However, a *completely* empty master cylinder *could* need attention. This is rare unless there's been a major leak or repair. If you suspect this, you'll need to:
1. Safety First: Engage the parking brake firmly. Have a helper. Wear safety glasses.
2. Locate the Master Cylinder: It's typically under the hood, near the firewall. Consult your repair manual for the exact location.
3. Check the Fluid Level: Open the master cylinder reservoir and check the fluid level. If it's empty, carefully add the correct brake fluid (consult your owner's manual for the correct type – DOT 3 or DOT 4 are common). Never let the reservoir run completely dry. Air entering the master cylinder is much harder to deal with.
4. Bleeding the Brake Lines: This is where the actual bleeding takes place. You'll need to bleed the brakes at each wheel, starting with the furthest wheel from the master cylinder (typically a rear wheel, then the other rear, then front passenger, then front driver). This process usually involves:
* Opening a bleeder valve: Located on each caliper (disc brakes) or wheel cylinder (drum brakes).
* Pumping the brake pedal: Your helper slowly and steadily pumps the brake pedal.
* Closing the bleeder valve: After the pedal firms up.
* Repeating the process: Until no more air bubbles are visible in the fluid.
* Maintaining Fluid Level: Your helper needs to monitor and add fluid to the master cylinder reservoir to avoid it running low.
5. Professional Help: If you're not comfortable bleeding your brakes, it's best to take your car to a qualified mechanic. Improper bleeding can lead to brake failure, which is extremely dangerous.
In summary: You don't bleed the master cylinder directly. A soft brake pedal almost always points to air in the brake lines. If the master cylinder reservoir is empty, refill it *carefully*, then bleed the brakes properly. If you're unsure about any step, consult a repair manual for your specific 1994 Pontiac Sunbird or seek professional help.
