So you like to ride, and at times I'm sure you like to crack the throttle. I know I do. Something about getting out on the open road and opening the bike up a little. The raw power, noise, and acceleration, there's nothing like it. Along with the need for speed comes the need...

to stop. The worst feeling you can ever have is hitting those brakes and nothing happens. There is a sudden onset of panic like no other. Another scary feeling is your brakes locking up unexpectedly and going into an unstoppable skid or slide. In either case the bike will not stop anywhere close to the distance you initially expected it to. We seem to take brakes for granted thinking they are always going to work. The truth of the matter is that brakes are a hydraulic and mechanical device designed to undermine the laws of physics. Because of this they do need to be checked regularly and serviced when needed.

There are two different brake types found on bikes. Drum brakes, and disk brakes. Drum brakes are found on older bikes and occasionally on the rear of a newer bike. This type of brake is less efficient and needs to be adjusted to keep them working correctly. Disk brakes are very efficient meaning shorter braking distances and are self adjusting. Disk brakes are found on the front of almost all bikes built in the later half of the 20th century and on the rear of all the newer bikes. 
Some bikes come with dual disk brakes providing excellent stopping power.

Each brake type is made up of a few components performing a few basic functions. There is a lever or pedal connected to a master cylinder which when activated forces brake fluid through all of the brake lines. This fluid travels to the wheel cylinder in a drum brake or the caliper in a disk brake. As the fluid enters either one of those components it forces one or more pistons out of the bore of these components. The pistons then push the friction material into a metal drum or disk. This clamping down on a disk or pushing out against on a drum causes contact of the two surfaces creating friction and drag. On some older drum brake systems instead of hydraulic it is all mechanical utilizing linkages and fulcrums. Either way the principle is the same.

There are three things you need to pay the closest attention to. The amount of material on the friction components known as the pads or shoes, check the fluid for level and quality, and make sure there are no leaks. The other components should be checked when servicing the system. At that point the system will be apart and it will be easy to determine if the components are functioning as intended or worn. The condition of the pads or shoes will also be an indicator if there are concerns with other components.

Pads or shoes are the friction component. They are also the item that will be replaced due to wear most frequently. The thickness of a pad or shoe varies from bike to bike when they are new. The minimum thickness any pad or shoe should get is 1.5 mm or 2/32”. If you let them get any more worn than that you are chancing them crumbling apart and or going metal to metal as they call it. Which means the backing plate of the shoe or pad will contact the drum or rotor causing severe damage and the need for replacement, cha ching. So replace them before you have that problem. Replacing the pads is an easy thing to do. Just follow the manual, pay attention, and take your time. If the pads are worn unevenly than you want to look at the caliper for improper operation. The pad could tell you that either the area with little wear is not applying or the area with a lot of wear is staying applied. If you notice a glazed surface on the pad it might be an indication that the brakes are dragging or that you are just too hard on them. 

Brake fluid is the blood of the brake system. There has to be enough there and it has to be in good condition. The fluid is what is used to apply the brake. It is a liquid that has to apply high pressure. It can’t compress and it has to be able to withstand very high temperatures without boiling. It is because of the high temperatures and the fact that brake fluid absorbs moisture naturally that the fluid breaks down over time. This is why it is important to flush out and change the fluid. Some recommend replacing the fluid every year some say every two years. I feel it is too difficult to put a set limit. Some people ride a lot, some a little. I say look at the color. When it begins to turn dark or more towards a brown color it is time to change it, however I wouldn't let it go more than 3 years. If you haven't changed the fluid in some time you will be amazed at the difference in the feel of your brakes when you do change it. When it comes to fluid and its job we also want to make sure there are no leaks. We want the fluid to be able to get to where we want it to go. The brake hoses need to be in good shape. You don't want weak hoses that balloon out when the pressure in the system increases, that will prevent the pressure acting where we want it to giving a spongy feel to the brakes. It is stated that installing steel braided lines on your bike will increase the performance of your brakes by roughly 50%. I don't know about the 50% but steel braided lines are much less prone to ballooning than rubber hoses which will concentrate all the brake fluid pressure into driving the friction material in contact with the rotor. Besides they look good too.

The caliper of a brake system is the component that houses the pads. The rotor spins in between the caliper and pads. When you apply the brake, fluid rushes into the caliper pushing out pistons, which in turn force the pads into the rotor. When you let the brake go the fluid then rushes back towards the master cylinder which takes the pressure off of the piston and allows the rubber seals around the pistons to roll back and return the piston back. On single piston designs the caliper is mounted with bolts that act as a slide for the caliper to move on allowing the inner pad when it contacts the rotor to pull the outer pad into the rotor. These slides must move freely for the brake to apply evenly. Otherwise one pad might never apply or always drag. On multiple piston set ups there are pistons on both sides so the caliper does not have to move at all. However the seals around the pistons can swell due to poor fluid quality or contamination of the fluid. This will cause the piston or pistons to not apply or more commonly to not release. So again by looking at the pad you can determine if there is a problem with the caliper. You will be able to determine if the caliper is applying evenly, if it is staying applied, or if it is not applying at all. If you experience any of these concerns you will have to replace the caliper.

Bleeding the brake system is an art and it seems everyone has their own trick. I prefer a vacuum bleeder and the old fashioned pump the pedal and open the bleeder. No matter how you do it the trick is to get all the air out of the hydraulic system to provide a firm pedal or lever. Any time you replace a hydraulic component or open the hydraulic system up you will have to bleed the brakes. If you are interested in some different methods or if you have any questions on anything you can email Joe or Dan and we would be happy to share our tricks and or information.

Keep in mind that if you decide to perform any service on your brake system, that when you finish you check the brakes and pump them before going on the road. When you do take it out make a few low speed stops first to be sure they feel correct. If you ever have to adjust brakes remember not to adjust too tight. Keep in mind that as the brakes heat up everything expands a little. The brakes will also grab a little better as you ride. Always check your work and then check it again. Trust me it is worth the effort. I’ve seen even the most experienced do a brake service and then end up in an unwanted situation. I saw a friend in a rush forget to pump the brakes up after changing the pads. He jumped on the bike to road test it around the block. When he took off down the street and got to the intersection, the brake lights came on but he just kept on going. Had to do the laundry after that.  

When the bike is designed the brake system and components are engineered to provide the proper amounts of braking power for the weight of the bike and the suspension geometry. Changing these components with aftermarket parts can greatly affect the characteristics and quality of braking for the better or for worse. So research and care should be taken before changing any of these components. Always do your homework and refer to manuals. Never assume or guess it can be fatal.