What you'll need:
* Brake fluid: Use DOT 3 brake fluid (check your owner's manual to be sure). Do not use DOT 5 silicone-based fluid unless specifically called for in your manual, as it's incompatible with most brake systems.
* Bleeding wrench: A wrench that fits your bleeder valves (usually 8mm or 10mm). A bleeder wrench with a hose attachment is highly recommended to make the process cleaner.
* Clear tubing: Long enough to reach a container.
* Container: To catch the old brake fluid.
* Socket wrench: For removing the filler cap of the master cylinder.
* Wrench or pliers: For holding the bleeder valve open
* Helper: To pump the brake pedal.
* Clean rags or paper towels: For spills.
* Gloves: To protect your hands from brake fluid.
* Owner's Manual: Always refer to this for specific instructions and torque specs for your vehicle.
Steps:
1. Prepare the Vehicle: Park the Astro van on a level surface and engage the parking brake firmly.
2. Locate the Bleeder Valves: These are located on each wheel caliper. The Astro van has a rear drum brake system, so they are located at the back of the rear wheel cylinders. There are typically two bleeder valves per rear wheel. The front brakes are disc brakes with a single bleeder valve per caliper. Locate the bleeder valves on all four corners.
3. Fill the Master Cylinder: Open the master cylinder's reservoir cap and check the fluid level. Top it off with fresh DOT 3 brake fluid. Keep an eye on the level throughout the bleeding process; it will decrease as you bleed the brakes.
4. Attach the Tubing: Attach one end of the clear tubing to the bleeder valve and the other end to your container. Make sure the tubing is secure and won't come off during the process.
5. Bleeding Sequence: The standard bleeding sequence is Rear Passenger, Rear Driver, Front Passenger, Front Driver. This is important to ensure even bleeding and avoid air pockets. *Some mechanics prefer to start at the furthest point from the master cylinder (Rear Passenger).*
6. Bleeding Process (Per Wheel):
* Have your helper slowly and firmly pump the brake pedal several times.
* *Hold* the bleeder valve open just slightly with your wrench. Your helper should feel the pedal go to the floor and then come up.
* Close the bleeder valve. This is crucial - *do not hold it open for long or you will introduce air into the system.* Your helper should repeat the pumping action until the fluid runs clear and free from air bubbles.
* Repeat this process until no more bubbles are seen in the tubing. Check the fluid level in the master cylinder frequently and refill as needed.
* Once done, tighten the bleeder valve securely.
7. Repeat for Each Wheel: Follow the sequence and repeat steps 6 for each wheel, in the specified order.
8. Check Brake Pedal: Once all four wheels are bled, have your helper pump the brake pedal several times. It should feel firm and responsive. If not, repeat the bleeding process, paying close attention to any wheel that may still have air in the system.
9. Check Fluid Level: After bleeding, top off the master cylinder reservoir with fresh DOT 3 brake fluid. Wipe up any spilled brake fluid.
Important Considerations:
* Air in the System: If you struggle to get a firm pedal after bleeding, there may be a more serious problem (like a leak or a faulty master cylinder) that requires professional attention.
* Brake Fluid is Corrosive: Brake fluid is corrosive and can damage paint. Clean up any spills immediately.
* Power Bleeding: A power bleeder can make the process easier and more efficient, but it is not essential for this task.
* Professional Assistance: If you are uncomfortable performing this task yourself, it is always best to take your Astro van to a qualified mechanic. Bleeding brakes improperly can lead to brake failure, which is extremely dangerous.
This guide provides a general overview. Always refer to your vehicle's owner's manual for specific instructions and recommendations. Safety first!
