Brake Fluid ??'s

William K Denton wkdenton at
Sat Nov 10 11:28:16 PST 2007

Real simple guys... DOT 3, 4 and 5.1 are glycol based hydraulic fluids, 
which, regardless of whether or not it's synthetic, is hygroscopic, aka it 
absorbs water.  Boiling point is not an issue unless you're racing for two 
reasons... #1 - you will never get anywhere near the (dry) bp of either DOT3 
or DOT4 under normal street riding conditions, even if you're strafing 
you're favorite mountain pass, and #2 - once the brake fluid begins to 
absorb water, the boiling point goes down anyway to the point where DOT3 and 
DOT4 boil similar temps +- ~30ºF.

DOT 5 is silicone.  It does not absorb water.  Any moisture in the system 
will pool at the lowest point, usually in your caliper.  Unless you store 
your mc indoors in the desert, I would not use it.

Here's an article that you may find enlightening...

Bill in Yardley, PA
wkdenton at
'96 GPz1100

----- Original Message ----- 
> ----- Original Message ----- 
> From: "Paul Landry" <p_landry at>
> To: "'Kawasaki GPZ1100 discussion'" <gpzlist at>
> Sent: Saturday, November 10, 2007 12:19 AM
> Subject: Brake Fluid ??'s
>> Ok..  I have not personally done a brake fluid change in a while.

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