Final answer:
Without gear hydraulics, brakes may still function, but inefficiently due to the compressibility of gas. Hydraulic systems, like brakes that apply Pascal's principle, need incompressible fluid to transmit pressure effectively, which is why air must be bled from the system.
Step-by-step explanation:
If you lose gear hydraulics, you technically could still have your brakes; however, they would not operate as efficiently due to the compressibility of the gas that might be used in place of the liquid hydraulic fluid. In hydraulic systems, specifically hydraulic brakes, Pascal's principle is utilized to effectively transmit pressure from the brake pedal to the wheel cylinders. Fluids are incompressible, which makes them ideal for this purpose because the pressure applied at one point is transmitted undiminished to other points within the fluid. However, if a gas were used, which is compressible, it would compress and warm when force is applied before transmitting the pressure to brake. This could result in inefficient braking. Therefore, it is critical that the air is bled out of the brake lines to ensure that the hydraulic fluid can operate effectively and the brakes can work properly.