Date: Thu, 12 Mar 2009 01:43:30 -0400
Reply-To: Jonathan Farrugia <jfarrugi@UMICH.EDU>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jonathan Farrugia <jfarrugi@UMICH.EDU>
Subject: Re: home made pressure bleeder
In-Reply-To: <376148.9025.qm@web82704.mail.mud.yahoo.com>
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two considerations that i can think of.
1. you should consider a good dryer for the compressed air if you don't
already have one.
2. brake fluid is an alcohol designed to absorb atmospheric water. this
is the reason that you change brake fluid. the boiling point of the mix
becomes lower after it absorbs atmospheric water. not to mention the
corrosion it causes in the system. normally when you open brake fluid
unless you have another job coming up in the immediate future you should
use the contents of the unopened can and disguard the remainder. that is
because it is going to gain atmospheric water after the seal has been
broken even though it is just sitting on the shelf. therefore there
should be some consideration of whether you want to leave brake fluid in
the bleeder bottle you create or dump it after each bleeding session.
http://en.wikipedia.org/wiki/Brake_fluid
jonathan
On Wed, 11 Mar 2009, David Kao wrote:
> I am going to build a power bleeder that is slightly different
> from all mentioned so far. Since I have a small compressor with
> an air tank of about 10 or maybe 20 gallons I will use it as
> a pressurized air source. I will have a bottle made of hard plastic
> transparent and about 2 liter capacity. There will be two hose
> fittings on the cap. One connected to the compressed air source. The
> other connected to the cap of the brake fluid reservoir cap with a
> fitting on it too.
>
> Internal to the 2 liter bottle one of the fittings will have a hose
> reaching the bottom of the bottle but the other does not have a
> hose inside. This 2nd one will be connected externally to the
> compressor. The 2 liter bottle will be filled with fresh brake fluid.
>
> The air compressor will be set to 10 or 12 PSI and holds it there.
> I hope this bleeder is easier to use because I will not have to
> empty the (pressurized bleeder) after bleeding. The 2 liter bottle
> will keep the remaining brake fluid in it after bleeding. The
> compressor will be free from brake fluids. I can drain down the
> pressure of the air tank before disconnecting the bleeder.
>
> I do have to visit Home Depot for hose fittings. The cost will be
> less than $10 I think since I already have the small compressor.
>
> Has anyone tried this? Will this work? I hope so.
>
> David
>
>
> --- On Wed, 3/11/09, Bob Mac <yakandhike@COMCAST.NET> wrote:
>
>> From: Bob Mac <yakandhike@COMCAST.NET>
>> Subject: home made pressure bleeder
>> To: vanagon@GERRY.VANAGON.COM
>> Date: Wednesday, March 11, 2009, 6:17 PM
>> Has anybody tried the vacuum bleeder sold by harbor freight.
>> It's only $19.95 and seems like a simple operation. No
>> worry about blowing seals and everything is done right at
>> the wheel, except filling the res. Just curious
>
>
>