DOT 3
DOT 3 is one of several designations of automotive brake fluid, denoting a particular mixture of chemicals imparting specified ranges of boiling point.
In the United States, all brake fluids must meet Standard No. 116; Motor vehicle brake fluids[1]. Under this standard there are three Department of Transportation (DOT) minimal specifications for brake fluid. They are DOT 3, DOT 4, and DOT 5.1.
DOT 3, like DOT 4 and DOT 5.1, is a polyethylene glycol-based fluid (contrasted with DOT 5, which is silicone-based). Fluids such as DOT 3 are hygroscopic and will absorb water from the atmosphere. This degrades the fluid's performance, and if allowed to accumulate over a period of time, can drastically reduce its boiling point. In a passenger car this is not much of an issue[citation needed], but can be of serious concern in racecars or motorcycles[citation needed].
DOT3 has been all but replaced with the superior DOT4 as there is little cost difference between the two.
[edit] Boiling points
Minimal boiling points for these specifications are as follows (wet boiling point defined as 3.7% water by volume):
| Dry boiling point | Wet boiling point | |
|---|---|---|
| DOT 3 | 205 °C (401 °F) | 140 °C (284 °F) |
| DOT 4 | 230 °C (446 °F) | 155 °C (311 °F) |
| DOT 5 | 260 °C (500 °F) | 180 °C (356 °F) |
| DOT 5.1 | 270 °C (518 °F) | 190 °C (374 °F) |
| DOT 2 | Brake fluids | DOT 4 | ||
|---|---|---|---|---|
[edit] References
- ^ Code of Federal Regulations, Title 49 - Transportation, Chapter V - Part 571 - Federal Motor Vehicle Safety Standards (49CFR571), Subpart B, Sec. 571.116 Standard No. 116; Motor vehicle brake fluids
- ^ http://www.afcoracing.com/tech_pages/fluid.shtml
.JPG){kind=small} |
This article about an automotive technology is a stub. You can help Wikipedia by expanding it. |
