What are the reasons for soft brakes?
3 Answers
As a crucial component for safe driving, brakes should be given special attention by every driver. Before each drive, it's advisable to test the working condition of the brake pedal. When the engine is not started, the brake pedal will feel very firm; after normal engine startup, the brake pedal will slightly sink. The reasons for soft brakes include the following: 1. Mixed brake fluid: Using different brands of brake fluid together can reduce braking performance. 2. Air in the brake fluid: The presence of unexpelled air in the brake fluid. 3. Oil leakage or poor sealing: Oil leakage in the master cylinder or wheel cylinders, or poor sealing. 4. Damaged outer packaging: Damage to the external casing of the brake lines.
A soft brake pedal, where it feels empty and lacks strength when pressed, right? Common causes include air getting into the brake fluid. Air in the lines is like inflating a balloon—you press, and it loses force. If the brake fluid deteriorates or absorbs moisture, it can create bubbles at high temperatures, making the pedal soft. Another possibility is a leaking brake caliper, where insufficient oil pressure leads to weak braking. If you've recently replaced brake pads or discs and feel the pedal is softer, it might be due to air trapped in the lines not being fully bled. Additionally, worn master cylinder seals or swollen, aged brake hoses can cause this. Rubber hoses can deform under high pressure over time, leading to pressure loss. This issue should be taken seriously—check the fluid condition and line seals immediately.
Speaking of soft brakes, my old car had this issue before. The pedal travel became longer with less stopping power, which could be due to several reasons: the brake fluid was old and deteriorated, absorbing moisture and lowering its boiling point, causing vapor lock; leaks at pipe connections or wheel cylinders leading to insufficient hydraulic pressure; or air not being fully bled after replacing brake pads. In my case, the inspection revealed a slight leak at the left rear wheel cylinder. Replacing the cylinder and the brake line fixed the problem. I recommend first checking if the brake fluid reservoir level is low, then looking for any signs of fluid leakage. If you're not comfortable doing it yourself, it's best to visit a shop for professional equipment to test the hydraulic pressure—safety first.
