You’ve gone and re-centered your brakes based on my past article, how to re-centre your brakes, but that didn’t help? The good news is that there is no wildlife to be found within three kilometres of you, due to the noise your brakes are making. The bad news is you can’t stop your bike on the spot.
If your brakes are squealing and have lost their ability to stop you, there is a good chance the brake pads are worn. To fix this, let’s start by checking your pads and then replacing them if worn. Put your bike on a work stand and remove both wheels. Look at your brakes. The pads will be held in place by a lock mechanism and you will need to remove this to get at the pads. This might be a pin (Shimanos, and some Formulas brakes have a pin), or a spring clip (Avids), or a magnet (Techtro), or a little spring clip like the Hayes shown in our photos. Start by taking out the pin with a 3mm Allen key or a flat bladed screw driver. Now remove the pads. Typically these come out from the bottom of the brake, but some come out the reverse way. Bottom line, please remove them. If you can’t get the pads out, have a unique brake system, or just find swapping out brake pads above what you should be doing to a bike, please take them to a local bike store. The charge for brake pad replacement is around $10-20, plus the cost of new pads.
Now that the pads are out, take a look at them. To give you an example of what you’re looking for, refer to the photo below. The pads on the left are new, the middle are used and almost dead, and the right ones have uneven wear. If the pads are less than 2 mm thick, I would replace them (middle pads shown in phot). Yes, you might still get some life out of them, but one good day of riding in wet weather and you will burn right through them. I would keep them as spares if you want. If the pads you’re looking at have uneven wear, file them flat and check the spacers on the brake calliper bolts or the rotor to find out why they are wearing uneven. If you cannot figure it out, maybe it’s time to take your bike to a shop. The middle pads in our photo are wearing more on one side than the other. This is typically a sign that the pistons are sticking a bit. Definitely get your local mechanic to check this out for you.
Now look at the pistons, they are the mechanism that pushes the brake pads into the rotor, see how the upper (inside on the bike) piston is in 3 mm and the lower (outer) one is only poking out 1mm. Odds are the outer piston needs to be cleaned and re-lubed. You can also see the pin that the brake pad spring clip attaches to.
Assuming you are replacing the pads, put the OLD pads back in the brake caliper. Yes, the old ones. Then use a large, smooth, flat blade screwdriver to GENTLY push both pistons back into the calliper. I find a big downhill tire lever is great for this. You are using the old pads to push against so you do not damage your new pads or the brake. Once both pistons are pushed in all the way, remove the old pads, throw them out, and put the new pads back in. Do this for both brakes (front and back).
Now put your wheels back on and re-center the brake; see how to re-centre your brakes.
Your new pads will need a bit of time to break in; find a small hill and gently pump the brakes on and off while coasting down the hill. This should adjust the pads and stop the noise. If this still has not stopped the horrible squealing, try a different rotor, or just turn up the music in your ear buds.
Article by Dave Williams. Dave is a “wrench” for hire living in Banff, Alberta. He has provided bike support to riders participating in events including the TransRockies, 24 hours of Adrenaline, Sea to Summit, Full Moon and Raid the North. To get in touch with Dave, drop him a line at dave_williams[at]shaw.ca