Date:         Sat, 14 May 2016 10:59:19 -0700
Reply-To:     Neil N <musomuso@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Neil N <musomuso@GMAIL.COM>
Subject:      Re: Home Made Brake Pressure Bleeder: *might* add moisture to
              brake fluid?
Comments: To: David Beierl <dbeierl@attglobal.net>
In-Reply-To:  <201605140927.u4E9RmiO017144@mail14c45.carrierzone.com>
Content-Type: text/plain; charset=UTF-8

Part of my thinking was that since the air was being applied under pressure,
it might impart more moisture. But then people have been using these types
of DIY pressure bleeders for a while now and if I'm not mistaken, the Motive
bleeder is the same type.
I'm googling this, but is the 1016 bleeder tool Bentley manual shows
a fluid type pressure bleeder? i.e. does it draw new brake fluid through those
hoses and push that into the brake reservoir?
If it does, this is also what made me curious. Well that and rust
starting fairly
early in newer brake master cylinder.

images of that MC:
http://tinyurl.com/hqps8k7
http://tinyurl.com/j6w6e7f

But then as Bentley notes, fluid should be changed every 2 years.
Since the vehicle this
MC was in sat unused for the better part of a year, that was probably
what caused
the issues with that MC.

Neil.

On 5/14/16, David Beierl <dbeierl@attglobal.net> wrote:
> At 05:27 PM 5/13/2016, Neil N wrote:


>>When using a home made pressure bleeder to pressurize the brake fluid
>>reservoir with AIR
>>when bleeding the brakes, would this air add moisture to the brake fluid?
>
> That would depend how much moisture is in the air, wouldn't it?  The
> higher the humidity the more water the fluid will absorb.  The fluid
> is hygroscopic (possibly the new synthetic ones aren't) so it will
> actively pull moisture from the air (just as salt will do at high
> humidities) but it's not an instant process.  Speed depends on how
> much surface is exposed to air as well as the concentration of water
> vapor and the pressure.




--
Neil n

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