Bosch ESI6 Extended Service Brake Fluid

Brake fluid is unique among the different lubricants/hydraulic fluids in use in automobiles for one very particular reason: it's not oil based. DOT-3, -4, and -5.1 brake fluids are glycol based, and their hygroscopic nature to absorb water prevents any water that sneaks in via damaged seals from pooling in the low points of the system, where it could rust, freeze, or boil off.

This hygroscopic sword cuts two ways, however: brake fluid absorbs moisture from the surrounding air over time, and as the water content of brake fluid increases, its corrosion protection and boiling point/temperature resistance both fall off. Automakers thus suggest regularly flushing your brake system to maintain brake performance and prevent internal corrosion, and we've found flushing every two years or so is one of the most effective things you can do to extend the life of your brake system.

Modern brake systems, such as those featuring ABS and ESP®, are designed for improved performance to safely stop vehicles. With improved performance comes a higher load on the braking systems. These systems require a brake fluid with a high wet boiling point, low viscosity, and high lubricity.

As a vehicle system developer and the first to market ABS and inventor of ESP®, Bosch understands the need for a high quality brake fluid, and their ESI6 fluid is one of the best we've encountered. It exceeds all current DOT standard requirements (FMVSS 116), making it the best value on the shelf:

• First to simultaneously combine both low viscosity and high wet boiling point at its operation
• Longer lasting: 100% longer than DOT 3, 50% longer than DOT 4, and 10% longer than DOT 5.1 (with 30% lower viscosity)
• ESI coverage includes the majority of all brake systems launched since 1990; Use with DOT 3, DOT 4, or DOT 5.1; Coverage excludes DOT 5 silicone based brake fluid which is limited to military and racing applications
• Excellent lubricity properties to prevent wear of components in the brake system and reduce noise
• One size fits all: As Bosch ESI6 can be used to substitute almost all previously used brake fluids, e.g. DOT 3,
  DOT 4, DOT 5.1 (except LHM), it fits practically any brake system launched since 1990.
• Bosch ESI6 helps reduce the stock of brake fluids thus saving storage space.
• Featuring replacement intervals of 3 years, Bosch ESI6 high-grade brake fluids last much longer than
  standard DOT 3 brake fluids (to be replaced every year and a half).
• Bosch ESI6 reduces corrosion within the brake system and its high lubricity prevents noises and wear inside
  ABS and ESP® systems.