#Dot 3 brake fluid ingredients skin#

Wherever possible, use what the manufacturer recommends, and don’t be tempted to use DOT 4 because you think it might improve performance.

Most modern DOT 3 brake fluids use synthetic lubricants rather than traditional mineral oil, but there are exceptions (some Rolls-Royce models, for example). The good news is it’s pretty hard to go wrong as long as you follow a few precautions. You want to buy DOT 3 brake fluid because that’s what the manufacturer says to put in your car or truck, but which one? To be fair, there are a lot of similarities, and it isn’t easy to choose between them. However, at many times the price of DOT 3, it isn’t popular, and in most cases, it doesn’t offer sufficient benefits to be worth the extra money. It’s not silicon-based, but it performs like DOT 5. The fact that it doesn’t absorb water means it won’t corrode braking systems if the vehicle sits unused for long periods.ĭOT 5.1 is chemically similar to DOT 4, and it can be mixed with it. Most vehicle manufacturers don’t recommend it, so it’s largely used in military vehicles. However, it does foam and can create air bubbles, which reduce effectiveness. If you’re regularly making long trips with lots of braking, or you like to take your classic car to track days, these are a good idea.)ĭOT 5 is silicone-based, so it doesn’t absorb water and can take higher temperatures as a result. (Note that some manufacturers’ DOT 3 specifications are higher. Some modern antilock braking (ABS) systems get very hot, so DOT 3 isn’t always recommended. (DOT 5.1 is the same.)ĭOT 3 remains the great all-rounder, but other formulations can take higher temperatures.

DOT 5 has a boiling point of 500☏ and a degraded boiling point of 356☏.

DOT 4 has a boiling point of 446☏ and a degraded boiling point of 310☏.

DOT 3 has a boiling point of 401☏ and a degraded boiling point of 284☏.The following numbers are minimums in order to comply with the stated category: In effect, it lowers the boiling point and thus reduces efficiency. The latter is when the brake fluid has absorbed 3.7% water, which takes about two years.

Mostly it’s about boiling point, and DOT standards quote two: dry boiling point (when new), and wet (degraded) boiling point. That makes DOT 3 the “baseline” product, but there are also DOT 4, DOT 5, and DOT 5.1. These components also make sure the brake fluid doesn’t freeze.ĭOT system: The DOT (US Department of Transportation) system of numbering brake fluid started with DOT 1 and DOT 2, but both are now obsolete. Petroleum-based oils are often used in machinery, but brake fluid uses a combination of solvents, lubricants (often synthetic), and corrosion inhibitors. Your brakes can hit over 350☏ with ordinary road use, and as much as 1,000☏ under heavy loads like racing. Water isn’t a good choice because it causes rust and boils too easily. Hydraulic systems, like the one used for the brakes in your vehicle, need fluid to generate pressure.

#Dot 3 brake fluid ingredients skin#

It doesn’t like skin much either, so wear mechanic’s gloves when you’re working with it. There is no better paint stripper than brake fluid, so be very careful not to spill any on your vehicle bodywork.