Brakes are one of the most important safety features on an e-bike. When they feel weak or “spongy,” it can make every ride risky and uncomfortable. Many riders experience this issue after some time, but the good news is that weak brakes can often be fixed with a few simple adjustments and regular maintenance. In this guide, we’ll explain the common causes of weak e-bike brakes and show you how to adjust and maintain them for safe, responsive stopping power.
Common Causes of Soft Brakes
Before fixing the issue, it helps to understand why your brakes might feel soft. Below are the most common reasons.
1. Worn Brake Pads
If the brake pads are too thin, it can increase the braking distance, reduce braking power, and even damage the brake rotor. Regularly check the thickness of your brake pads. Replace them immediately if they are less than 1 mm thick.
2. Low Brake Fluid or Air in the Line
Insufficient brake fluid or air trapped in the brake line can cause the brake lever to feel soft or spongy. If you notice that your brake fluid is low, you can top it up yourself using bike-specific mineral oil.
3. Contaminated Brake Rotor or Rim
If the brake rotor (disc) or rim has oil, water, or cleaning residue on the surface, friction will be greatly reduced, causing the brakes to slip. Use a dedicated brake cleaner to wipe the surface.
4. Misaligned Brake Caliper
A caliper that is not properly aligned with the rotor may result in uneven braking force and can even cause rubbing or squeaking noises.
5. Leaking Brake Hose
A damaged or poorly sealed brake hose, connector, or caliper can cause fluid leakage. This not only reduces braking power but can lead to complete brake failure. Check the ground under the e-bike and the outside of the brake hose for any signs of fluid leakage.
Solutions for Soft Brakes
After understanding the common causes of soft brakes, the next step is to take effective measures to restore proper braking performance. This section will cover practical solutions, including brake bleeding and caliper adjustment.
1. How to Fix Air in Hydraulic Brakes
When air enters the hydraulic brake system, the brake lever may feel soft or spongy, and braking efficiency will be significantly reduced. To fix this, the brakes need to be bled to remove trapped air and restore proper hydraulic pressure. You can follow the video tutorial below for step-by-step guidance.
2. How to Adjust Brake Calipers
A misaligned brake caliper can cause uneven braking, rubbing, or noise. Adjusting the caliper ensures that the brake pads align correctly with the rotor, restoring proper braking performance.
Adjustment Steps:
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Loosen the Caliper Mounting Bolts
Allow the caliper to move slightly over the rotor.
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Squeeze the Brake Lever
This centers the caliper automatically over the rotor.
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Tighten the Caliper Bolts
While keeping the brake lever squeezed, tighten the mounting bolts to fix the caliper in place.
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Check for Rubbing or Noise
Release the lever and spin the wheel. If there is still rubbing or noise, repeat minor adjustments until the brake spins freely and quietly.
3. Brake Noise Adjustment Video Guide
If your e-bike produces rubbing, squeaking, or other unusual noises when braking, this is usually caused by misaligned brake pads, slightly warped rotors, or incorrect installation gaps. To help you identify the issue more intuitively, we have prepared the following brake noise troubleshooting video.
4. Handling Leaking Brakes
A leak in the brake hose, fittings, or caliper seal can cause brake fluid loss. Once this occurs, braking power decreases and, in severe cases, can lead to complete brake failure.
Steps to Handle Brake Leaks:
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Inspect the Leak Location
- Carefully check the brake hoses, fittings, and calipers to identify the source of the leak.
- Inspect the ground or around the brakes for fluid traces.
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Replace Leaking Components
- If any brake hoses or fittings are damaged, replace them promptly.
- If your e-bike is still under warranty, contact the Aniioki after-sales team. Please provide:
- A video or photo showing the brake leak
- Your order number
Conclusion
A strong and reliable braking system is essential for safe e-bike riding. By checking your brake pads, adjusting cables or calipers, and keeping your brake discs clean, you can often restore braking performance on your own. Regular maintenance not only improves safety but also ensures a smoother, more enjoyable riding experience.
If you need replacement parts or further assistance, feel free to contact our technical support team.
