Replace worn pads
Ten easy steps to restoring your bike’s stopping power
It’s all about friction 1
Your brakes work as hydraulic pressure forces the pads against the rotating disc(s). Each pad bears a layer of friction material which does the hard work. How rapidily it wears depends on how aggressively you use the stoppers. Let them wear too much and you’ll end up with the metal backing of the pad scraping the disc. And that’s very bad news.
Check new against old 3
Remove the pad retaining pin. Make a note of how any spring plates are mounted as these keep the pads tensioned and prevent rattling. When the pin has been removed, the pads will fall out. Inspect the pads for condition and compare them to the new ones, essentially double-checking that the replacements are exactly the same shape as the originals.
Do one caliper at a time 2
If you have a twin-disc set-up, work on one brake caliper at a time and keep the other mounted on the disc. With both calipers removed you run the risk of running out of brake fluid in the reservoir if the pistons are pumped out too far with no disc to bite on. Loosen the pad retaining pin first and then undo the caliper mounting bolts.
Time for a clean-up 4
Fill a bucket with warm water and add in a bit of bike cleaner. Moisten the caliper with water and then spray on some cleaner and allow it to soak in for a minute or so. The cleaner will penetrate and loosen dirt and contamination. Be accurate when spraying cleaner on the brake caliper, as you don’t need to be overspraying on to the brake discs and fork legs.
Get in there with a brush 5
Agitate the cleaner using a nylon brush and pay attention to the areas in-between the pistons. For seriously hard-to-shift muck, use a Scotchbrite pad with bike cleaner. Try to clean the exposed area of the pistons then give it all a thorough rinse. Finally, dry off with a clean cloth.
Fit the new pads 7
It sounds obvious, but make sure the friction material is facing the right way. The metal backing plate always sits against the piston. You will need to refit the spring plate and it will need a bit of tension or pressure as you install the retaining pin. Screw the retaining pin firmly making sure the new pads are positioned so they are flush against the caliper pistons.
Torque it up and check it over 9
Fit the caliper, making sure the disc slots between the pads. Install the mounting bolts and do them up evenly and lightly tighten. Use a torque wrench to make sure they are done up to the setting in your manual. Check the pad-retaining bolt as this might have a final torque figure too. Now ensure the hoses are still routed correctly and haven’t been disturbed.
Push back the pistons 6
Gently push the pistons back into the caliper. Do this by temporarily refitting the old pads and then insert a meaty screwdriver or tyre lever in between them and gently apply sustained pressure. The pistons will slowly retreat – they need to go back so they are flush with the caliper body.
Give the disc a proper clean 8
Before installing the caliper, use a brake cleaner to clean the disc. Most discs have two parts: the carrier in the middle and the disc surface where the pads contact. Clean the carrier first using brake cleaner and always wipe with clean workshop paper towel. Clean the outer last using fresh paper and brake cleaner, use a rotating motion until it is wiped clean.
Remember to pump it up 10
Pump the lever several times so that the pistons push the new pads and contact the disc, when they do this the lever will be firm. Do not attempt to ride the bike before pumping the lever. If you have a twin-disc layout, you can now repeat the fitting procedure on the other caliper. Do a visual check on the brake fluid. Brake gently at first to allow the new pads to bed in.