When the brake fluid is an unknown

I need to add some brake fluid to the front on my KZP.. it got low somehow and what's left in there looks a little murky. So my questions is...

When you don't know if you have DOT 3 or 4 or 5, what do you top it off with? I know you're supposed to not mix types but I haven't owned this bike since it was new so I have no idea what's in there.

Mike

Use Dot 3. The numbers are a boiling point.
Dry Boiling Point Wet Boiling Point
DOT 3 205°C (401°F) 140°C (284°F)
DOT 4 230°C (446°F) 155°C (311°F)
DOT 5 260°C (500°F) 180°C (356°F)
DOT 5.1 270°C (518°F) 191°C (375°F)

del

flush it all out and start over;)

wireman wrote:

flush it all out and start over;)

I agree.
Brake fluid isn't expensive enough to chance having a problem stopping your bike in an emergency situation.

First off though, I'd try to figure out why "it got low somehow". Auto manufacturers used to recommend flushing and replacing the brake fluid in your car/truck once a year. Being that most folks don't rack up as many miles annually on their bikes, I figure the frequency of swapping the fluid out can't be to far off that yearly mark.

Piece of mind is cheaper (and less painful) than a piece of missing/ground down flesh. :whistle:

del

wireman wrote:

flush it all out and start over;)

Don't forget the rear. El-Cheapo store brand quart bottle is enough for both. Should be changed once a year. Buy some fuel line to fit the nipples and use a couple of clean glass mayonaise jars. Once you've gone through what looks like enough to have filled and emptied the system once, switch jars. When it's as clear coming out as it is going in, you're done.

i just read a good article on DOT3/4/5 yesterday:

www.motorcycleproject.com/motorcycle/text/cows-brakefluid.html

if it were my bike, i'd proceed on the assumption that it's not DOT5, cause the bike is relatively new, after the DOT5 drawbacks were known. if it was a new cop bike, i'd also assume it was serviced in accordance with the OEM recommendations which i assume are not DOT5. finally if the recommended brake fluid type is stated on the master cylinder cap, i'd assume that's what's in the system right now.

if it was an older street racer bike, i might be more cautious.

if possible, another option is call the prior owners.

all the dot 5 I have seen is a blue color, I would drain clean and put dot 5 in, it dosent eat paint dosent absorb water, plus the boiling temp is high, I change it out in my bikes first chance I get

Since it is an already filled system I'd stick with DOT4. Most times I hear guys get away with flushing and staying with DOT 5 and saying they never have issues. The reports tell you what can go wrong if you mix them and I just don't care to gamble. Some of the other properties of DOT5 don't seem too good to me for a daily rider so that's why I have never switched.

It's a daily rider I asume and since you should only need to flush and fill once a year I wouldn't worry too much about switching to DOT5.

I'd be more concerned about the sudden drop in the fluid level.

I flush mine each start of the riding season when I do the first oil and once over on the bike.

Post edited by: KZ_Rage, at: 2006/11/20 20:09

A question about brake fluids.

I have Dot 5 in my 650 front and back at the moment. Have had it for years.
I have just bought a GSXR footpeg set up (haven't recieved it yet), and was wondering about this brake fluid stuff.
If I need to switch to a Dot 3 or 4 because the GSXR resevoir uses that, how do I flush out all the Dot 5 in my line and caliper, as I don't want to mix the two?

I put dot5 in all my motorcyles way back in the mid 80s and have had zero problems. The way I flush brake fluid which I'm sure is not by the book, is to pump out the old fluid until the master cylinder is 95% empty, then fill with dot5, pump until 95% empty again, add dot5. Do this until dot5 can be seen coming nice and clear (or blue) out of the caliper. Flushed and ready to go and no fighting bleeding the lines. Never had a problem of any kind doing this procedure. Of course as pads wear, more brake fluid is used to take up space in the caliper to keep the pads adjusted, so this may explain why the fluid has gotten lower.