Corvus wrote:Merecat wrote:I don't think any fluid returns. You release the pressure and the pads release the grip on the disk. No pressure no braking effect although the pads will probably be in contact with the disk to some small degree........
What would happen, even in the short term, if the hole was blocked? If no flow into or out of the reservoir occurs, then we don't need the hole.
The hole is blocked when the brake is activated. The piston closes the vent hole to the res when the master cylinder is operated. The resavour is just that, to replenish the fluid that is required for the system as the pads wear. There is no flow as such. Pressure is transmitted equally to all parts of the system. This pressure acts on the caliper piston and clamps the disc. The fluid will move to fill the void. Moves as opposed to flow because the fluid is incompressible and acts almost like a solid.
When the lever is released it relieves the system pressure, venting to the resavour which is at atmospheric..
If the hole was blocked, the brake would still work, but more likely than not release the pads from the disk more slowly