Garage Files: How To Capture That New Brake Feeling Again
The step-by-step brake refresh
Brakes can be a real drag, literally. Over time, the hydraulic pistons that were once snappy and responsive can become sticky and sluggish, resulting in everything from noise to brake drag to uneven pad wear. If you’re one of the millions of riders who has suffered from this condition, we can offer some help. There is a quick and easy procedure that can breathe new life into those tired old stoppers, and it doesn’t even require a bleed, any special tools or even much time. It’s called the “brake reset.” This, according to the Shimano multi-service crew, is the most common repair they do for riders and racers when they’re at an event. We can teach you how to do it by yourself.
• 5-millimeter Allen wrench
• 3-millimeter Allen wrench
• Plastic tire lever
• Isopropyl alcohol
• Handful of Q-tips
• Brake-pad spacing chip (specific to your make/model of brake)
• Rotor truing tool, or crescent wrench in a pinch
• Shimano mineral oil (if working on Shimano brakes)
1-If you have a repair stand, start by putting your bike in with the drivetrain facing in. Normally, this is the wrong way to put the bike in a repair stand; however, if you’re only working on the brakes, this orientation allows much easier access to them.
3-Remove the retainer pin, pads and H-spring from the caliper. This Shimano XT brake required a 3-millimeter Allen to remove the retainer pin.
5-Pumping the lever will expose one piston slightly. Do not pump too much, as the piston can be pushed out too far. Three to five millimeters exposed should be perfect for most brakes. With the one piston now exposed, it’s time to clean the surfaces that seal the brake from brake dust, dirt, grime and debris.
8-With the inside and outside of the brake now clean, it’s time to lubricate the piston surface. With Shimano brakes, you should use Shimano-brand mineral oil. Just a couple of drops applied directly on the exposed piston is perfect. Never use any lubricant that’s not specified by the manufacturer for this. Shimano recommends using a few drops of their mineral oil, while other manufacturers recommend continuing to move the pistons and allowing the system to lubricate itself. Using lubricants other than those specified, such as chain lube or fork oil, will cause seal problems, pad contamination and a host of other problems.
9-Use the plastic tirelever to push the clean piston back into place. Sometimes, using the body of the caliper for leverage with the tire lever can be useful. Then, repeat with the opposite-side piston. Extract the piston using the tire lever and pumping process, then clean with a fresh isopropyl-soaked Q-tip.
10-Once cleaned and lubed, check to see that the pistons are extending equally by pumping the brakes one to two times without the pads, wheel or rotor in. If they look like this, with an equal amount of piston showing after the couple of pumps, you’re ready to re-assemble.
12-Use the paper towel to thoroughly clean all the surfaces of the brake. We prefer this handy “flossing” tech- nique for cleaning the inside of the brake, which is likely coated with the lubricating oil you just applied.
14-Double-check that all surfaces in and around the brake caliper are clean. Frames and brake adapters love to hide small pools of fluids that can instantly contaminate pads. Once everything is clean, it’s time to reinstall the pads.
17-Most brake manufacturers make a plastic pad spacer chip that’s designed to perfectly space the pads before the rotor is installed. These typically come with new brakes, but can also be found at the local bike shop. Ask your favorite shop mechanic for one for your model of brake and add it to your toolbox.
22-With the brake applied, tighten the caliper mounting bolts. It’s helpful to alternate between the two bolts as you’re tightening them. Tighten the first bolt about halfway, then the other, then finish torquing the first, then the second. This prevents the caliper from moving while the bolts are being tightened.
23-If the squeeze-and-tighten method doesn’t work, use the window on top of the brake to check the alignment of the brake and the trueness of the rotors. You should be able to see a bit of daylight between both sides of the rotor and the pads. Spin the wheel to ensure this is true all the way around the rotor.
24-If your rotor is slightly off—and most are—you can use a rotor truing tool, like this one from Wolf Tooth Components, to bring it back to true. Gently work the rotor in the direction it needs to go. This can also be done with a small crescent wrench—just be sure it’s free of contaminants before throwing it on the rotor.
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