So now I'm a bit worried, so I looked at the specs on one of the cans.
It says;
This DOT 4 motor vehicle brake fluid meets or exceeds FMVSS 571.116/DOT 4/DOT 3 (except the blue color), SAE J1703 and ISO 4925, class 4.
Can be mixed with brake fluids meeting the same specification, and with DOT 5.1 brake fluids.
Boiling point is 280C/536F.
Wet boiling point is 196C/386F.
Our trucks are DOT3? This stuff is DOT4, but works with DOT's 3,4, and 5.1? Time to start googling I guess.
---------- Post added at 09:49 AM ---------- Previous post was at 09:26 AM ----------
Ok, I googled wikipedia, and read about brake fluid here.
http://en.wikipedia.org/wiki/Brake_fluid
It turns out that there are three types of brake fluid. Mineral Oil, Glycol, or Silicon. DOT's 3,4, and 5.1 are glycol(The most common) and DOT 5 is silicon(US military). Wikipedia doesn't say, but I' don't think that mineral oil brake fluid has been used in generations.
The different DOT's refer to the boiling points. Because this ATE stuff is racing brake fluid it goes all the way to DOT 5.1. Good stuff, maybe overkill for our trucks though, but good peice of mind. DOT's 3,4,and 5.1 are compatible with our trucks and can be mixed with no issues. Changing over to DOT 5 silicon fluid should be done by a pro, and no mixing should be allowed.
Glycol brake fluid is designed to not eat rubber seals or gaskets. Mineral oil brake fluid will eat rubber seals and gaskets. Silicon stuff also does not eat anything rubber.
This ATE blue stuff is Glycol based, not mineral oil based. Ergo, it is safe, and I am no longer worried.
BTW, both the ATE can and wikipedia suggests that brake fluid be flushed out every 1-3 years or so. Our trucks by OBS definition are at least 11 years old or older. Odds are it's the original brake fluid still in there. I think mine was. So any kind of brake fluid flush would be a good thing.