As a motorcycle rider, if you have a penchant for riding ATVs, bikes, or wheeled Powersports machines, you will eventually have to bleed your brakes. Now, this is a part of your regular motorcycle maintenance routine, that the user manual suggests you perform once or twice a year.
Brake fluids must be replaced at regular intervals because they degrade with use and over time, which means that your motorcycle’s brake system might not work as well as it did when you first bought the bike. Brakes absorb water over time, thereby reducing the boiling point of the brake fluid. When you push the brake pedal, this water gets mixed with the brake fluid and cools down your motorcycle’s brakes – resulting in a spongy feeling when braking.
Brake bleeding is such an important procedure that it can help improve your motorcycle’s performance considerably.
Consequences of Not Bleeding Motorcycle Brakes
However, if the motorcycle’s brake fluid doesn’t get replaced and is allowed to degrade due to old age, it can affect your braking performance.
So, while you’re performing regular maintenance on your bike by replacing the brake oil every few months or so, you should also consider bleeding too. You can also suffer from poor control over your bike which is never good when on bumpy roads or when riding at high speeds.
Brake fluids are hygroscopic, meaning they soak up water from the air. The brake fluid absorbs moisture and causes corrosion on the metal and rubber components of your bike’s braking system. This includes the brake lines, master cylinders, rubber hoses, hydraulic cylinder pistons, etc. It can hamper the performance of your brakes drastically and cause them to fail when you need them the most.
Brake bleeding requires special tools and equipment, which most owners only use during emergencies or if their bikes malfunction due to some other reason.
However, despite its perceived difficulty, this process is rather easy to complete using the right tools and following a simple set of instructions.
Steps to Bleed Your Motorcycle Brakes
The basic steps to bleed your motorcycle brakes include:
Remove the Diaphragm and Cap
Before you start flushing fluid or removing bolts, take some time to wipe your brake lines, reservoir and calipers with a cloth. Wipe off any dirt or debris on the surface of these components. Remove the brake fluid cap and remove the rubber diaphragm (on most motorcycles).
There are several different types of brake designs on modern motorcycles, but usually, there is only one rubber diaphragm that covers the top portion of your reservoir. Motorcycles that have built-in reservoirs do not usually come with this component.
Ready the Caliper’s Bleed Nipple
Most motorcycle brakes have their own bleed nipples. You will need to pry off the aluminum caps (if any) over the brake fluid nipples on your brake calipers, using a screwdriver. Pump the brake lever a few times to push any air out of it.
Allow the lever to slide back and close the bolt of the bleeder. Keep an eye on the level of fluid in your reservoir, because it must not drop below the rubber diaphragm.
Top Up The Reservoir
Repeat the previous step on all of your brake calipers. It is very important to always top up the reservoir after bleeding each wheel since it might lose fluid while you flush out old and contaminated brake fluid from within the lines and caliper.
Refill it with some new fluid until you can see fresh clear liquid on the hose. Keep adding fluid until it reaches the brim of the reservoir. Do not overfill.
Now, take a piece of cloth and clean off any dirt from around your brake calipers, as well as from the bleed nipples on each caliper.
Tighten Bleeder Bolt and Clean Up
Now, it is time to tighten the bleeder bolt. Take a torque wrench and tighten this bolt.
You may also use a socket to tighten the bolt in case your motorcycle does not have a torque wrench. Lastly, replace the rubber diaphragm on top of your master cylinder’s reservoir. Do not forget to put the cap back on top of it after you complete these steps.
You can now go ahead and test out your brakes by applying pressure to your brake lever and stopping at the first sign of any resistance.
If you notice your brakes feeling spongy or completely unresponsive, then repeat these steps until you can feel the difference in performance. It usually takes about four separate bleeding sessions to start noticing improvements after completing this procedure correctly.
Bleeding your motorcycle brake fluid is an important procedure that should only be completed by qualified motorcycle mechanics, but you can do it yourself with ease by following the above steps.
It can help improve your braking ability considerably, and also allows you to get the most out of your brakes and brake fluid.