Is it really ok to put dot 4 brake fluid into dot 3?

[BarraSSRX]

Hiy
Just wondering if anybody knows for sure! if it is ok to put dot 4 synthetic brake fluid into the dot 3 specified brake system on 2nd gen surf 2.4 ssrx jap import ??

I've heard conflicting answers about mixing dot 4 with dot 3, and especially wondering since the bottle of dot 4 that I have here says it's synthetic, some have argued that dot 5 cannot be used with dot 3 because! it's synthetic, well this dot 4 is fully synthetic too.

I need to top up the surf as it's on the minimum line, but wonder if I should wait and get some dot 3 ?

Any advice appreciated, thanks

[si tate]

It should say on the bottle " can be mixed with dot3" if so then it's fine.

[BUSHWHACKER]

Generally you can mix DOT 3 & 4.
You cannot mix DOT3 with synthetic fluid. Are you sure your DOT 4 is synthetic? it's not usually.

[Albannach]

DOT 3, DOT 4 and DOT 5.1 are all Polyethylene Glycol based, so can be mixed. DOT 5 is Silicone based so must be used on its own in a clean system.

[BarraSSRX]

Generally you can mix DOT 3 & 4.
You cannot mix DOT3 with synthetic fluid. Are you sure your DOT 4 is synthetic? it's not usually.

Yes it says synthetic and dot4 on the label

Thanks for all the advice and info everyone, much appreciated!