow of brake fluid and minimal bubbles emerging from the tubing. If the fluid looks bubbly, you may need to continue pumping.
5. Check for bubbles: Carefully observe the tubing for any bubbles. Continue pumping until the fluid flows clear and free of bubbles.
6. Reinstall the master cylinder: Once you've eliminated all air, carefully install the master cylinder in the vehicle.
Important Considerations:
* Air in the lines: Even after bench bleeding, there might still be air trapped in the brake lines. You'll still need to bleed the brakes at each wheel individually.
* ABS: If your Grand Prix has ABS, bench bleeding is even less effective and you'll almost certainly need professional-grade bleeding equipment to bleed the system correctly.
* Fluid type: Use only the recommended brake fluid for your car. Using the wrong fluid can damage the system.
* Safety: Brake fluid is corrosive. Avoid contact with skin and eyes. Work in a well-ventilated area.
Recommendation: Save yourself the time, potential frustration, and risk of incomplete bleeding. Take your vehicle to a qualified mechanic to properly bleed the brakes. This is especially important if you have ABS. Improperly bled brakes are dangerous.
