Here's how to do it, emphasizing safety and caution:
WARNING: Brake system adjustments are critical for safe operation. If you're not comfortable working on your brakes, take your car to a qualified mechanic. Improper adjustment can lead to brake failure.
Tools You'll Need:
* Socket wrench and sockets: The size will depend on your specific model, likely 7/16" or 9/16" for the pushrod nut.
* Open-end wrench: Possibly needed for a locking nut or retainer clip.
* Safety glasses: Protect your eyes from flying debris.
* Gloves: Keep your hands clean.
* Jack and jack stands: To safely lift the car.
* Wheel chocks: To secure the car.
Procedure:
1. Safety First: Park the car on a level surface, engage the parking brake, and chock the wheels. Lift the car securely using a jack and support it on jack stands.
2. Locate the Pushrod: The pushrod connects the brake pedal to the master cylinder. It's usually accessible under the dash, near the firewall. You'll likely need to remove some trim panels to access it.
3. Adjust the Pushrod: The pushrod will have an adjustment mechanism, usually a nut that allows you to lengthen or shorten the rod. This is where the careful adjustment comes in.
4. Initial Adjustment (Approximation): If there's excessive pedal travel, you'll need to shorten the pushrod. Start by making a small adjustment (1/8 to 1/4 turn at most). If the pedal feels too firm or there's insufficient travel, lengthen the pushrod by the same small increment.
5. Testing: After each adjustment, carefully lower the car *slowly* (check the stability of your jack stands frequently). Pump the brake pedal several times to bleed out any air that might have been introduced. Then, test the brakes thoroughly and carefully in a safe, empty area at low speed. *Never* test brakes on a public road until they feel completely safe and responsive.
6. Iterative Adjustment: Repeat steps 4 and 5, making small adjustments until you achieve the correct pedal feel and stopping power. The goal is a firm pedal with minimal travel before the brakes engage. Avoid making large adjustments at once.
7. Proper Pedal Feel: A properly adjusted brake pedal should have a firm, positive feel, without excessive spongy action. It should require only a moderate amount of pressure to stop the vehicle effectively.
8. Bleeding the Brakes (Potentially Necessary): After making adjustments, you might need to bleed the brakes to remove any air introduced during the process. This is a separate procedure and requires two people, one to pump the brakes and one to open the bleeder valves. Consult your car's repair manual for the proper bleeding sequence.
9. Reassembly: Once you've achieved proper brake pedal feel and stopping power, carefully reassemble any trim panels or access covers you removed.
Important Notes:
* Consult a repair manual: A factory service manual for your 1969 Pontiac Firebird will provide specific diagrams and instructions for your model. This is highly recommended.
* Brake fluid: Always check the brake fluid level in the master cylinder reservoir. Add fluid if necessary; you will likely need to top it up after the adjustment.
* Master Cylinder Condition: If your master cylinder is worn or leaking, adjusting the pushrod won't solve the underlying problem, and new components will likely be needed.
Remember, brake safety is paramount. If you are uncomfortable performing this task, consult a professional mechanic. Improper brake adjustments can be dangerous.
