The brake warning light indicates that the oil level in the brake center cylinder is low and that the brake fluid in accordance with the DOT 3 or DOT 4 specifications must be added. Under normal conditions, the changeover time of the brake fluid does not depend on the mileage. However, 12 months or 20,000 km for DOT 3 and 18 months or 30,000 km for DOT 4 is acceptable. DOT 3 and DOT 4 are brake fluid characteristics with hygroscopic properties. DOT 3 and DOT 4 have different boiling points. DOT 3 boils at 140 ° C and DOT 4 at 155 ° C. For this reason, DOT 3 must not be used on vehicles that need to use DOT 4.
Vehicles often work hard in cold weather. The oil that is thickened in very cold weather cannot circulate easily in the engine at the first run and therefore there is some problem in the first run. Low viscosity (thin), partial synthetic or fully synthetic oils should be used, especially in cold weather conditions.
DOT 3 Brake Fluid: DOT 3 brake fluid is glycol-based. The dry boiling temperature of this fluid is 205 ° C. The boiling temperature of 3.5% water absorption brake fluid is reduced to 140 ° C.
DOT 4 Brake Fluid: DOT 4 brake fluid (DOT 4 brake fluid) is based on borate ester.
Hygroscopic: Glycol based hydraulic brake oils are hygroscopic and absorb moisture during use. Hydraulic braking lubricants should be replaced every two years.