Caution: Brake fluid may cause damage to your eyes or painted surfaces if it comes into contact with them. Do not use brake fluid that has been open for a long time or that is more than one year old. Brake fluid tends to absorb moisture from the air, which can degrade its properties and lead to a dangerous loss of braking efficiency.
25. The brake fluid reservoir is located in the rear left part of the engine compartment (5 in the illustration of Section 1). Transparent walls of the reservoir allow the brake fluid level to be observed from the outside. To warn of a low brake fluid level, there is a corresponding indicator lamp in the instrument cluster (see Section 13 of the Chapter "Controls and Operating Techniques"). However, it is recommended to check the fluid level regularly.
26. The brake fluid level with the lid closed should be between the "MIN" and "MAX" marks on the front wall of the reservoir. Make sure that the level does not fall below the "MIN" mark.
27. If the level is low, first wipe the top of the reservoir and the cap with a clean rag to prevent dirt from getting into the brake system after removing the cap. Add fluid to the correct level, but do not overfill.
Note: Do not fill the brake fluid to the "MAX" mark if the brake pads are not new, otherwise the fluid will leak out of the reservoir after replacing the pads.
28. While the reservoir cap is removed, check the condition of the brake fluid and reservoir. If there are any rust particles, dirt or water droplets, the fluid should be replaced. After bringing the brake fluid level to the desired value, make sure that the cap is installed level to prevent fluid leakage and dirt from entering.
29. The brake fluid level will drop slightly as the brake pads wear. There is no need to top it up as long as the level remains near the "MIN" mark - it will rise after the pads are replaced. A very low level may indicate worn brake pads - check them (see Section 8).
30. If the brake fluid level drops constantly, immediately check the entire brake system for leaks. Inspect the brake lines, hoses and fittings along with the calipers, wheel cylinders and master cylinder (see Section 8). Brake fluid on models with manual transmission is also used in the clutch drive, so its lines and slave cylinder should be checked for damage and loose connections.
31. If, when checking the brake fluid level, the reservoir is empty or nearly empty, the brake system must be checked for leaks and bled (see Sections 8-9).
[Text taken from this website www.skodabook.ru]