Activating the brakes
When the brake pedal is pressed, primary hydraulic pressure is generated in the floating caliper chamber, causing the piston to move toward the brake disc. The moving piston contacts the inner brake pad, forcing the pad to move along the guide channels of the fixed support bracket and contact the inner side of the brake disc.
When the piston leaves the caliper chamber, it passes through an internal ring seal located in the caliper chamber. The movement of the piston causes the seal to deform, and therefore the seal applies pressure to the outer surface of the piston.
The floating caliper now reacts and begins to slide along the two bushed bolts in the opposite direction to the piston extension. The floating caliper contacts the outer brake pad, forcing the pad to move along the guide channels of the fixed support bracket and contact the outer side of the brake disc.
With both brake pads now in full contact with the brake disc and hydraulic pressure acting on the piston, no further movement of the piston and floating caliper is possible. The force exerted by the piston and caliper on the brake pads rapidly increases, squeezing the brake disc and slowing the vehicle.
Releasing the brakes
When the brake pedal is released, the hydraulic pressure in the caliper chamber drops and the force no longer acts on the brake pads. The brake pads move slightly outward under the force of the rotating brake disc, and the internal caliper seal returns to its normal shape. As the seal moves, it grips the outer surface of the piston and draws the piston into the chamber enough to provide the necessary clearance between the pads and the disc.
This action prevents the piston from holding the inner brake pad against the disc and also allows the piston to extend further out of the caliper chamber to compensate for brake pad wear.
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