Honestly, how long have you left yours in?

[MikeT]

How long has your brake fluid been in your bike? How long should it stay in? My brakes still work well, but not as good as a 2003 KX125 which has much better brakes than I have. Is that because I need to change my fluid? Will changing my fluid make any difference at all??

As far as changing the fluid, should I just bleed the brakes and just keep pouring fluid in the top until I'm sure I've poured in more than the system can hold? Or is the best way to just drain everything and start pumping it up.

Tell me your views on this.

 

[bscottr]

Mike,
Get a Mity Vac to COMPLETELY bleed your systems. Change the fluid and bleed all at once. When the fluid starts appearing fresh and clean in the Mity Vac reservoir you're done. Just wait to see how nasty the old fluid is coming out of the rear brake. :scream:

Good Luck.

 

[biglou]

I'm almost embarrassed to say, I've not kept a bike long enough to change the brake fluid-yet. I'm settling into a nice groove with the 426 and it's coming up on a year old now. The kTm has been in the stable for 1.5 years, but is up for sale.

 

[jmics19067]

I never "change " my brake fluid. I do bleed them on occasion so I guess it cycles from old fluid to not so old fluid once in a while

 

[Lorin]

Front and back every few months (with a Mitty Vac). Once you get used to them being a certain way, you can feel the difference. It is fairly inexpensive and easy to do once you get a mitty vac.

 

[Danman]

I second the use of the Mitty Vac. I don't have the good metal one, but after useing the plastic version if it ever wears out I will be investing in the metal version that they make. I don't change it as much as lorin, but I check it every couple of months and change it maybe twice a year, more if it looks dirty. It should be the same color as it came out of the bottle.

 

[DANIEL JOSEPH]

Same here, I Use the Mitty Vac and suck out both brakes and the clutch at least a couple of times a year maybe more.

 

[MikeT]

Is it called a Mighty Vac or Mitty vac? How much is it? This is just a tool to make the job easier right? I wouldn't necessarily need it correct?

 

[DANIEL JOSEPH]

I changed my spelling It's probably is the Mitty Vac. It a small hand pump with a container to catch the Brake fluid. I got mine at Sears but don't remember the price.

 

[bscottr]

It's Mityvac and it's about $30 +/- for the base model. Does the job just fine. Click here for the website.

Nope...you won't need it, BUT you'll wish you had it.

 

[Rooster]

So, do you just slowly add to the reservoir as you pump the old out the bleeder into the MityVac container? Looks like a real hassle free way of doing your brake fluid.

 

[bscottr]

RoosteR13,
That's it. Reduces the pain immensely. :thumb:

 

[jmics19067]

yes if you do change the fluid dont ever let the master cylinder go down too low and you wont have to worry about bleeding the air out afterwards.

I am going to try it and see if I can feel the difference but 1/2 of the time I can't feel the dfference between the right and wrong side of a piece of sandpaper.

Not to sound too stupid but what changes? is it microscopic air dissolved in the water that gets absorbed by the brake fluid , or is it just not as smooth feeling from particulates floating in the dirty fluid?

 

[MikeT]

Good question.

 

[KSHAFFER]

my vote isn't on there. i change it before everyrace weekend. like said before, after you know how good brakes feel, you know when they get weak. when brakes get hot they boil and that makes air in the line. air makes it mushy feeling and somehow it gets dirty, even tho it's in a sealed system.

 

[MikeT]

shaffer, do you use this tool to change your fluid or do you do it without one?

 

[KSHAFFER]

no tool at all. i just have hose that fits on the bleeder and it's in a big knot so no air goes back into the caliper. i just open the bleeder and work the brakes till i see new, fresh fluid in the clear hose. then i close the vavle and pump them a couple times and bleed like normal a few times.

 

[MikeT]

Can you explain the big knot thing? So are you pouring new fluid in in the top while you're working the brakes??

 

[KSHAFFER]

just loop it like your tieing a knot in it, not tight that it shuts off the flow. it's only there so once the fluid gets so far in it that air doesn't go into the caliper. yes i'm adding fluid as it needs it. just pump it like 5 times add some and contiue like that.

 

[CRF150RaCeR]

how often do you have to change it, and how do u find out when u have to ?

 

[KSHAFFER]

i change mine when they get mushy or when i have to pull the lever to the bar to stop. even if you just bleed it once or twice. every so ofter they stay fresh. i just like the feeling of right now brakes.

 

[Luft]

I change mine as soon as soon as I detect a problem, i.e. air in the line. I flush the system 1 time with the fluid, then fill. I use a clear line with the loop and a mayo jar. The loop goes in the fluid in the jar. Put some fluid in the bottom of the mayo jar and then open the line. Don't let the resevoir completely empty. Pump the lever three or four times and hold the lever while opening the bleed, let a little fluid shoot out and then close the bleed. Then release the lever to pump agian. I've had good results with stainless steel lines and Galfer pads. The pads made the biggest difference.

 

[luvtolean]

Yes, brake fluid absorbs water. When you apply the brake the fluid heats up, and because water has a very low boil point, it can create steam pockets. This is part of what makes brakes with old fluid feel mushy. Once you have opened a container of brake fluid, it begins to degrade. This is why fluids have a wet and dry boiling point. Dry is pure fluid that hasn't been ruined by air, wet has absorbed water and become "wet". The best fluids handle the absorbtion of water well, and continue to have high boiling points when "wet" because they are better able to hold the water in solution. (I'm sure a chemist will come in here and correct me)

Heat also brakes down fluid. In my roadrace bike, I can feel the brake fluid degrade in a weekend of racing from the extraordinary heat the front brakes generate when braking at 160MPH. Dunno the chemistry behind it though...

I change mine frequently. Not really a fan of the mighty vac, although I own the high zoot metal version.

 

[MXP1MP]

It gets changed soon as the lever gets mushy or about every 6 months. I run motul and that stuff has like the highest wet boiling point I've ever seen so I know it last a good while. I think it will be more important to keep up on it now with the new style rear master cylinder/reservers.

 

[Rcannon]

What does 'change it" mean???? Why do we never bother to change it in our automobiles? can you imagine NOT being able to stop a car??????