The braking system requires preventive maintenance for proper operation, and brake bleeding is one such activity that should be done once changes in brake pedal feel are observed. The kind of brake fluid used will contribute greatly to overall braking efficiency, as a high quality brake fluid will prevent boil over under extreme heat. When brake fluid boils, it produces moisture and air that will reduce the efficiency of the braking system.
Moisture and air inside the braking system will give your brake pedal a “mushy” or soft pedal feel. A situation such as this will require more brake pedal effort on your part to bring the car to a halt. Brake fluid is responsible for transferring the pressure of the brake pedal to the calipers on all four corners of the car. Once air or moisture is trapped in the system, the transfer of force will be affected, as air is easily compressed unlike liquid or fluids.
It would be a good idea to bleed the brakes once service has been performed on the braking system, such as changing the brake pads and fluid lines in the system. This will ensure that contaminated fluid is flushed out of the system to maintain peak braking performance.
When a change in brake pedal feel is felt, the usual remedy would be to have the system adjusted and bleed the braking system to restore normal pedal feel. As mentioned above, a soft or mushy pedal effort is the result of excess air trapped inside the system. Once an incident is felt on the brake pedal on your car, have a qualified mechanic bleed the brakes and replenish the reservoir with fresh and high quality brake fluid.