How Can I Repair Bike Disc Brakes

They are pretty much becoming the norm on most new mountain bikes.  I’m talking bike disc brakes. Disc brakes have been around for some time but they are starting to become the brake of choice for the trails for one simple reason; they work well. Unfortunately though, if you do enough riding you may be forced to make some repairs to them. I just recently had to take a crash course on how to repair bike disc brakes due to a crash on the course (pun fully intended). It definitely got me thinking about how can I repair bike disc brakes once they have been damaged. What I learned was a simple yet very effective bike servicing technique, allowing me to get back out onto the trails once again in no time flat.

Problem – They Are Very Exposed!

Take a look at any bike with disc brakes (see picture below) and one thing should be very evident; the rotors (metal discs attached to your wheel’s hub) are pretty exposed and just waiting to get bent out of shape.

They Are Very Exposed

It is very easy (as I found out) to bend one and once bent, let the squealing begin. Disc brakes work by allowing small brake pads (that are concealed in a metal housing) to squeeze a metal rotor which is connected to your wheel, thereby slowing you down. Where the rotor enters the housing though, is a very tight fit. Any little bend in your rotor and you are going to be rubbing against your brake pads which is annoying but it also makes it tough to ride because your brakes are now partially on.

This situation is quite easy to fix for minor bends so let’s see how.

How Can I Repair Bike Disc Brakes and Put An End to the Squealing

The first thing you are going to have to do is remove the disc brake housing from your fork or frame (this procedure works for either the front brake or the back one). Simply remove the bolts using a hex key as shown.

Repair Bike Disc Brakes

Once the bolts are removed, your brake housing will simply lift off the frame. Now attach a zip tie to the area where the housing was bolted and use it as a depth gauge for your rotor. The picture below shows the zip tie in place ready to measure the distance of the entire circumference of the rotor.

Bike Disc Brakes

Slowly spin your tire and watch for a gap to appear between your tie and the rotor. As you spin your wheel, you will get a pretty clear picture as to where your rotor is bent out of alignment. Now that you know where these out of alignment areas are, simply take an adjustable wrench and slowly bend the rotor in those areas where it needs reshaping (see picture below).

Repair Bike Disc Brake

Do a few minor tweaks with the wrench and test the rotor clearance once again using the zip tie. You may need to do this bending technique numerous times but with patience, you should be able to get your rotor fairly straight once again.

Once the rotor is back in shape, simple remove the zip tie, reattach the brake housing using the bolts and test the clearance. There should be very little, if any, rubbing of your brakes with your rotor.

Congratulate Yourself On a Job Well Done

With the brakes repaired, there is really no excuse needed to get on out there and hit the trails to test them out. With the fixes complete, you have now answered the question for yourself of how can I repair bike disc brakes. This really is a simple technique to learn and if you do much riding, then the odds are pretty good that you may need to use it more than once. This shouldn’t be an issue for you because you now know what to do, right?

Robert Flaherty