Mixing different brake fluids

Ben.Taylor

Hi everyone, does anyone know if you can mix DOT 3 and 4 fluids? I want to top up some new brakes, shop not sure which fluid is in - it's not 5.1 which I know is incompatible with the other 2 as they are Stroker Ryde and they use 3 OR 4.

ThreeFish

DOT 3, 4 and 5.1 are all glycol based fluid and can be mixed; however, your system fluid is only going to be as good as whichever fluid has the lowest boiling point. Bearing this in mind, it's worth flushing through whichever new fluid your choose to remove as much of the old stuff as possible.

For the record, DOT 5 fluid is silicone based and not compatible.

dave_hill

And don't mix mineral oil (as used by Magura and Shimano) with glycol based fluids either.

If they are Strokers, have you looked at the instructions to find out what fluid they need? Or checked on the Hayes website?

tombate911

yep they can be mixed as said before, there is a very good video on youtube that was created by hayes if you are a little unsure about bleeding your stroker rydes, they are very simple to do,

Ben.Taylor

Thanks for the advice everyone, will go for DOT 4 and flush out the old stuff as much as possible instead of topping up- hope it goes better than my last botched effort! Used the link from here to get to Hayes video guide, not being funny, but I (and my park tools repair book) thought that you tilt the bike so that the caliper is at the bottom of the frame angle, rather than tilting the frame forwards and raising the caliper end ?

tombate911

it can be done with the bike left in the position it is just release the caliper mounts so i can be moved around to get the air out and loosed the leaver so that it can also be rotated on the bars along with pulled to get the last of the air out as show in the video from hayes on youtube,