You can change your choices at any time by visiting Cookie preferences, as described in the Cookie notice. With a higher boiling point than DOT 3 fluid, this fluid is ideally suited for higher performance vehicles where the braking system routinely reaches moderate brake temperatures. Glycol fluid is highly corrosive and contact with paintwork by fingers contaminated with brake fluids can cause severe paint damage.

It is compatible with most modern braking system components including seals, calipers and brake hoses.Glycol based fluids are hygroscopic which means they absorb water/moisture from the environment at normal atmospheric pressures at a rate of 2-3% per year. Brake fluid manufacturers can and often do improve on these figures and it is possible to find DOT 4 brake fluid with a higher boiling point than some DOT 5. Our BF307+ high performance Super DOT 4 brake fluid has been specially formulated to provide outstanding performance for braking systems routinely operated at extreme temperatures making this fluid ideal for fast street use, track days and racing. As water enters the system, instead of pooling in low spots (such as the caliper), due to its weight in comparison with brake fluid, it is dispersed throughout the whole of the brake fluid.

DOT 5 Silicone Brake Fluid repels moisture so, unlike standard polyglycol brake fluid, it never needs changing. high performance brake fluid is recommended for use in the hydraulic brake and clutch systems of all cars, commercial vehicles and motorcycles for which a non-petroleum based fluid is specified. Let's remember that the Department of Transportation specify the minimum wet boiling point of DOT brake fluids after absorbing only 3. are fully compatible with each other and can be readily mixed or swapped without adversely affecting the brake's performance or its characteristics.

It was originally introduced to give a higher boiling temperature over glycol-based DOT 4 brake fluid. DOT 4 brake fluid is a high quality brake fluid recommended for use in the hydraulic brake and clutch systems of all cars, commercial vehicles and motorcycles for which a glycol based DOT 3 or DOT 4 fluid is specified. Recommended for use in the hydraulic brake and clutch systems of all cars, commercial vehicles and motorcycles for which non-petroleum based fluid is specified. Eurol Brake Fluid DOT 5 Silicone can safely be used in hydraulic brake and clutch systems of cars, (racing) motorcycles, Harley Davidson bikes, go-karts, old-timers and in industrial applications. Here you can see that silicone based DOT 5 is the odd one out and is not compatible with any other DOT brake fluid.

As Tiger said, DOT-4 fluid does need frequent changes to make sure moisture buildup in the fluid does not cause problems.

is fundamentally different than the rest of the DOT fluid range in that it is silicone based brake fluid. The brake fluid also has to resist, as far as possible, the high temperatures created by the braking forces. Since every Shimano brake uses Shimano brake fluid, we have complete control over the process and can assure consistent performance. Automec’s performance silicone DOT 5 brake fluid repels moisture so, unlike standard polyglycol brake fluid, it never needs changing. These are the minimum temperatures that the brake fluid must perform at before the brake fluid starts to boil, which can lead to complete brake failure.

has a significantly higher boiling point than standard DOT 3 and DOT 4 fluids and is therefore well suited to modern high performance vehicles and/or vehicles fitted with ESP/ASR systems. Clearly the manufacturers have a vested interest in recommending and insisting that consumers use only there oil and to be fair why wouldn't they? DOT-5 does have the reputation of damaging the hydraulic brake pressure switches used on early cars. Are Shimano simply trying to put the frighteners on people so they use nothing but Shimano's own branded Mineral Oil?

Also the fact that it is regulated by the federal government means that the brake manufacturers can concentrate on building brakes instead of formulating brake fluid, and be safe in the knowledge that the DOT fluid they're designed to be used with is of consistent high quality regardless of who should manufacture it.