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DISK BRAKE SYSTEM FUNDAMENTALS
Hydraulic theory: liquid cannot be compressed, only displaced. Therefore, force can be
amplified and carried through fluids by application of force to surface in a sealed system.
1 Cap
8 Plunger
2 Gasket
9 Tension Spring
3 Fluid Journal 10 Fluid Outlet
4 Dust Boot 11 Return Port
5 Circlip
12 Reservoir
6 Seal
7 Plunger Shaft
As the front brake lever is pulled, it forces the plunger through the master cylinder
reservoir, applying force to the brake fluid. The fluid is then displaced through the brake
line and into the caliper. The fluid then forces the caliper’s two pistons outward, creating
a pressure tension between the brake pads and rotor. When the brake lever is released, a
return spring acts to bring the plunger back to its original position, creating a suction
effect, bringing the fluid back to the reservoir and consequently sucking the caliper
pistons back to their original positions. NOTE: hydraulic theory only works properly in a
properly sealed and bled system. Air cannot be present, or the system will fail.
