How to Bleed Your Brakes the Right Way for an Electric Bike

As summer rolls around, many e-bike riders will want to tune up their bikes and make sure they’re ready to ride once the weather turns nice. Checking your bike’s tires, making sure your battery is fully charged, and checking your brakes are all essential electric bike maintenance you should do before you ride but one that many often miss is performing a brake bleed.

When Do I Need to Bleed my Brakes?

One of the most common issues e-bike riders run into is the need for a brake bleed. The telltale sign of needing a brake bleed is pressing on your brake and having it feel “squishy”, “spongy”, or not having it engage at all.

What is a Brake Bleed?

Hydraulic brakes have a hydraulic line filled with mineral oil running from the brake lever to the brake caliper.  Using the electric bike brakes frequently while riding downhill can warm up this fluid especially at the caliper, and changes in weather can then make the hydraulic fluid colder or hotter while the e-bike is in storage.  These temperature fluctuations over the year can very slowly allow gasses dissolved in the fluid to form tiny bubbles.  Since gas is compressible, you will notice that the brakes of your electric bike don’t feel as firm anymore and the lever will travel closer to the grip before the brakes engage.

How Do I Bleed my Brakes?

This can be fixed at most bike shops with a brake bleed.  This involves attaching a syringe full of new mineral oil to the brake caliper, and drawing the fluid through the line up to the brake lever where an empty syringe is attached.  This service can vary in price depending on location, but every REI across the US can do this for about $25 per brake.  It is recommended to have this done once a year before you plan to start riding more.

Do I Need A Professional to Bleed my Brakes?

We highly recommend having this done professionally as it requires specialized tools and a bike stand.  If you wish to do this yourself though, you can use the red Shimano mineral oil and this bleed kit compatible with Zoom brakes:

If you think you may need a brake bleed on your Espin electric bike, reach out to us at hello@espinbikes.com and we’ll walk you through the steps of repairing your bike’s brakes!