Noisy or squealing disc brakes can be a frustrating issue for cyclists, especially when the performance of your Shimano BR-R8070 [paid link] hydraulic disc brakes is compromised by unwanted sounds. Fortunately, understanding the root causes of these noises and knowing how to fix them will ensure a quiet, efficient braking experience. This guide will cover common reasons for squealing and provide you with the steps needed to diagnose and resolve these issues effectively.

Understanding the Causes of Noisy or Squealing Brakes

Before diving into solutions, it’s important to understand why your Shimano BR-R8070 [paid link] disc brakes might produce noise. The causes can vary, but here are the most common ones:

1. Contaminated Brake Pads or Rotors: One of the most frequent causes of noise in hydraulic disc brakes is contamination from oil, dirt, or grime. If your brake pads or rotors are exposed to any contaminants, the friction needed for smooth braking is reduced, leading to squealing sounds.
2. Incorrect Pad Alignment: If the brake pads are not aligned correctly with the rotor, uneven contact is made when the brakes are applied. This misalignment can lead to squealing as the pads scrape against the rotor in an inconsistent manner.
3. Worn Brake Pads: Over time, brake pads naturally wear down. When the pad material becomes too thin, the brake system might not perform as expected, which can lead to noise and reduced braking efficiency.
4. Rotor Warping: A warped rotor can cause uneven braking surface contact, leading to pulsating or squealing sounds when the brakes are engaged.
5. Environmental Factors: Weather conditions, such as rain or wet roads, can temporarily cause squealing in your brakes. However, this should resolve after a few braking cycles once the pads dry.

Step-by-Step Guide to Diagnose and Fix Noisy Shimano BR-R8070 Disc Brakes

1. Inspect the Brake Pads for Contamination

The first thing to check when dealing with noisy brakes is the condition of the brake pads. Contaminants such as oil, grease, or dirt can create a barrier between the pad and the rotor, leading to squealing.

How to Check and Clean:

• Remove the brake pads from the caliper.
• Inspect the pads for any visible contamination or excessive wear.
• If the pads are contaminated, clean them with isopropyl alcohol and a clean cloth. Avoid using any harsh chemicals, as they can damage the pads.
• For severe contamination, you may need to replace the pads.

2. Clean the Brake Rotors

Just like the brake pads, the rotors can also accumulate dirt and grime, leading to poor braking performance and noise.

Cleaning Process:

• Clean the rotors with isopropyl alcohol using a clean rag.
• Avoid touching the rotor surface with your fingers, as oils from your skin can contaminate it.
• If the rotors have persistent contamination, you can use a dedicated disc rotor cleaner.

3. Check Brake Pad Alignment

If your Shimano BR-R8070 [paid link] pads are not properly aligned, they will not make even contact with the rotor, which can cause squealing.

How to Check and Adjust:

• Loosen the caliper mounting bolts and ensure that the caliper is centered over the rotor.
• Squeeze the brake lever while adjusting the caliper, ensuring the pads are parallel to the rotor. Once properly aligned, tighten the bolts securely.
• Ensure the brake pads are positioned evenly on both sides of the rotor.

4. Inspect for Rotor Warping

Warped rotors can be a significant contributor to noise. A warped rotor leads to inconsistent contact between the pads and rotor, which can cause squealing.

How to Check for Warping:

• Spin the wheel and visually inspect the rotor. Look for any noticeable wobbling or side-to-side movement.
• If you detect warping, you can use a rotor truing tool to gently straighten the rotor. Be careful not to overcorrect, as this can lead to additional damage.
• If the rotor is significantly bent, replacing it is the best option.

5. Check the Brake Pads for Wear

Over time, the friction material on the brake pads wears down. When the pads become too thin, they can cause noise and reduce braking power.

How to Check for Wear:

• Remove the brake pads and check the thickness of the friction material. Shimano BR-R8070 pads should have a minimum thickness of around 1.5mm to 2mm.
• If the pads are worn beyond this limit, replace them with new ones.

6. Bed in New Pads

If you’ve recently replaced your brake pads, it’s crucial to bed them in properly. Improperly bedded pads can create squealing due to poor contact with the rotor.

How to Bed in New Pads:

• Perform several braking cycles from moderate to hard braking. Each cycle should involve braking from a higher speed to a complete stop.
• This process helps to transfer an even layer of brake pad material onto the rotor, improving performance and reducing noise.

7. Consider Brake Pad Type and Material

Different brake pads are made of various materials, such as organic, sintered, or semi-metallic compounds. Some materials may be more prone to noise, especially under certain conditions like wet or cold weather.

Solution:

• If noise persists despite the steps above, consider switching to a different type of brake pad. For example, sintered pads tend to perform better in wet conditions and may reduce squealing compared to organic pads.

Conclusion

By following these steps, you should be able to effectively diagnose and fix noisy or squealing Shimano BR-R8070 disc brakes. Regular maintenance and inspection of the brake pads, rotors, and alignment will ensure that your brakes perform at their best, keeping noise to a minimum and your rides smooth and safe. If the noise persists despite these efforts, consulting a professional bike mechanic might be necessary for further diagnosis.