What is the reason for having to press the brake pedal very deeply before getting a response?
3 Answers
The reasons for having to press the brake pedal very deeply before getting a response are: 1. Air has entered the brake lines; 2. Improper gap distance between the brake disc and brake pad; 3. Faulty or damaged master cylinder; 4. Insufficient brake fluid or contamination with water; 5. Leaking wheel cylinder. Braking, also known as deceleration, refers to the action of stopping or reducing the speed of moving motor vehicles and other transportation machinery, which is divided into drum brakes and disc brakes. Precautions for using the brake pedal include: 1. When emergency braking, hold the steering wheel with both hands and do not operate it with one hand; 2. The free travel of the brake pedal directly affects braking time and stopping distance; 3. Braking actions should be swift, and when the vehicle skids, release the brake pedal, but the steering wheel must be turned quickly.
I once experienced this issue while driving a friend's car—the brake pedal felt spongy and I almost rear-ended someone. Later, a mechanic told me the most common causes are insufficient brake fluid or air bubbles in the system. The fluid reservoir is located in the engine bay, and if the level drops below the MIN line, it's time for a top-up. Worn brake pads are another major issue—when thickness falls below 3mm, the piston has to extend much further to make contact, requiring more pedal travel. Another possibility is a leaking or aging master cylinder, like the one I replaced last time for 500 bucks. Oh, and if the brake discs overheat and glow red during continuous downhill driving in summer, they can also go soft—best to pull over and let them cool for half an hour. This isn't something to take lightly—get the brake pressure tested at a shop right away. Don't wait for an accident to regret it.
I love tinkering with my car in my spare time, and I've given some thought to the issue of deep brake pedal travel. First, check the brake fluid level—pop the hood, locate the reservoir, and ensure the fluid sits between the MIN and MAX marks. If the fluid level is fine but the pedal feels spongy, it's likely air in the lines, requiring a two-person bleed job: one pumps the pedal while the other loosens the bleeder screws at each wheel. Also, brake pads thinner than 3mm must be replaced, as worn pads cause excessive caliper piston travel. A leaking vacuum booster will hiss and make the pedal stiffer under hard braking. Master cylinder internal leaks are trickiest to diagnose—look for fluid traces at the wheel cylinders. My old Jeep was fixed exactly this way once.
