Troubleshooting Bicycle Disk Brakes

Here is a list of common issues that can occur with disc brakes on a bicycle, along with troubleshooting steps and fixes:

1. Squeaking or squealing noise:

   • Symptoms: High-pitched noise when applying the brakes.
   • Troubleshooting:
     • Clean the brake rotor and brake pads to remove any dirt or debris that may be causing the noise.
     • Inspect the brake pads for wear. If they are worn unevenly or have become contaminated, they may need to be replaced.
   • Fix:
     • Clean the brake rotor with isopropyl alcohol or a specialized disc brake cleaner.
     • Remove the brake pads and lightly sand them with fine-grit sandpaper to remove any glazing or contamination.
     • Reinstall the brake pads and ensure they are properly aligned with the rotor.
     • Bed in the brake pads by gradually applying the brakes and progressively increasing the force until the noise diminishes.

2. Brake lever feels spongy:

   • Symptoms: Excessive lever travel, poor braking response, lack of firmness.
   • Troubleshooting:
     • Check for air in the brake system or insufficient brake fluid.
   • Fix:
     • Start by bleeding the brake system to remove any air bubbles and ensure proper fluid circulation.
     • Follow the manufacturer's instructions or seek professional help if you are unfamiliar with the bleeding process.
     • If bleeding doesn't resolve the issue, inspect the brake hoses for leaks or damage. Replace any damaged hoses.
     • Check for proper alignment of the brake caliper and rotor, ensuring there is no interference or rubbing.
     • Adjust the brake lever reach if needed, ensuring a comfortable position for your hand.

3. Brake pads worn out:

   • Symptoms: Reduced braking performance, longer stopping distances, visible wear on the brake pads.
   • Troubleshooting:
     • Inspect the brake pads for wear. If the pad material is worn down to the wear indicators or below, they need to be replaced.
   • Fix:
     • Remove the old brake pads.
     • Install new brake pads that are compatible with your disc brake system.
     • Ensure the brake pads are properly aligned with the rotor.
     • Follow the manufacturer's instructions for proper bedding-in of the new brake pads.
     • Test the braking performance and make further adjustments if necessary.

4. Brake rotor contamination:

   • Symptoms: Poor braking performance, inconsistent braking, vibration or pulsation when applying the brakes.
   • Troubleshooting:
     • Check for oil, grease, or other contaminants on the brake rotor.
   • Fix:
     • Clean the brake rotor thoroughly with isopropyl alcohol or a specialized disc brake cleaner.
     • If the rotor is severely contaminated or damaged, it may need to be replaced.
     • Inspect the brake pads for contamination as well. Clean or replace them as necessary.
     • Check the brake caliper alignment and adjust if needed.
     • Bed in the brake pads to restore optimal braking performance.

5. Sticky or seized brake caliper:

   • Symptoms: Brakes not fully releasing, uneven or inconsistent braking, excessive heat buildup.
   • Troubleshooting:
     • Observe the movement of the brake caliper when applying and releasing the brakes.
   • Fix:
     • Check for any debris, rust, or corrosion on the brake caliper and its moving parts.
     • Clean the caliper thoroughly and lubricate any necessary contact points with an appropriate lubricant.
     • Ensure the brake caliper pistons move freely and retract properly.
     • If the caliper is severely damaged or worn, it may need to be replaced.
     • Verify proper alignment of the caliper with the rotor and adjust if necessary.

If you are unsure about performing any disc brake repairs or adjustments, or if the issue persists after troubleshooting, it is highly recommended to seek assistance from a professional bicycle mechanic to ensure the brakes are properly diagnosed and repaired for safe riding.

Troubleshooting Bicycle Caliper Brakes

Here is a list of common issues that can occur with caliper brakes on a bicycle, along with troubleshooting steps and fixes:

1. Brake pads worn out:

   • Symptoms: Reduced braking performance, screeching or squealing noise, excessive brake lever travel.
   • Troubleshooting:
     • Visually inspect the brake pads for wear. If the pad material is worn down to the wear indicators or below, they need to be replaced.
   • Fix:
     • Remove the old brake pads.
     • Install new brake pads that are compatible with your caliper brakes.
     • Ensure the brake pads are properly aligned with the braking surface.
     • Adjust the position of the brake pads if necessary.
     • Test the braking performance and make further adjustments if needed.

2. Misalignment of brake pads:

   • Symptoms: Uneven braking, scraping noise, reduced braking efficiency.
   • Troubleshooting:
     • Observe the position of the brake pads relative to the rim or braking surface. Look for signs of one pad contacting the rim before the other.
   • Fix:
     • Loosen the brake pad mounting bolt or nut.
     • Align the brake pads symmetrically on either side of the rim, ensuring they make even contact when the brake is applied.
     • Tighten the mounting bolt or nut while holding the brake pads in place.
     • Check for proper alignment and make further adjustments if necessary.
     • Test the braking performance.

3. Brake cable tension issues:

   • Symptoms: Spongy or loose brake lever feel, excessive brake lever travel, inadequate stopping power.
   • Troubleshooting:
     • Squeeze the brake lever and observe the amount of lever travel and the responsiveness of the brake caliper.
   • Fix:
     • Locate the barrel adjuster on the brake caliper or brake lever.
     • Turn the barrel adjuster clockwise to increase cable tension or counterclockwise to decrease tension.
     • Make small adjustments and test the brake lever feel and stopping power after each adjustment.
     • Ensure the brake pads are making even contact with the rim or braking surface.
     • If cable tension adjustments do not improve brake performance, inspect the brake cable for fraying or damage. Replace the cable if necessary.

4. Sticky or dirty brake caliper:

   • Symptoms: Brakes not releasing fully, uneven braking, poor modulation.
   • Troubleshooting:
     • Inspect the brake caliper for dirt, debris, or signs of corrosion.
   • Fix:
     • Clean the brake caliper using a mild solvent or degreaser and a clean cloth.
     • Ensure that all moving parts of the caliper, such as pivots and springs, are clean and lubricated.
     • Check for proper alignment of the caliper arms and brake pads.
     • Test the brake operation, ensuring smooth engagement and disengagement.
     • If cleaning and lubrication do not resolve the issue, consider replacing the caliper if it is severely worn or damaged.

5. Worn or damaged brake cables:

   • Symptoms: Excessive brake lever travel, decreased braking power, fraying or broken cables.
   • Troubleshooting:
     • Inspect the brake cables for signs of fraying, rust, or damage.
   • Fix:
     • If the cables are frayed or damaged, they should be replaced with new ones.
     • Loosen the cable anchor bolt on the brake caliper to release tension.
     • Remove the old cable from the brake lever and caliper.
     • Install the new cable, ensuring proper routing and tension.
     • Secure the cable with the anchor bolt on the caliper.
     • Adjust the cable tension using the barrel adjuster.
     • Test the braking performance and make further adjustments if necessary.

Remember, if you encounter any difficulties or are unsure about performing brake repairs or adjustments, it is recommended to seek assistance from a professional bicycle mechanic for proper diagnosis and repair to ensure your brakes are functioning safely and effectively.

The Rusty Brake Cables Story

Someone (a bike mechanic) emailed me this story:

I was elbow-deep in a tune-up when a disheveled customer walked into the shop, looking like he had seen a ghost. I greeted him and asked how I could help.

He replied, "I had a gnarly accident on my bike yesterday. I was cruising down a steep hill when I went to apply my brakes, but they didn't work. I couldn't stop, and I crashed into a fence."

I couldn't help but raise an eyebrow and ask, "Did you forget to check your brakes?"

The customer looked sheepish and admitted, "I haven't had a tune-up in years. I guess I forgot to check my brake cables for rust."

I couldn't resist the opportunity to tease him and quipped, "Well, now you know what it feels like to be a human cannonball!"

After the initial shock wore off, I got to work inspecting the bike. Sure enough, the brake cables were rusted and needed to be replaced. I also noticed some other areas of the bike that needed attention and recommended a full tune-up.

The customer agreed, and I set to work repairing and tuning the bike. As I worked, I joked with the customer about his daredevil stunt and stressed the importance of regular maintenance and safety checks.

Finally, the bike was ready, and the customer took it for a spin around the shop. He returned with a grin on his face and exclaimed, "It feels like a brand new bike! Thanks for fixing it and for the laughs."

I gave him a wink and replied, "No problem. Just remember, if you're gonna be a human cannonball, you better make sure your brakes are in tip-top shape!"

 

...

So yeah. You can tell this story is completely fabricated. Nobody says "gnarly" any more. I see this anecdotal story as being a bit like a fable that is supposed to teach a lesson, and that is the true lesson of this story.