View source for DOT 3

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'''DOT 3''' is one of several designations of [[brake fluid]] denoting a particular mixture of chemicals imparting specified ranges of [[boiling point]].

All brake fluids must meet [http://www.nhtsa.dot.gov/cars/rules/import/FMVSS/ federal standard #116]. 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 performance of the fluid by drastically reducing its [[boiling point]].  In a passenger car this is not much of an issue, but can be of serious concerns in [[racecar]]s or [[motorcycle]]s.

Most cars produced in the US use DOT 3.

==Boiling Points==

MINIMAL boiling points for these specifications are as follows:
 

{| border=1 cellspacing=3 cellpadding=4 style="float:center; margin:0 0 .5em 1em; width:400px; background:#505050; border-collapse:collapse; border:1px solid #999; font-size:83%; line-height:1.5; " summary="Infobox Automobile"
|- style="text-align:center; background:#505050;"
|- tr BGCOLOR=darkred
|+'''Boiling Point Ranges'''
|-tr BGCOLOR="darkred"
!
! 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) || 191°C (375°F)
|}

[[Category:Automotive chemicals]]