Comma BF51L Dot 5.1 Synthetic Brake Fluid, 1 Liter

Product Information

Do not mix brake fluid types.A DOT 5 is strictly not allowed to mix with any other fluids. While DOT 3 and DOT 4 are technically mixable, it is still NOT recommended since they can react badly and corrode the brake system. Modifier Coupler: Swelling on the exposed rubber components may be controlled using a Modifier Coupler. The boiling point lowers over time, as more moisture is let in and your brake performance suffers, leading to reduced stopping power and possible brake fade.

Even though the big feature of DOT5 brake fluid is its high boiling point, it's worth noting that there are other fluids that have higher boiling points that are glycol based. When we listed the boiling points for things like DOT3 brake fluid and DOT4 brake fluid, those were the minimum requirements. A brake fluid like Prospeed RS683, for instance, is a DOT4 brake fluid that has a dry boiling point of over 300 degrees Celsius, or 583 degrees Fahrenheit. This is generally reserved for high-performance vehicles that will run their brakes at extreme temperatures, things like racing cars. The advantages of mineral oil are that it tends to last longer and it’s not corrosive to your bike’s paintwork. That said, if any does manage to get onto a component or paintwork, you should still wipe it off with isopropyl alcohol and a rag.The Society of Automotive Engineers SAE has published standards J1703, J1704, and J1705, reflecting progressively higher performance for brake fluids. These have counterparts in the international standard, ISO 4925. DOT 5 is a silicone-based fluid and is separate from the series of DOT 2, 3, 4, 5.1. It is immiscible with water, and with other brake fluids, and must not be mixed with them. Systems can change fluid only after a complete system changeover, such as a total restoration. The primary function of the brake fluid is to control the movement of the braking system’s essential components. The brake fluid enables the pistons in the braking system to compress the rotors, allowing the vehicle to slow down.

Still, though, it has the same temperature characteristics as the DOT 5. This means that it has a dry boiling point of about 500 degrees Fahrenheit and a wet boiling point of 356 degrees Fahrenheit. Which is a good improvement over the old designs such as the DOT 3 and 4. But what about the DOT 5 brake fluid, what are its pros and cons? Well, that’s what we are going to cover next. Pros & Cons Of Dot 5 Brake FluidThis means you should avoid mixing mineral oils and you’ll normally need to buy it from a local bike shop or online bicycle retailer, unlike DOT, which is more readily available given it’s used in the automotive industry. Now let’s cover some of the pros and cons of the DOT 5. Knowing these things is really important to determine if you want this type of fluid on your car.

DOT 3 as we mentioned is a glycol-based type of fluid. It has a much lower heat resistance temperature and is old technology. In terms of performance under heavy use and abuse it is quite poor and you should definitely switch on a DOT 5.1 fluid if you want to get something better performing and something that will deliver a lot. And what is good when it comes to these two types of fluids is that they are really interchangeable. You can flush the old DOT 3 and replace it with 5.1. And what about the difference between DOT 3 and DOT 5 brake fluid? What is different between the two fluids and what are the pros and cons of each one? DOT2: DOT2 brake fluid has a dry boiling point of 190 degrees Celsius. The wet boiling point is 140 degrees Celsius. This is a mineral oil-based fluid and is rarely used in the automotive industry thanks to its relatively low boiling points. A good example of its use is in military vehicles which can be stored for long periods of time but need to be ready to be used at a moments notice. It is also favoured by some owners of classic cars for vehicles which may also rarely be used on the roads.

Here's where things get a bit hazy. Unlike DOT fluid which is pretty clear cut, mixing Mineral Oils is an altogether different story. The disadvantage of mineral oil is that it’s unregulated and as a result, not all mineral oils are created equal. The different numbers in brake fluid represents the different ways that these brake fluids handle temperatures. The rating refers to the fluid’s boiling points when they are either wet or dry. Brake fluid with a higher boiling point will typically last longer than one with a lower boiling point. As you can see all of the glycol- based DOT fluids (3, 4 & 5.1) are fully compatible with each other and can be readily mixed or swapped without adversely affecting the brake's performance or its characteristics. The main change will come in a decrease or increase in the boiling point of the brake fluid as a whole. The effects of this water content over time are better illustrated by the graph below. This graph is taken from Shell and gives an overview of the declining effect water content has on its range of DOT 3 and DOT 4 brake fluids.

Hold on a second, although we've just made water out to look like your new worst enemy, the hygroscopic nature of DOT brake fluid is actually an advantage in a major way. What are the issues with having brake fluid filled to above the 'max' point - will a car fail an MOT with the fluid overfilled?; DOT 3, DOT 4, DOT 5, and DOT 5.1 are brake fluids named according to their boiling points– with DOT 3 having the lowest boiling points and DOT 5.1 having the highest boiling points among these fluids. The minimum boiling point of DOT 5.1 fluid is 270 degrees celsius when dry and 190 degrees celsius when wet (ie. some water has ingressed into the system). How simple is removing some to reduce the level? Is it as simple as taking the cap off and using a syringe to take fluid out of the tank, then replacing the cap, or is it always necessary to bleed the brakes?

Properties

The main advantage of DOT fluid is it’s widely available and not only from bike shops or specialist online retailers, because it’s also used in the automotive industry. It’s also generally cheaper than mineral oil. The Federal Motor Vehicle Safety Standards (FMVSS) under FMVSS Standard No. 116 [5] defines grades DOT 3, DOT 4, DOT 5 and DOT 5.1, where DOT refers to the U.S. Department of Transportation. These are widely used in other countries. Their classifications broadly reflect the SAE's specifications, DOT 3 is equivalent to SAE J1703 and ISO class 3, DOT 4 to SAE J1704 and ISO class 4, etc. [6]