In this next feature of our MTB How To, we will be going over how to bleed Shimano brakes properly. Bleeding your brakes is a regular maintenance service, necessary to ensure that your brakes are stopping like they should keep you safe out on the trails. Over time, brake pads wear down, mineral oil can deteriorate, and air can be introduced into the brake system. Here we will be going into detail on a complete bleed for any Shimano hydraulic disc brakes.
The brakes being serviced here are Shimano Saint 4 piston downhill hydraulic disk brakes. These brakes are strong and are Shimano's ultimate stopping power brake set for mountain bikes. The methods for bleeding both the front and rear brakes are the same.
Everyone has different tricks to bleeding their mountain bike brake system, and this is how we recommend bleeding all Shimano brakes specifically. To start, we are going to go over what tools are necessary to get the job done correctly. Without the proper tools, bleeding the brakes may not be safe and could cause them to malfunction on the trail. Bring your bike to a bike shop if you don't have the correct tools.
Most importantly, you will need Shimano Mineral Oil. Other brake manufacturers use either DOT brake fluid or other mineral oil. Mineral oil is a bit of a general term and it is very important to use Shimano specific mineral oil for all Shimano brakes. Using other types of fluid will breakdown the seals inside the brake system and could cause the system to fail.
Secondly, you will need a Shimano Bleed Kit. Most Shimano bleed kits include the bleed cup, oil catch bottle, and syringe. Here we will not be using a syringe so you don't push any dirty fluid up through the brake lever.
You will also need a Shimano bleed block to keep the brake caliper pistons spread apart throughout the bleeding process. Lastly, you will need a Phillips head screwdriver, a 7mm wrench, and a good set of Allen keys.