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It’s a real hassle when you’re electric bike brakes suddenly stop working! However, there is good news – electric bike brakes can almost always be fixed, either by a bike mechanic or by yourself if you’re confident enough.
You just need to know:
- What the problem is
- What to do about it
I’ve ridden electric bikes for years, and I now know that there are 9 common reasons why electric bike brakes stop working.
In this post, I’ll take a look at what each of these reasons is, and the best way to fix each one.
1. Your Brake Lever Is Damaged
This is a very common issue.
Brake levers can be quite prone to wear and tear over time, especially if you often use your electric bike. Damages in brake levers are often caused by the following:
- Your electric bike falls over or gets knocked down often
- The brakes are worn-out due to too much pressure
- Prolonged or excessive use
The best way to go about a damaged brake lever is by entirely replacing it. It may seem tricky to do at first glance, but it’s actually quite simple.
To get started:
- Unscrew the brake line from the brake lever to separate the two parts.
- Unscrew the washer from the brake line to pull it from the screw’s center slit.
- Unplug the e-brake (if it has one) before removing the brake lever.
- Remove the grip from the handlebar by using a flathead screwdriver.
- Loosen the screw of the brake lever to remove it, then replace it with a new one.
If you don’t want to go through the trouble of doing it yourself, you can also take your electric bike to a professional to have them replace it for you.
2. Your Brake Pads Are Worn Out
Brake pads are essential to slowing down and stopping your bike. If these pads are worn out, they won’t be able to make proper contact with the steel disc on the bike’s wheels.
Brake pads are often worn out faster by riding consistently in muddy, aggressive, or wet terrain. (Source)
When your brake pads seem worn out, it’s best to go ahead and replace them. You can do this on your own as long as you have some pliers, a 3 mm wrench, and a 5 mm wrench.
To replace your brake pads:
- Unscrew the caliper bolts and remove the adapter.
- Remove the cotter pin by bending it straight, using needle-nose pliers.
- Push the pads out from one side, then pinch and pull from the other.
- Grab your new brake pads and insert them by pinching the pads together.
- Insert the cotter pin back and bend it at a 90° angle to lock it in place.
- Mesh the pads to the rotor.
- Screw the bolts back together with the adapter.
If you’d like to see how to change brake pads in video form, I found this excellent Youtube video from Evolutionary Tom on this subject. He is adamant that you don’t need a professional and you can address this issue yourself:
One of the common reasons why electric bike brakes fail is due to out-of-place cables. You’ll notice that your cables need adjustment if you have to squeeze extra hard to slow down.
- Calibrate your barrel adjusters by turning them clockwise (for tightening) or counterclockwise (for loosening).
- Squeeze the brake lever to check if it feels right.
- Keep calibrating the barrel adjusters until the brake lever feels accurate.
4. Your Brake Levers Are Jammed
A jammed brake lever is often a result of issues relating to tension and resistance.
Since brake levers don’t have any spring to bounce them back, they rely on the tension produced by the caliper’s cable.
If there’s resistance in this cable, the levers will most likely get stuck. This is usually caused by:
- There’s damage in the cable that links the levers to the caliper
- The cable is too short or misaligned
- Your caliper lacks spring tension
- The electric bike’s cable housing is dirty or damaged
- The brake lever is grimy
Since jammed brake levers can have many different causes, it’s best to bring your electric bike to a bicycle mechanic. The issue can be tricky to rule out and may take a while to check.
With a professional’s help, you can quickly diagnose the problem, apply the best solution, and check for any necessary fine-tuning.
5. Your Brake Pads Are Oily or Contaminated
This is one of the easier issues on this list to be able to check for.
If you’ve passed by an oily road or terrain, chances are your brake pads have already become contaminated. The same can be said if the bike’s suspension or brakes had some fluid leak.
You’ll usually have an inkling that this has happened.
You can determine this by a simple visual check on your brake caliper or rotor. Your brake pads are most likely contaminated if you see an oily film around those areas.
Luckily, contaminated brake pads aren’t too difficult to deal with. The burning method is one of the best ways to rid oil and other impurities from your brake pads.
To do this:
- Place your brake pads on a fire-resistant surface.
- Be sure that there are no fire hazards nearby.
- Drip a bit of 70% (or more) isopropyl alcohol on the pads.
- Light each pad on fire and wait until the flame completely burns off.
6. Your Brake Rotors Are Damaged or Dirty
This is another common issue, and one that is simple to check for.
Brake rotors are also prone to damage and dirt buildup with prolonged use. Other than when your brakes aren’t functioning properly, you’ll know the rotors are damaged or dirty if you hear rubbing noises whenever you bike.
As for dirt buildup, road grime and dust can accumulate when you don’t regularly clean your bike. It can rust over time, too, in case you bike or live in locations where there’s high humidity.
Refer to the table below for the appropriate solution, depending on the root issue:
|Dirty rotors||Clean the rotors using a degreasing wash, bike-specific degreaser, or alcohol.|
|Bent rotors||In case some parts of the rotors are bent but are still in good condition, use a truing fork to bend them back in place.|
|Severely damaged rotors||If the rotors are too old and seem beyond repair, it’s best to replace them.|
Disc brakes play a vital role in ensuring your electric bike’s brake strength and consistency.
Yes, your brakes can still work even if the disc brakes aren’t bedded in, but they won’t be as effective as they’re supposed to be.
There are two ways you can bed in your disc brakes. You can either ride your electric bike on an open area with slopes or a flat surface.
If you’re in an open area with slopes:
- Ride the bike at normal speed.
- Gradually decrease to walking speed.
- Be sure that you don’t completely lock the brakes when slowing down.
- Get as many slowing sections until you reach the bottom of the slope.
- At the bottom, turn your back in the opposite direction without stopping completely.
The steps are similar for flat surfaces, except you need to add some clean water to the rotors. They should be good to go after five to ten laps.
If you want to watch a video on how to bed in disc brakes, this brilliant video from Park Tool is a good choice:
8. Your Caliper Is Loose or Misaligned
Your electric bike’s brakes won’t be able to do their job if your caliper is loose or misaligned. The pistons that push the brake pads won’t hit the brake disc as they should unless your caliper is secured.
You can easily determine if the caliper is misaligned when you inspect your caliper. Look to see if the caliper is centered on the rotor or not.
To adjust your caliper’s position:
- Loosen the bolts holding the caliper to the frame, without completely removing them.
- Once they’re slightly loose, squeeze and hold the brake lever to align the caliper.
- While holding on to the lever, re-tighten the bolts.
- You can also visually align the caliper without holding the brake lever.
9. Your Electric Bike’s Brakes Have Air Bubbles
If you have a hydraulic brake system, one of the threats to its functionality is having air bubbles. You’ll notice this if the brakes of your electric bike are too stiff to use.
Bleeding your electric bike can be a bit tricky, but if you’re up to the task, just follow the steps below.
- Unwind your lever’s bite point and reach adjustments.
- Set your brake lever until the reservoir is under the bleed port.
- Remove the brake pads and temporarily replace them with a bleed block.
- Use a syringe and fill it with hydraulic bike fluid, then attach it to the caliper and brake lever.
- Let the bike bleed by squeezing the lever to remove air bubbles.
- Secure all the bolts and adjustments back.
Faulty electric bike brakes can prove troublesome. Not only does it disrupt your daily biking activities, but it also puts you at risk of accidents.
Luckily, if you’re confident, you can sort out most issues yourself. If you’re unsure, it’s better to get the services of a mechanic (and for some issues, this is the best way to go for everyone.)