Posted by Traveler on April 07, 04 at 21:30:03:
In Reply to: Re: Brake Fluid posted by Traveler on April 07, 04 at 20:10:30:
"...dry boiling point is applicable to fresh fluid and the wet boiling point to fluid has been exposed to moisture and has had the opportunity to adsorb water. It is the wet boiling point that is important to street vehicles because a brake system is not a tightly-closed system. The higher the wet boiling point the more desirable, and this is why I steer truck owners to the ATE and better (Motul and Castrol SRF).
FYI: here's the typical dry/wet boiling points of standard fluids:
DOT 3: 400/275
DOT 4: 440/310
ATE (Type 200/SuperBlue): 535/390
Motul 600: 580/420
Castrol SRF: 590/515"
"You have to be careful with 5.1. It has a different viscosity range than
DOT 3 or 4 that is more similar to DOT 5's (this is why the hybrid 5.1).
GM's modern ABS (95+ in trucks) CAN handle 5.1, but many other vehicles
(like Toyota, KIA, etc.) cannot. I just wanted to post this so people
realize there is more than just chemical compatibility at issue. DOT
ratings aren't just boiling points! They are also based on viscosities and
a few other parameter's I won't bore you with. FYI - if you got a real
touchy GM ABS, a DOT 5.1 or so-called SuperDOT 4 will help with that!"
(courtesy NJCKZ71)