whats everyone using for brake fluid ?

finally got some time to go for a ride today, got the bike out of the garage and noticed the front brake lever went all the way to the handgrip. also saw a small discoloration on the floor, but it didnt feel oily. brakes worked good the last time i rode it, (a month ago) . we were riding in some nasty mud and i probably got some up in or around the pistons and i will remove to see what happened. i have never had to add any brake fluid so im not sure what every one uses. the cover says to use dot4. i just wondered if it is the same as what you would get at the auto parts store ? thanks

Dot 4 and nothing more. You need a brand? Any is good as long as its dot 4

yep, DOT4 for me too. one brand is as good as another, here in oz there's heaps of brands but it's only made by two companies.

paul.

hey thanks, thats exactly what i needed to know, i will remove the caliper tonight after work and see where it leaked and why, hopefully just some old mud that i missed when cleaning up the last time. thanks again, mike

fluid leak

wow, that was an easy fix, the brake line bolt had come loose on the caliper. tightened up the bolt, i could swivel the brake line back and forth, filled up and bled then went out and rode. its all good i will have to remember to check those lines as part of my pre flight inspection. mike

Motul 5.1 It's compatible with 4.0 and holds up better.

umm........ no, it won't i'm afraid.
the higher the rating, 3, 4, 5.1 the higher the boiling point, which is great if it's a race bike that gets fluid replaced all the time, but on a bike that's serviced at it's regular intervals dot4 is the way to go.
the higher boiling point has a trade off, it's much more hygroscopic, that is to say it absorbs moisture from the atmosphere, which leads to problems like spongy brakes from the water boiling and turning to steam. localised corrosion is another drama, pockets of water will sit against bores of calipers and master cylinders which then cause leaks and contamination. If the brakes are used fully you can feel 5.1 pass it's best through the lever, especially when they're really pushed, if used normally you would probably not notice a drop in performance or feel, which is fine for the rider but not for the system, which will continue to be contaminated with moisture until changed.
note: dot 5.1 is a glycol compatible fluid and should not be confused with dot 5! dot 5 is silicone brake fluid and should not be mixed with glycol based fluid or used in a system that has had glycol based brake fluid in it unless correctly and completely flushed properly.


paul.

Motul RBF 600 Racing Brake Fluid DOT 4

Only stuff I've found that won't boil on me.

Thanks for the info. I guess it works for me(and many other racers in my area) because I flush it often. I would change out DOT4 just as often. Odd that a fluid with a higher boiling point would be more hygroscopic, seems contrary to logic.

Same stuff I've been using.......bit on the expensive side, but a lot better than hauling down a nasty downhill and having your brakes go away.

no worries

wow, thanks for all the info!!! i got a container of dot 4 and flushed out both front and rear systems, figured i wouldnt hurt . thanks again. mike

What I'd really like to use is Castrol SRF Racing Brake Fluid, but it's about $80 a liter.

Another good one is ATE super blue. It's cheaper than Motul 600 and very close for dry boiling point and just down a bit for wet boiling. I've used many different types with heavy cars and lots of power at the roadrace track (where you can really boil fluid) and have found that ATE is just about as good as Motul 600 as long as you change it often.

The SRF is absurdly expensive. It is the best stuff around but seems like overkill in the dirt.