[vtrider]

can you put dot 5.1 fluid in hfx-9HD's?
it says 3&4 four only, but i assume thats because they're glycol based, and other dot fluids are silicon.
however, dot 5.1 is also glycol. Is there any reason why i couldnt use that in my hayes? it has a much higher boiling point (over 500 degrees F), and can absorb moisture our of the air the same as 3&4, made of the same substance, how could this hurt?

 

[Brian HCM#1]

I would stick to what Hayes recommends.

 

[vtrider]

yea i figured that, but i was just wondering if anyone knows if you can or cannot. It seems like it would be an improvement.

 

[rfemurfx]

you can use 5.1. the reason Hayes does not recommend it is because if you do not know what you are looking at you could easily grab the wrong bottle. there is also a DOT 5 which is, as you may alreay know a silicon based fluid and it is NOT compatible with any other fluid. as far as being an improvement i am not so sure. it is not very likely that you will ever need such a high boiling point, and since DOT fluids will not absorb more than 3 percent of moisture you are not really gaining any real advantege. aside from a mental stand point.

 

[vtrider]

yeah i didnt figure there would be much, however, i just had to purchase a brand new set of hayes mags because i boiled the dot 4 fluid, frying my caliper, and loosing me my brakes on a pretty knarly plattekill downhill. It seems as though this couldve been avoided by using dot 5.1, but i dont really want to mess with it. If it happens again however....