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Discussion Starter #1
Well the manual says 15000k miles is time to replace the brake fluid. Me, I am not 100% certain I really need to do this. Maybe I do! I mean I have owned cars and put tens of thousands of miles on them without doing this. I realize a bike is not a car but I kind of think brake fluid is...., well I wonder how others feel about this. I mean, after reading that magnificent sticky about stators, this is the place for answers.
 

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I changed mine around 12k miles because it was two years old. Even though the bike had been parked for almost half of that time, the fluid was pretty gross looking.

I really can't tell a difference in how the brakes feel now, but I feel better trying to follow the recommendations.
 

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I have 15k and changed back brakes. The fluid actually did not look that bad. After changing pads and fluid, brakes seem to engage better. The brake pads actually looked very good but changed them anyway.
 

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After one year and about 6000 miles both of mine looked dark. Changed both front and rear. Not really sure about the difference in feel. Did it at the start of the season. Have to store my bike in the shed for the winter. That could be the reason.
 

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Well, just because you've gone a long time on your car, doesn't necessarily mean you should have. Also, your bikes brake system gets a lot hotter than your car, and has a lot less fluid.

The reasons you need to change your brake fluid are;

1) Brake fluid sucks up moisture from the air like no tomorrow. Over time, that moisture buildup reduces the fluids ability to handle heat, leading to potential brake failure.

2) Because of the aforementioned moisture, bad brake fluid can contribute to corrosion and rapid wear of components in your brake system. (i.e., caliper rebuilds are in your future if you neglect the fluid!)

3) Again, because of the moisture (notice a trend here?) old fluid leads to a spongy, less responsive brake feel.

If it's been 15k, I bet there will be a noticeable difference in braking performance after it's changed. Also, the sight glass on your master cylinder's real purpose is to let you know if the fluid is low. NOT to let you know the condition of the fluid. Brake fluid doesn't 'flow' through the system. That means the fluid down at the caliper could be black, nasty, worn, done for. But the fluid in the master cylinder could be clear! But, if the fluid in the master cylinder is anything BUT clear, then you can bet the fluid at the bottom is really, really past it's prime!

My $0.02.
 

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Mine's two years old and due now, but unless you're able to put a substantial number of miles on it, for most two years will be fine. The car question puzzles me a little two, for starters you have a wheel cylinder or brake caliper that hasn't nearly the airflow across it that bike brakes do and it's hauling something much heavier to a stop which will typically generate more heat. So you have the same fluid in the caliper or wheel cylinder under a more stressful environment for a longer time???? I know in Germany and a few other European countries, part of the vehicle (car) inspection is the brake fluid, if it's not up to par, the car fails.
 

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Mine's two years old and due now, but unless you're able to put a substantial number of miles on it, for most two years will be fine. The car question puzzles me a little two, for starters you have a wheel cylinder or brake caliper that hasn't nearly the airflow across it that bike brakes do and it's hauling something much heavier to a stop which will typically generate more heat. So you have the same fluid in the caliper or wheel cylinder under a more stressful environment for a longer time???? I know in Germany and a few other European countries, part of the vehicle (car) inspection is the brake fluid, if it's not up to par, the car fails.
You'd think, but bigger discs/drums, thicker pads, and the fact that most cars have airflow deflection to at least the front brakes, means that most cars actually don't get as hot as most bikes. Nearly all, if not all, bikes require DOT 4 brake fluid; a higher heat rating. Many cars get away with DOT 3, a lower heat rating! There's also a lot more fluid to absorb the heat. Coupled with 4 wheels instead of two, and bigger brakes? I'd wager there's a good chance that your average disc brake on a car takes less stress than your average disc brake on a bike. ESPECIALLY single disc front bikes. Heck, the front disc brakes on my car have 80,000 miles on them and are still within spec (just checked a couple weeks ago). My bike has 29,000 miles on it and it's on it's SECOND set in the front! That tells me two things. 1) The pads on my bike are much thinner and 2) They get hotter; leading to faster wear (but better performance).

That said; lots of guys go years and years without replacing brake fluid on their bikes. Doesn't mean you should. Reduced performance and component wear exists. Same with a car. It's an often neglected maintenance item, but it's still there. Check your manual! There's a service interval to change the brake fluid in your car, too. I just did mine not long ago. In fact, the car I still drive now is a car I bought my Senior year of high school; had 80k miles on it then (has a little over 200k now). Replaced the brake fluid when I bought it and the brake performance difference between driving it home, and driving it after changing the fluid was night and day.

Just because you got away with something, doesn't mean it was 'good'. Lots of guys run their lawn mowers until they blow up. No oil changes, no blade sharpenings, no belt maintenance. Some guys could have a mower for 10 years like that! Some will lose theirs after two seasons. But one thing I guarantee you; is the old guy on the 1968 riding mower he bought from a sears catalog is NOT one of those guys!

If you get a new bike every few years, don't ride too many miles and don't particularly care about it having peak performance? Go for it! If you plan to hang on to it, don't want to risk needing to do a tedious caliper rebuild, and want the brakes to work their best (not just 'good enough), then change the fluid! Up to you!
 

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Had my trucks original fluid done after 10 years. Mech said fluid was a little dark but not bad. Did my 2006 Yamaha scooters fluid this year myself. A little dark but clear. Seeing how little fluid the bike takes and how easy it was, it should have been done more often.......
 

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Dark colored fluid is a dead give-away that it's degrading, however, that's heat degredation. You won't see the moisture that's allowing the fluid to compress. It's that compression that gives you the spongy feel.Since the fluid's performance degrades slowly, you usually don't notice it until you change it. That said I went 30k miles and the fluid was black as coffee. Really waited too long.
 

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Synthetic based fluid will not dissipate the water like conventional fluid will, in other words you will have water pockets with syn, were conventional will dissipate throughout the fluid. Replace with DOT 4 or 5 and change every two years, no matter what the mileage.
 

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Sorry, but I've never heard of changing brake fluid that frequently. Never too late to learn something new, I guess. However, I've owned numerous autos, two motorcycles, and three riding mowers in my 62 years and I never had brake maintenance issues. All vehicals have been owned for close to 10 years or in some cases longer. I'll agree with the premise and the manufacturers recomendations that for optimum performance change the fluid at their suggested intervals, but I will question how critical it is. Like many have stated, they see no real change in performance after changing their fluid. And finally, yes I'm one of those who has only changed the oil in my current riding mower once in the 10 years I've owned it. Still runs like new. If it aint broke, don't fix it. Right? :eek:
 

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I believe that there is something to be said about experience and old geezers so I tend to perk up when anyone over 60, with years of bike stuff experience, makes a comment on this website.

It is sometimes hard to enjoy riding when I've read some of the threads here with all the advice and suggestions that if you don't do this and don't do that, you'll one day have to thumb a ride. I get enough anxiety just trying to work and do family stuff... please do not add to my anxiety by making me worry so much about fluids and so on!

I believe that most of these guys that visit here care about their scoots and where they ride. Lets please do not go overboard with your ideas of the maintenance schedule everyone should follow. Most of our bikes will eventually be owned by someone else just like our houses, land, and sometimes our wives. :D
 

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Well, I agree that it's unlikely that you'll have a catrosphic brake failure from not changing the fluid. However I did have a front caliper sieze up on my '81 400 Special. The cylinder wall got rusty and the piston failed to return completely. I went into a turn with some sand and gravel on the road and as I accelerated out of the turn, the front wheel slid and I went down fast. I wasn't the first owner so I don't know what the root cause of the problem was, but I cleaned a lot of rust out of the cylinder and it took nearly a quart of fluid thru the system before I got clear fluid.

Do I worry about a repeat of this? No. Do I worry about the condition of my brakes as I'm riding? No. Did I spend $7 and 20 minutes on preventive maintenance for my current ride. You bet I did! Once was enough.
 

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Discussion Starter #15
brake fluid change

So, after reading these replies I became convinced I will do this. Actually it is not really an unpleasant type of job and you will "feel" better after it is done. The reservoir was filled with fluid the color of root beer. Now, I got this bike from a previous owner so I have no idea how long this stuff was in there. Also when opening the bleeder valves some nasty stuff came out there also. YUK! I pumped the brakes, being sure not to let air in, until I got clean fluid. In all honesty, I cannot see a marked difference in performance, but I do feel a sense of having a little more confidence in the braking system now that it is done. The Kawasaki website will allow you to download the owners manual if you don't have one and they walk you through it, as do numerous youtube videos. So for a small investment you will sleep better at night, unless of course you have insomnia, in which case doing this will be as useless as tits on a bull.
 

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Changing it was the right thing to do.

I always get a kick out of stories about "I never did that and look how long my (whatever) lasted."

Well, consider this...how much longer it probably would have lasted if you did "that", whatever "that" is. ;)
 
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