Any rider who hits the trails on a regular basis will have had to replace their brake pads at some point - the more you ride, the faster they wear out! If you haven't done the job yet, you're in luck. Today's Tech Tuesday takes a closer look at replacing the pads in a Shimano brake system.
Inside you'll find some pointers to make the job easier, as well as a video guiding you through the process.
Along with your drivetrain and tires, your bike's brake pads are considered to be a consumable item. That is, they wear out while doing their job and require replacement over time. If allowed to wear too thin or even completely out, you will not only end up with a bigger repair bill that could also include rotors, but you're also putting yourself in danger. Some riders put off replacing their brake pads so long that they end up using the backing plate as pad material, and once that happens it can take only a few minutes of use to completely destroy a rotor. I've personally witnessed rotors being worn so thin from this that they fail catastrophically, folding in half in the blink of an eye and instantly pitching the rider. Scared yet? Long story short, inspect your brake pads often and replace when necessary for better performance, to save yourself money in the long run, and to prevent injury. Keep reading to get the lowdown on how to do this repair job.
Some pointers before you begin...
You'll need to remove the reservoir cover when installing the new pads, but you shouldn't have to perform a full bleed. Have a rag handy to catch any drips that happen while you work on your bike and be sure to not get any fluid on the new pads or rotor.
• As mentioned above, don't do anything half-assed when working on your brakes. Take your time and do it right, and if you don't feel up to it, get your local shop to do the job for you.
• It is always recommended that you have a clean work area when doing any brake work. Accidentally putting your new pads face down onto a dirty counter can ruin them. Save yourself time and money by doing a quick clean of your bench before you start.
• Never ever use anything metal, such as a screwdriver or hex key, to push the pistons back into the caliper. Doing so can damage the pistons by scratching the sealing surface and you will have to replace them.
• Use a rag and some isopropyl alcohol to clean the caliper before, and especially after, you replace the pads. This will greatly lessen the chance of you contaminating the new pads.
• Once you have the threaded pin and snap ring removed, put them somewhere safe where they won't get knocked off the counter. A magnetic bowl may seem a bit extravagant, but it is perfect for keep small bits like these from going missing.
• Anytime I'm dealing with brake fluid, be it mineral oil as found in Shimano brakes or DOT fluid as some others use, I'm careful to keep it from getting on anything that it shouldn't be on. To that end I will be sure to put a clean rag over the rotor and caliper that I'm not working on, something that is especially important on a system that may overflow at the master cylinder when changing pads. It is also good practice to put the removed wheel in a safe spot, not leaned up on the repair stand under your bike...
• Some people like to leave the old pads in place while pushing the pistons back as it protects the pistons from damage. This is certainly an option, but there is a good chance that this will render those old pads completely useless. Why does that matter? I like to keep my old pads for spares just in case I'm on the road and find myself needing to use them.
• Inspect the old pads for signs of uneven wear. Pads that are worn on an angle are a sure sign of a misaligned caliper.
Looking for a bit of help? Check out the technical documents
on Shimano's website
for more information.When do you replace your pads?
Shimano recommends not letting the pad's braking material wear thinner than 0.9 mm, but it certainly doesn't hurt to replace them sooner than that. My personal rule is to not let the pads get any thinner than the thickness than a dime. You'll also know that they have worn much too thin once the silver pad spring starts making contact with the rotor. If that is happening you know that you should have replaced the pads awhile back!
What's needed: 3 mm hex key
You'll need a plastic tire lever, some hex keys, a small phillips screwdriver, a clean rag, and the red Shimano pad spacer.
, plastic tire lever, small phillips screwdriver
, clean rag, isopropyl alcohol, the red Shimano pad spacer, and of course your new pads as well.Watch the video to see how to change the pads on your Shimano brakes: