Bleeding your MTB hydraulic brakes

Wheels of Happiness

Rizal Philippines

April 5,2021

You need to bleed (purge the hydraulic fluid - mineral or DOT) when:   1.  it is not working properly -  the brake is weak, 2.   when you cut the brake line,   3.  it has been unserviced for a while and the fluid looks dirty.

There are 3 methods I know:

1.  Without the tools  taught to me by Vitul of Villamayor.    You add fluid to the reservoir to the brim and keep pumping  and watch the bubble come out.

2.  With the bleeder kit:

     1.  The syringe method   -  you inject fluid from the bottom at the caliper and watch the bubbles

           come out from the funnel installed at the top

     2.  Gravity method  -  you fill the funnel, open the bleeder at the bottom to empty at an empty                       plastic bag  and watch the color of the fluid change.  This method needs a lot of fluid

          fluid

     3.  Combination    - start with removal of air by pumping with the syringe at the bottom.  When done

          you remove the dirty fluid  by gravity.