brake fluid dot 3/4

[Church6360]

i just had an idiot moment, not only did i buy dot 3 instead of dot 4 but i even filled and bled my brake system before i realized i was an idiot.

questions

1 is this harmful to my brake system?
2 what exactly if the difference between the two?
3 if not harmful what will it do?

the cap for each resivoir even says in big letters "use DOT4 only"
i suck, help please.

[Briggs]

To my knowlege DOT4 has a higher max temp. Thats all I know.

[callmelenny]

My understanding is that 4 has higher boiling point (due to ester additives) and so mixing them brings the boiling point below 4 value.  Otherwise they are very similar glycol compounds. Dot 5 has silicone and the 3/4 and 5 should not be mixed.

I have always heard that mixing 3 & 4 is not a problem as long as you take the boiling pt change into account. Unless you are riding in track-like conditions I doubt you could tell the difference.

The stuff is so cheap, just change it again when you get a chance.

[coll0412]

Yeah, I will have to double check on Saterday when I goto to work, but I think you are not supposed to mix them. Valvoline I know makes a synthetic brake fluid that can be mixed with DOT 3 and 4, but I think you are not supposed to mix.

hmm....time to do some research(and not homework again)

[coll0412]

AND THE SURVEY SAYS.....

Prefectly fine to mix, just don't throw in any DOT 5

but you can put in DOT 5.1

so you will be fine, might be a good idea to swap it out anyway since DOT 3 has a lower boiling point than DOT 4, so less performance....

[Church6360]

yeah, i thoguht it was just a boiling point thing. my lines were completely empty, so it is just dot 3. next chance i get i'll switch over to dot 4. i'm a pretty tame rider anyway, so it should be fine. just curious if there was somthing seriously wrong with what i was doing. thanks to all for the info