Why does the brake require deep pressing to respond?
2 Answers
Brake requiring deep pressing to respond indicates that the braking has become soft. There are roughly three reasons for the softening of brakes: first, air has infiltrated the brake lines; second, the gap between the brake disc and the brake pad is improper; third, the master cylinder is abnormal or damaged. Other factors include insufficient brake fluid or contamination with water, leakage from the wheel cylinder, etc. Brake abnormalities significantly increase the risk of accidents and must be inspected and repaired promptly. Air infiltration in brake lines: When there is air in the brake pump and lines, pressing the brake first compresses the air. Since the compression ratio of brake fluid is less than that of air, the brake will feel soft, and the braking effect will be greatly reduced. In this case, simply bleeding the air from the lines is sufficient. Gap between brake disc and brake pad: When the gap between the brake disc and brake pad does not meet the vehicle's standards, the braking effect can also deteriorate. This issue may be caused by grinding of the brake disc or aging of the brake pad. If the gap is too large, it can even lead to severe situations such as the brake pad falling off. The solution is to inspect or replace the brake disc and brake pad. Master cylinder failure: The brake master cylinder consists of the pump body, piston, and brake fluid reservoir. Under normal braking conditions, the master cylinder sends brake fluid to the wheel cylinders, causing the brake pads to frictionally reduce the vehicle's speed. When the brake is released, the brake fluid flows back under the pressure of the master cylinder piston. If the master cylinder fails, it may prevent the brake fluid from being accurately distributed. The solution is to replace the brake master cylinder.
I've been driving for over twenty years, and the issue of having to press the brake pedal deeply to get a response is a common one. Usually, insufficient brake fluid or air entering the brake lines are the main causes, making the hydraulic system less firm. Once, while repairing a car, I found that the owner had neglected to top up the fluid, which nearly caused an accident due to ineffective braking. Excessive wear on the brake discs, where the pads don't clamp tightly, can also lead to this issue. I recommend immediately checking the fluid level and its color; if it's black or has bubbles, replace and replenish the fluid right away. Aging and cracked hoses or master cylinder failures are also potential hazards that shouldn't be ignored. Safety comes first—perform a self-check every six months, as repair costs are worth more than an accident. Avoid slamming on the brakes while driving, and maintain your car regularly to extend the lifespan of its components.
