I bought some Honda brake fluid at a dealership thats DOT 3. The capon the resevoir in myengine baysays to only use DOT 3 or DOT 4. On the bottle it says to not mix with a dif DOT, should I just hope that the current fluid in there is DOT 3 and pour some in lol? Whats the worst that can happen if it's different and does it really matter? I just wanted to top it off because it's a little low.

 

in my opionon i would use it. but thats me. like i said its hard to say whats in there allready. you could always flush your break fluid at a local break shop this way you know for sure whats in your car.

 

I would bleed all the brakes till the fluid you already have in there is down to the "min" level (but not below) on the master cylinder. Or you could just suction it out with a bulb. Then add new stuff(gently over a spoon so as not to mix them too much, like pouring a "black and tan"), bleed until you're satisfied the old stuff is out(refilling as you go of course). I've never done it(mixing DOTS), but it seems logical to me. Using a brake bleeder with a vacuum pump would be best, that way the piston-action of pumping the brakes won't cause it to mix.

 

flush it out with DOT 3. DOT 4's are like used for I dunno, european, or volkswagon cars. Worst that could happen...brake failure maybe? Not too bad eh?
The truth is I don't know, but because you don't know, don't mix

 

where did you hear that DOT 4's are used for european cars? Is that a guess or did you hear that from somebody? Then I could just add the DOT 3. Does anyone know if there car came with DOT4 here in the states?

 

you gotta use the DOT 3. DOT 4, I think Volkswagon had been using for AWHILE.
I heard it from my instructor in Auto Tech class...I don't quite remember if it's DOT 5, but DOT 5 is supposed to be a real bad brake fluid

 

the DOT rating is the thickness of the fluid....DOT 3 is thinner than DOT 4, so if you want a little better braking they recommed go to DOT 4 over DOT 3 (if thats what you have) but the reason you shoudlnt go over is because DOT 5 (if they make it, i think so, but its for BIG stuff) would be too thick and could harm the braking system or just cuase it to be less effective.

*EDIT* to answer your other question, i would just have it flushed at a good break shop and have the dot 4 put in...but thats just me.

 

well, I just wanted to top it off because it was a little low....But I guess to be safe I'll just sell this DOT 3 bottle on ebay and get it flushed and have them put DOT 4 in.