how to bleed rear brakes on motorcycle

3 min read 17-01-2025

Meta Description: Learn how to bleed your motorcycle's rear brakes effectively with our comprehensive guide. We cover tools, techniques, and troubleshooting, ensuring safe and efficient brake bleeding for optimal performance. Avoid costly mechanic visits with our step-by-step instructions and helpful tips for a successful DIY brake bleed.

Why Bleed Your Rear Motorcycle Brakes?

Air in your motorcycle's rear brake lines is a serious issue. It significantly reduces braking power, making your rides unsafe. This can happen due to various reasons, including:

Brake fluid leaks: A small leak can introduce air into the system.
Old brake fluid: Degraded fluid can absorb moisture, leading to air pockets.
Brake system repair: Work on the calipers or master cylinder can introduce air.

Bleeding your brakes is essential to remove this air, restoring full braking performance and ensuring your safety. Regular bleeding as part of your motorcycle maintenance is highly recommended.

Tools You'll Need

Before you begin, gather these essential tools:

New brake fluid: Use DOT 4 or DOT 5.1 fluid, depending on your motorcycle's specifications. Never mix different types.
Clear tubing: This allows you to see the fluid and air bubbles.
Bleeding wrench: This is specifically designed for brake bleed nipples; a standard wrench may damage the nipple.
Container: To catch the old brake fluid.
Gloves: Protect your hands from brake fluid, which can irritate skin.
Clean rags: For cleaning spills and keeping the area tidy.
Shop towels: A helpful addition for keeping your hands and the bike clean.
Owner's manual: Consult your bike's manual for specific instructions and torque specifications.

Step-by-Step Guide to Bleeding Rear Motorcycle Brakes

Note: Always consult your motorcycle's service manual for specific instructions and torque specifications. These steps provide a general guideline.

1. Preparation:

Park your motorcycle on a level surface and engage the kickstand. Ensure the bike is stable.
Locate the rear brake caliper and master cylinder. Your owner's manual will show the exact locations.
Protect the surrounding areas with clean rags or shop towels to prevent fluid spills.

2. Open the Bleeder Valve:

Use your bleeding wrench to slightly loosen the bleeder valve on the rear brake caliper. Don’t remove it completely.

3. Attach the Tubing:

Attach one end of the clear tubing to the bleeder valve. Submerge the other end in your container filled with brake fluid. This prevents air from re-entering the system.

4. Pump the Brake Lever:

Have a helper pump the rear brake lever firmly and repeatedly. This pushes the fluid and air through the system.

5. Open and Close the Bleeder Valve:

While your helper pumps the brake lever, slightly open the bleeder valve to release the fluid and air bubbles. You should see bubbles coming through the tubing. Close the valve immediately after each pump.

6. Repeat the Process:

Repeat steps 4 and 5 until only clear brake fluid, free of air bubbles, flows consistently through the tube.

7. Close the Bleeder Valve:

Once all air bubbles are removed, tighten the bleeder valve securely with your bleeding wrench.

8. Check Fluid Level:

Ensure your master cylinder reservoir is topped off with fresh brake fluid.

9. Test the Brakes:

Gently squeeze the rear brake lever. It should feel firm and responsive. Test your brakes carefully and thoroughly before riding.

Troubleshooting

No Fluid Flow: Check if the bleeder valve is open, and ensure your helper is pumping the brake lever correctly. If the problem persists, there may be a more serious issue in the brake system.
Bubbles Still Appear: Try bleeding the system multiple times. A persistent bubble could indicate a leak.
Brake Lever Feels Spongy: After bleeding, it may feel soft, even if there's no more air. This might indicate worn brake pads, or a leak.

Maintaining Your Motorcycle Brakes

Regular maintenance is key to preventing brake problems. This includes checking your brake fluid level, inspecting your brake pads for wear, and bleeding your brakes every six months or as needed.

Conclusion

Bleeding your motorcycle's rear brakes is an essential maintenance task that ensures optimal braking performance and rider safety. By following these steps and troubleshooting tips, you can effectively bleed your brakes and enjoy safer, more confident rides. Remember, always consult your motorcycle's service manual for specific instructions. If you're uncomfortable performing this task yourself, consult a professional mechanic.