What you'll need:
* Brake fluid: Use DOT 3 brake fluid (check your owner's manual to be sure). Never use anything else.
* Brake bleeder wrench: This is usually a 8mm or 10mm (check your vehicle) open-end wrench or a special brake bleeder wrench that fits snugly over the bleeder valve.
* Clear tubing: Long enough to reach a container.
* Container: To catch the old brake fluid.
* Wrench: To hold the caliper bracket (optional but recommended).
* Shop rags or paper towels: To clean up spills.
* A helper: Crucial for this job.
Procedure:
1. Safety First: Wear safety glasses to protect your eyes from splashing brake fluid. Brake fluid can damage paint, so be careful not to spill it. Work in a well-ventilated area.
2. Locate Bleeder Valves: The bleeder valves are located on top of each brake caliper (front and rear). They are typically small, usually hexagonal (6-sided) fittings.
3. Prepare the System: Have your helper sit in the driver's seat with their foot off the brake pedal. Make sure the brake fluid reservoir is topped off with fresh DOT 3 fluid. Do not let the reservoir run dry.
4. Bleeding Order: The standard bleeding order is usually Rear Passenger, Rear Driver, Front Passenger, Front Driver. However, some mechanics prefer to start at the furthest point from the master cylinder (typically the rear passenger side). Always consult your owner's manual for the specific recommended bleeding order for your 1990 Chevy Suburban. This ensures proper air removal.
5. Bleed Each Wheel:
* Attach the clear tubing to the bleeder valve on one wheel and submerge the other end in the container.
* Have your helper slowly and steadily pump the brake pedal several times, then hold it down.
* Open the bleeder valve with your wrench *slowly*. You should see brake fluid flowing through the tube. If there's air present, you may see bubbles.
* Keep an eye on the fluid reservoir level. If needed, refill it between wheels to prevent air from being sucked in.
* Once the flow becomes a steady stream of fluid with no bubbles, close the bleeder valve firmly.
* Repeat steps 5.1-5.7 for each wheel, following the correct bleeding order.
6. Check for Firm Pedal: Have your helper pump the brake pedal a few times. The pedal should feel firm and responsive. If it's spongy, there may still be air in the lines, and you may need to repeat the bleeding process.
7. Check Fluid Level: After bleeding, check and top off the brake fluid reservoir as needed.
8. Test Drive: Take the Suburban for a short test drive and check for proper braking performance. If the brakes feel spongy or unusual after the test drive, you may have a more serious issue, like a leaking line or damaged master cylinder. Consult a mechanic.
Important Notes:
* ABS Systems: If your 1990 Suburban has Anti-lock Braking System (ABS), bleeding the brakes correctly can be more complex and might require specialized tools or a professional mechanic. The ABS module needs to be bled separately and often requires a scan tool.
* Power Brakes: Make sure your engine is running during the bleeding process to provide power assist to the brakes.
* Master Cylinder: A low brake fluid reservoir indicates a leak somewhere in your brake system, which is serious and requires professional attention.
If you are uncomfortable performing this procedure yourself, it's always best to have a qualified mechanic bleed your brakes. Incorrect bleeding can lead to brake failure, which is incredibly dangerous.
