How to bleed your bike brakes27 July 2022
At some point, you may need to bleed your brakes, either down to a leak of fluid or just for general maintenance. Bleeding brakes are a little more advanced than most home maintenance, but with a little confidence and a few extra tools you can do it yourself.
First of all, you will need to find out what kind of fluid your brakes use, Shimano use Mineral Oil whereas SRAM use DOT 4 or 5.1 fluid.
You will need the correct type of bleed syringes for your brakes. The main manufacturers, SRAM and Shimano, make their own.
Below you will find a basic guide to bleeding SRAM brakes.
Before beginning check pads for wear, if they are worn now is a perfect time to replace them.
Start the bleed process by filling one syringe to 15ml and one to 5ml.
Clean the bike down and remove the front wheel, remove the brake pads and insert the bleed spacer in the calliper. We also like to wrap a little tissue roll around the calliper to stop any dribbles of fluid. Using a T10 remove the bleed port screw and Insert the syringe with 5ml of fluid into the calliper bleed port.
Next, pull the lever hood back to uncover the bleed port screw, remove the screw with a T10 and insert the syringe with 15ml into the bleed port. Again, you can wrap a little tissue roll around the hood to stop any dribbles.
Starting at the shifter, keep both syringes upright and push the fluid through to the calliper slowly, using about 10ml of the brake fluid as this will be enough to pass through the system and remove any air from the calliper. Repeat by pushing the fluid from the calliper back through to the lever. You may wish to do this step twice.
Remove the syringe from the calliper and re-insert the bleed port screw. Pull back on the lever syringe to drag any bubbles out through the hose, make sure to keep the syringe upright then press down on the syringe to pressurize the system.
Remove the lever syringe and reinstall the bleed port screw. Clean the lever and syringe using either brake cleaner or water, and reinstall brake pads.
Check brake alignment to be sure the pads aren't catching, if they are using a T25 loosen the brake calliper bolts and realign the calliper so the pads are not touching the rotor. Some people like to do this by sight whereas others like to press the brake a few times then whilst holding the brake on, re-tighten the calliper bolts.
Now your brake should be feeling firm and solid and be working perfectly, time to get out on the trails and have a good time.