Attention! Regularly check the brake fluid level in the master cylinder reservoir. The brake fluid level should be near the "MAX" mark on the reservoir body.
A drop in the fluid level indicates either a leak in the brake fluid system or excessive wear of the brake pads. If the low brake fluid light comes on in the instrument cluster, do not rush to top it up immediately, first check the thickness of the brake pad linings: maybe it is time to replace the pads?
Car manufacturers recommend after 90,000 km or 4 years (whichever comes first) change all brake fluid in the system.
[Original version on our portal: Renaultbook.ru]
Some drivers ignore this advice because the fluid in the reservoir seems clean enough, and this is completely in vain. The fact is that brake fluid is very hygroscopic: it absorbs moisture from the air, which over time not only destroys the surfaces of brake cylinders, pipes and, as a result, leads to premature failure of brake system components, but also significantly reduces the boiling point of the brake fluid. The normal boiling point of DOT-4 brake fluids is 210–260°C. With frequent intensive braking, disc brakes heat up very much and with a high water content, the brake fluid can boil, which, as a rule, leads to brake failure.
Note: In order to avoid unexpected expenses in the future for repairs not only of the brake system, but of the entire car, it is better to replace the fluid in the brake system in a timely manner. We recommend replacing the brake fluid after 2 years.
If you experience problems with your brakes, bleed the brake system (see "Bleeding the brake system"). If this does not produce the desired result, the entire brake system must be thoroughly checked as described below (see "Checking the brake system").