The provided "short answer" is incomplete and potentially dangerous if misapplied to brake bleeding procedures. It appears to be referring to a specific component check, not the overall process of bleeding hydraulic brakes. Therefore, this response will focus on the GENERAL process of bleeding hydraulic brakes to remove air, and then address the provided reference.
Bleeding Hydraulic Brakes: The General Process
Bleeding hydraulic brakes removes air bubbles from the brake lines. Air compresses, unlike brake fluid, leading to a spongy brake feel and reduced braking performance. Here's a common method:
1. Gather Your Supplies:
- Brake Fluid: Use the correct type specified in your vehicle's manual. Never mix different types of brake fluid.
- Bleeder Wrench: This specialized wrench fits the bleeder valve on your brake calipers/wheel cylinders.
- Clear Tubing: Fits snugly over the bleeder valve.
- Catch Container: To collect the old brake fluid.
- Assistant (optional, but highly recommended): Makes the process much easier.
- Gloves: To protect your hands from brake fluid.
- Safety Glasses: To protect your eyes.
- Shop Rags: For cleanup.
2. Locate the Bleeder Valves:
Each brake caliper or wheel cylinder has a bleeder valve. These are usually small screws with a nipple extending from them.
3. Prepare the Bleeder Valve:
- Clean the area around the bleeder valve.
- Attach one end of the clear tubing to the bleeder valve.
- Place the other end of the tubing into the catch container, ensuring the end is submerged in a small amount of brake fluid (this prevents air from being sucked back in).
4. The Bleeding Process (Two-Person Method):
- Assistant: Slowly and firmly press the brake pedal down.
- You: Open the bleeder valve (usually about ¼ to ½ turn) while the pedal is depressed. Air and fluid will flow through the tubing.
- Assistant: Hold the brake pedal down until you close the bleeder valve.
- You: Close the bleeder valve.
- Assistant: Slowly release the brake pedal.
- Repeat steps 1-5 until no more air bubbles are visible in the tubing and only clear, bubble-free brake fluid flows out.
- IMPORTANT: Continuously check the brake fluid reservoir in the master cylinder and add fluid as needed to prevent it from running dry. Running the master cylinder dry will introduce more air into the system, requiring you to start the bleeding process over.
5. The Bleeding Process (One-Person Method):
- You can use a one-way bleeder valve or a vacuum bleeder kit. These allow you to open the bleeder valve and pump the brakes yourself without air being sucked back in. Follow the instructions specific to the kit you are using.
6. Repeat for Each Wheel:
Start with the wheel farthest from the master cylinder and work your way closer. The typical order is:
- Right Rear
- Left Rear
- Right Front
- Left Front
However, always consult your vehicle's service manual for the recommended bleeding sequence.
7. Final Checks:
- Ensure all bleeder valves are properly tightened.
- Top off the brake fluid reservoir to the correct level.
- Pump the brake pedal several times to ensure a firm pedal feel.
- Test drive the vehicle carefully in a safe area to ensure the brakes are functioning properly.
Addressing the Reference: "Remove floating piston assembly and blow with mouth into small hole on face of piston. If air Passes, replace with new part."
This refers to a specific diagnostic check for a brake caliper piston seal, not the general brake bleeding process. It describes a way to test the integrity of the seal on the piston itself. If air can pass through the piston when you apply air pressure, it indicates a leak and necessitates replacing the piston or the entire caliper assembly. This is NOT a method for bleeding the brakes.
This procedure should only be performed by a qualified mechanic. Incorrect assembly or diagnosis could lead to brake failure.
