# Freezing point of Dot 3/4?



## InspiringTech (Sep 9, 2002)

It's been hitting 30 below the last couple days where I live, and it started to get me wondering what the freezing point of brake fluid is. I know that typically the major issue, and of course an easy question to answer, is the boiling temperature of brake fluid, but there has got to be a freezing level, and I'm just hoping someone has an answer for me. TIA


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## InspiringTech (Sep 9, 2002)

*Re: Freezing point of Dot 3/4? (InspiringTech)*

Ok, to semi answer my own question, it has to be less then -40, because I found viscosity specs for dot3 and dot4 at -40. Still curious if anybody knows.


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## 03Jetta1.8T (Dec 21, 2002)

*Re: Freezing point of Dot 3/4? (InspiringTech)*

never really heard of the "specs" for freezing point. Although thats realitive since it would depend on the water content in the brake fluid. I know the US average for water content is nearly 1% per year and doesnt usually go much higher then 4% on very old fluid. Maybe thats why there are no specs documented since water content is a variable.


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## spitpilot (Feb 14, 2000)

*Re: Freezing point of Dot 3/4? (03Jetta1.8T)*

Gotta be way down there...if you keep flushing the fluid to eliminate moisture content..every other year! You know they sell cars in Alaska and I've never heard of any special brake fluid for low temps so I'd say its freezin point is -100 degress F or somethin like that because the Feds would require special fluids and an warning not to use std ones if temps below -XX degrees...if there was a safety issue! http://****************.com/smile/emthup.gif


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## InspiringTech (Sep 9, 2002)

*Re: Freezing point of Dot 3/4? (spitpilot)*

That is kind of where my thoughts were going as well. Thanks for the insight. Anybody care to gander at what they use on the big rigs in Antarctica? Can't think of what they are called, but the over sized semi's that are just snow drivers?


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## Mohudsolo (Feb 25, 2004)

*Re: Freezing point of Dot 3/4? (InspiringTech)*

All the big rigs I've ever seen use air brakes. I don't know what the big snow trucks run but the air brakes I've seen seem like they could freeze up easily so I suspect they are somewhat different.


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