What is the reason for the disc brake master cylinder not pumping oil?
2 Answers
Generally, it is caused by air in the brake master cylinder, brake fluid or oil pipe, blockage in the brake master cylinder or oil pipe, or loss of pressure due to wear of the brake master cylinder plunger. If oil still does not come out after cleaning, it is best to replace it. The following are related introductions: 1. Working principle: The working principle of the disc brake system is to install a disc that rotates synchronously with the wheel on the hub, and install a caliper on the fork and frame, then clamp the disc through the brake pads inside the caliper to achieve the braking effect. 2. Maintenance measures: Regularly check the brake disc and brake oil pipe, and repair in time if the brake is found to be ineffective.
I've been working with cars for decades, and there are quite a few common reasons why a disc brake master cylinder won't pump fluid. Insufficient brake fluid can directly cause this issue—first check if the reservoir level is low. Worn seals or a stuck piston inside the cylinder can also block the fluid passage—I've fixed many cars where this was the culprit. Air entering the system and forming bubbles prevents smooth fluid flow, requiring bleeding. Leaks or blockages in the lines, like cracked old rubber hoses, can let fluid escape. Also, ABS pump failure might be the troublemaker—if its electronic components malfunction, it affects hydraulic pressure output. Generally, inspect from simple to complex: first check fluid level, then look for leaks, and finally consider disassembling the cylinder for cleaning or replacing seals. I recommend finding a reliable repair shop to fix it promptly—delaying increases the risk of brake failure. Don't forget to regularly replace brake fluid during maintenance to prevent aging.
