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Old May 8th 19, 11:50 PM
Ventus_a Ventus_a is offline
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First recorded activity by AviationBanter: May 2010
Posts: 202
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Quote:
Originally Posted by Charlie M. (UH & 002 owner/pilot) View Post
Ummmm....yes, I am very happy with my post.
Pretty much ANY DOT fluid is cross compatible EXCEPT DOT 5.
DOT 5 "will work", but it is even MORE water hungry than others. I do not believe it is a seal issue, it is water absorption issue. Thus, race cars is fine, other uses, sucks.

Now, mineral based fluids vs. DOT fluids is a different matter. Thus my question.

Oh, and to accentuate this, if you have an old system that uses DOT 1, using DOT 1-4 AND 5.1 is fine.

Yes, I made a bold statement, I will do my best to provide GOOD relevant links to prove, not just me stating it. Say, within 24hrs?
Warning! General observations maybe present

Dot 5 is a silicone based fluid and is hydrophobic i.e doesn't absorb water. Dot 5.1 is glycol based and is hydroscopic i.e. does absorb water.

It's a PITA having the numbering system this way but it means that it's quick and easy (really?) to distinguish between the 2 types of brake fluid that meet the performance standard for Dot 5. Mix them at your peril

https://www.lubricants.total.com/brake-fluid-types

:-) Colin

Last edited by Ventus_a : May 8th 19 at 11:55 PM.