It's one of the most asked questions when it comes to hydraulic sim racing pedals. Which brake fluid is the best to use? We've been through the test of them all and we wanted to make you aware of why one of them is by far the best choice for your hydraulic pedals at home...
When we first began building hydraulic pedals we didn't think much of which brake fluid we should have used when we were bleeding them. We would use the fluid we had available. Sometimes it was DOT 3, sometimes it just happened to be DOT 4. There isn't a difference between these except for the fact that they have different boiling points.
Being these pedals are used for the sim, most likely in your house, temperature isn't going to be an issue. But, that's not really what's important.
You see, both DOT 3 and DOT 4 are glycol based blends and they're highly corrosive. If they were to spill on your simulator they can eat up the paint and make damage. They could even damage floors if they leak and the fluid isn't taken care of.
But DOT 5 is a little different. It's a silicone based fluid and isn't corrosive at all... Actually, it could sit on your floors for hours and won't end up damaging them like the other fluids would. This is a huge plus and big bonus when it comes to thinking about what kind of fluid to use.
DOT 5 is specifically made for older vehicles. Ones that don't have ABS systems installed. The reasons is because when DOT 5 is shaken it foams and loses it's hydraulic properties. On simulators, there are no ABS systems. Your human foot can't press the pedal fast enough to simulate that of an ABS system. That makes it a perfect choice.
An extremely easy way to know if DOT 5 is being uses is to look at the color of the fluid. It is the only purple brake fluid available on the market. Popping the cap on the master cylinder will easily show you the color of the fluid inside. Unfortunately, it is a little more expensive to use but the benefits of using it greatly outweigh the damage a spill could create without it.