“Nobody cares how fast it goes if it doesn’t stop.” An old mechanic said this to me once to point out the importance of brakes. Brakes are one of the most important safety systems for motorized vehicles.
How often should you change your brake pads? Brake pads need to be changed every 20,000 miles to prevent the brake pads from completely breaking down. You should also change them if they are 1-2 millimeters or they are less than 1/8 of an inch. If you do not replace them, you could cause harm to yourself and other motorists, or you could create further damage to your bike.
Maintenance on your motorcycle’s braking system is a vital part of ensuring that your safety is not compromised. Fortunately, there are ways to check your brakes and perform repairs and this article will dive into how to do so. This article will teach you the ins and outs of brake pads and how to change them.
How Often Should You Change Your Brake Pads?
The interval for changing brake pads depends on a few things, but a good range is to change every 20,000 miles. Brake pads can last a long time under normal riding conditions and can go even longer under light braking applications. To make sure they aren’t wearing out too quickly, it is wise to keep a record of any repairs made in order to track the lifespan of your brakes.
Another meter by which to measure the life of your brake pads is the pad thickness. The initial thickness will depend on the type of pad used. Once the pads get worn down to 1-2 millimeters or less than ⅛ of an inch, it’s probably time to replace them.
Brake pads don’t really have a shelf life, meaning they don’t necessarily go bad if they aren’t getting used. If you don’t do a ton of miles per year, there is no need to worry about replacing them after a certain amount of time. Do a quick inspection of the brakes before a ride to make sure everything is good. Now, having said all this, if you are restoring a rusty bike and it hasn’t been driven since Ronald Reagan was in office, it is worthwhile to replace the pads just for the peace of mind.
Why Brake Pads Need To Be Changed
Changing out worn brake pads keeps the braking system functional, excluding any other issues. When pads are worn beyond their functional thickness, the braking ability becomes compromised leaving the rider and other motorists at risk. Being able to confidently control speed is critical in avoiding accidents.
Aside from the safety factor, letting your pads wear beyond the minimal thickness is a good way to spend a lot of money on repairs. There are a few things that could happen:
- The rotor will get eaten up
- Excess heat will cook your brake fluid
- These combined can ruin your calipers
Brake pads are constructed of a metal plate that has been punched into a shape that will fit into the caliper and a thick layer of friction material. The brake rotor is the metal ring that is connected to the wheel and rides between the brake pads. The friction material is formulated to turn the momentum of the moving vehicle into heat in a safe way. This material is designed to wear out in order to prolong the life of the rotor. When talking about the brake pad thickness, we are talking about the amount of friction material left on the pad.
Suppose all of the friction material has been worn away and now there is just the metal of the brake pad plate riding against the metal of the rotor. The friction of the metal-to-metal contact actually produces more friction, but only because the heat generated is almost enough to weld those two pieces together. At the same time, both pieces of metal are being chewed up and are no longer able to perform as designed.
Speaking of heat, brake fluid doesn’t like to be hot. If it gets hot enough to boil, the small amount of air in the fluid starts to expand. Since brake fluid is non-compressible and the air is, the hydraulic power of the brake fluid is now non-existent. Under this scenario, the fluid will likely need to be replaced.
If both of these conditions are present, you might as well say adios to your calipers, too. The brake calipers are the hydraulic cylinders that squeeze the pads against the rotor. Inside the caliper assembly are seals and other meltable components that will be ruined under excessive heat conditions. Rebuilding or replacing the calipers is more money added to your repair bill.
How To Fix These Issues
Making repairs to the components of the brake system requires a moderate level of skill. Most repairs are very doable, but may be a new challenge for those who haven’t done much wrenching. If you are interested in doing the work yourself, it is wise to have a repair manual to follow and to research the job you’re doing before digging in.
When replacing the rotor, pads, and/or calipers, you will need a way to prop the bike up in order to take the wheels off. There are bike stands and lifts available or there are ways to safely block up the bike using sturdy wood pieces. Use caution when doing so, as the bike can easily tip over and cause injury.
In preparation for any repairs, make sure to have the right tools. Here is a list of tools to have at the ready:
- Wrenches in a variety of sizes, including metric and standard sizes
- Socket wrench and sockets
- Rags and some brake parts cleaner
There are a few other specialized tools to find, as well. First of all, it should be mentioned that brake fluid is corrosive to paint and should be handled carefully. As such, have some clean rags, brake parts cleaner, and a method to collect brake fluid. A small plastic bowl or pan will work well to catch the old fluid. Next, it is a good idea to have a good-sized syringe for extracting brake fluid from the reservoir. Finally, some people will use a hand-operated vacuum pump for flushing and bleeding the system. These are usually available at Harbor Freight and other hardware stores or from Amazon or other online stores.
To begin, start by lifting the bike and propping it safely to be able to remove the wheel. Once removed, you can then replace the rotor as needed. Typically, there will be 5 or so bolts holding the rotor to the hub and a new rotor will come with new bolts.
Replacing the pads is decently straightforward. You will likely need to unbolt the caliper to be able to maneuver the pads out. This will not involve removing the wheel but refer to specifications for your specific bike. When installing the new pads, it’s a good idea to add a bit of brake grease on the back of the metal plate to reduce noise. Once the new pads are on, bolt the caliper back on, again following the specifications for your bike.
With the wheel still removed, you can access the pads and caliper, however, it is not always necessary when doing just pads and/or calipers. When replacing the caliper, there will typically only be a couple of bolts holding it to the fork or frame.
Before disconnecting the brake line, gently pinch the soft line to prevent all fluid from leaking out. Once the line is connected to the new caliper, you will need to bleed the system. This process allows brake fluid to get completely into the new caliper and force all air bubbles out. There are different methods of bleeding, but the essence is opening the bleeder valve to let air and fluid out. Once most air is out, make sure to pump the brake handle to ensure that it is working and feels right.
The process for bleeding the brake system is also used when flushing out the old fluid. This replaces old, dirty fluid with fresh brake fluid. This is often where the syringe and a bit of rubber hose will come in handy. Simply use the syringe to draw out old fluid from the reservoir and bleed out the lines. Then pour in new fluid and bleed out any air bubbles.
After making any repairs and before taking a ride, always make sure that the brake operates. Just because the damaged component is replaced does not guarantee it will work. After verifying that it works, take the bike for an easy ride and make several stops. This will burnish the brakes, which essentially sets the pad material to the minuscule imperfections in the rotor surface.
Brakes are critical to safely operating your bike. Having worn-out brake components pose a risk to your safety as well as to others. Regularly check for any worn parts and arrange to replace them. Most brake work isn’t difficult but can require a bit of skill and tools to do properly. Follow manufacturer specifications when making repairs and always verify the repair before riding.