How to bleed Shimano road hydraulic disc brakes

If you’re bleeding the front brake, put the bike in a work stand angled slightly down to stop the forks from moving around. When you’re working on the rear brake, angle the bike upwards to help with bubble flow and use a strap or similar to secure the bars. We’ll just concentrate on the front wheel for now though.

Remove your front wheel, then reset the pistons by pushing them gently back into the calliper with a pad spacer tool or a big, flat screwdriver. You don’t want to go in too hard and gouge the brake pads as you can easily damage them.

With the pistons reset, remove the brake pads to stop them getting ruined by any spilt fluid. First remove the little clip on the right-hand side and then undo the retaining pin with the flathead screwdriver.

Insert your bleed block into the calliper to hold the pistons in place. Secure it with the retaining pin that usually holds the brake pads.

Peel back the shifter hood. Before you open up the hydraulic system, protect your hands by putting on some gloves, and protect your hoods by placing a rag around the port to catch any spills.

Undo the bleed port screw on the top of the shifter body. It’s quite easy to round these out, so ensure to use a good quality, undamaged Allen key. Make sure you keep the bleed port screw somewhere safe.

For most Shimano brakes, before you can fit the fluid reservoir, you’ll need to fit a small adaptor. Screw it into the top of the bleed port. Once that’s fitted, take the fluid reservoir from your bleed kit and screw it into the top of the adapter.

Half-fill the syringe in your bleed kit with the hydraulic mineral fluid, then take the little rubber dust cover off the bleed port on the brake calliper. Push the syringe hose onto it, and lock it into place with the collar.

Use your 7mm spanner to undo the calliper bleed port a quarter of a turn.

Before you depress the syringe, remove the stopper from the reservoir.

Gently depress the syringe to push the fluid through the system. Don’t push too hard as this can cause it to leak. You should see air bubbles coming out of the system and into the reservoir. Continue to push fresh fluid through until the bubbles stop or you only have 10ml or so left in the syringe.

Tighten the calliper bleed port with the 7mm spanner. Then, pull back slightly on the syringe plunger while removing it to reduce spillage. Clean up any oil with a rag or paper towel – any remaining oil could contaminate the the pads.

Now stick the syringe hose carefully into the fluid reservoir at the lever end and see if you can suck any stubborn bubbles out of the system from the top end. Once you’ve sucked any final bubbles out of the system, remove the syringe, and plug the fluid reservoir with the plug pin.

With the plunger in the reservoir, unscrew it from the bleed port and place it to one side. Then, replace the bleed port bolt. Clean up any spilt fluid, then fold the hood back into place.

Remove the piston spacer and refit the pads. Slide them into place and screw in the retaining pin. Make sure to put the safety clip on the end of the retaining pin.

Attach the front wheel to the bike. If you don't have a thru-axle, it's wise to put the bike on the ground to make sure the wheel is centred in the dropouts.

Loosen the calliper bolts slightly, just so the calliper can move around on the frame. Then, pull the brake, and tighen the calliper bolts as you hold the brake closed. This should centre the calliper around the disc.