What you'll need:
* Brake fluid: Use DOT 3 brake fluid (check your owner's manual to be sure). Important: Never use anything other than the specified type. Brake fluid is hygroscopic (absorbs moisture), so using old or contaminated fluid can cause brake failure.
* Bleeding wrench: A wrench that fits the bleeder valve on your calipers and wheel cylinders. This is usually a 8mm or 10mm, but double-check yours.
* Clear tubing: A length of clear plastic tubing (about 2 feet) to fit over the bleeder valve.
* Container: A jar or bottle to catch the old brake fluid.
* Assistant: Having someone pump the brake pedal is essential.
* Gloves: Brake fluid is corrosive, so protect your skin.
* Shop rags or paper towels: For cleanup.
* Owner's Manual: (Highly Recommended) Consult it for specific details about your Sonoma's brake system.
Procedure:
1. Prep: Park your Sonoma on a level surface, engage the parking brake firmly, and ensure the engine is off. Locate the bleeder valves on each caliper (usually located on the top or side of the caliper) and wheel cylinder (if you have rear drum brakes). You'll need to remove the wheels to access the rear wheel cylinders.
2. Find the correct bleeding order: The correct order is crucial. The furthest point from the master cylinder should be bled first. Generally, this is:
* Rear passenger side (Right Rear): This is usually the furthest point.
* Rear driver side (Left Rear):
* Front passenger side (Right Front):
* Front driver side (Left Front):
Important Note: While this is the typical order, double check your owner's manual as some models may vary slightly.
3. Open the bleeder valve slightly: Attach the clear tubing to the bleeder valve and direct the other end into the container. Use the wrench to slightly crack open the bleeder valve. Be careful not to open it too far initially.
4. Have your assistant pump the brake pedal: Have your assistant slowly and firmly pump the brake pedal several times. They should hold the pedal down on the last pump.
5. Open and close the bleeder valve: While your assistant holds the pedal down, completely open the bleeder valve to allow air and old fluid to escape. You should see a steady stream of brake fluid with bubbles initially and then the bubbles will subside. Close the bleeder valve once the flow of fluid is steady and no longer has bubbles.
6. Repeat: Have your assistant release the brake pedal and repeat steps 4 and 5 several times until no more air bubbles are visible in the fluid. If there is a noticeable pause in the flow of brake fluid before the next pump, tighten up the bleeder screw slightly and then open it again.
7. Bleed the other calipers/wheel cylinders: Repeat steps 3-6 for each wheel, following the correct bleeding order mentioned above. Make sure to keep the brake fluid reservoir topped off to prevent air from entering the system. Check the level frequently!
8. Check the brake pedal: Once all the wheels are bled, have your assistant pump the brake pedal several times again. The pedal should feel firm and responsive. If not, there's likely still air in the system, and you may need to repeat the bleeding process.
9. Clean up: Clean up any spilled brake fluid and replace the wheel(s).
10. Test drive: After bleeding the brakes, test drive your Sonoma in a safe, controlled environment, like an empty parking lot, to ensure the brakes are working correctly.
Important Considerations:
* Low Fluid Level: If the brake fluid reservoir runs low, you risk introducing air into the system. Always keep an eye on the level and refill as needed.
* Brake System Issues: If you're having trouble bleeding the brakes, or if the brakes feel spongy or weak after bleeding, there could be a more serious issue with the brake system. It's best to have a mechanic inspect the system.
* Safety First: Brake fluid is corrosive. Wear protective gloves and eye protection. Be extremely careful not to get brake fluid on your painted surfaces.
If you're not comfortable performing this task yourself, it's always best to take your Sonoma to a qualified mechanic. Improperly bled brakes can be extremely dangerous.
