You may have laughed at movie scenes where the brakes fail on a car going downhill, and the driver keeps praying out loud while pumping them frantically. This is, ideally, not something you want to happen to you in real life. Ideally, your brake pedals always feel firm when you push down on it, with this firmness increasing the harder you push. The upper limit on this firmness is when you simply mash down, such as when trying to keep from rear-ending someone.
With the engine off, power brakes generally feel very hard, but this changes after you start the engine. Your main problem is if the pedal goes all the way to the floor. This may point to a brake system breach that is letting out brake fluid, or air trapped in the brake lines. If you get a spongy feel when pressing the pedal, or if it goes immediately to the floor, you may want to check the brake fluid. The system operates on hydraulic pressure, which means if there is a leak somewhere, the pedal would give too easily.
- If you feel sponginess, there may be air trapped inside the braking system, meaning the brake lines need to be bled. This could happen even right after you have replaced the pads, lines, and fluid; air could get trapped inside the closed system and interfere with proper hydraulic functioning.
- If you have a soft pedal, it could be because the master cylinder has malfunctioned. In such cases, you should drive the vehicle to a repair shop right away, and find out if a replacement is due.
Difference in Brake Pad Material
If you switched brake materials and now have one which is softer (carbon-Kevlar to semi-metallic, for instance), the feel it gives would be a lot different. Generally, softer pads give more easily, although from the safety perspective, it is the consistency that largely matters.
Different Kinds of Brake Pedal Feel
The following are the most common ways brake pedals feel when pressed down on, and what each means.
- Going immediately to the floor: There is no pressure inside the master cylinder, or the system has a leak somewhere.
- Staying soft and going further than usual: There is brake fluid leaking somewhere.
- Feeling gritty: The pads are worn down, and the metal is grinding on the rotors.
- Going extremely hard, and essentially not working: The brake booster is faulty.