Date: Fri, 2 May 2014 15:01:39 -0400
Reply-To: William Monk <billmonk@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: William Monk <billmonk@GMAIL.COM>
Subject: Re: Brakes- the saga continues
In-Reply-To: <CAHTkEu+eDQybeJznZ_pUjdofwH4HNndjxm5HzJKKUZdkrtGNzw@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
The first press being soft can also mean that the rears are not adjusted
correctly. Pull the e-brake up a click before stepping on the brakes and
see if it goes away.
Bill
Groton,CT
On Thursday, May 1, 2014, Don Hanson <dhanson928@gmail.com> wrote:
> OK a trick I learned at the racetrack....Use different colors of fluid
> when you bleed the brakes to be assured you've purged all the old dirty
> contaminated fluid....I use ATE Super Blue and ATE (the normal gold colored
> stuff) , alternating each time I change the brake fluids.....
>
> When you see the other color coming out of the bleed tube you can be
> assured you have completely done the job.....but....if you are sloppy with
> any part of the job air can sneak into the lines behind the new fluid and
> you will again have 'soft pedal'.....
>
> I musta bled my brakes a few thousand times when I raced my Porsche
> because when racing, your brakes will get you more 'passes' than hundreds
> of horsepower....and ever the Big Red Brembo super effective hollow
> perforated disc brakes on the Porsche were not immune to boiling the brake
> fluid etc...
>
>
> On Thu, May 1, 2014 at 8:01 AM, Alistair Bell <albell@shaw.ca> wrote:
>
> > I can't comment on compressibility of fluid with large bubbles versus
> > micro bubbles of air, but I do know that brake fluid does , or can, have
> > air dissolved in it.
> > Not to be confused with bubbles, which is entrapped air.
> >
> > Alistair
> >
> > > On May 1, 2014, at 7:23 AM, Gnarlodious <gnarlodious@GMAIL.COM> wrote:
> > >
> > > One big advantage of the vacuum method is that microscopic bubbles
> > > expand under vacuum, causing them to flocculate faster and rise to the
> > > top sooner. I've noticed with pressure bleeding it can take some time
> > > to get microscopic air out of the system. If you watch fluid through a
> > > clear tube you see cloudy brake fluid coming out under pressure, but
> > > that just means microscopic air bubbles are incorporated in the fluid.
> > >
> > > As a wild guess, I would say that one large bubble has more
> > > compressibility than a million small bubbles totaling the same volume
> > > of air. That would explain why your Vanagon's brakes feel fine
> > > immediately after bleeding but a few days later they are all squishy.
> > > This has happened to me several times and is something of a mystery.
> > > Someone more versed in physics could dig up the facts, I nominate
> > > Alistair Bell.
> > >
> > > -- Gnarlie
> > >
> > >
> > >
> > >> On Thu, May 1, 2014 at 7:38 AM, Mike B <mbucchino@charter.net> wrote:
> > >> Regarding the brake bleeding process. It all depends on you method
> used.
> > >> If you use a Motive pressure bleeder, it's a simple one-man process,
> > >> and it's hard to "do it wrong".
> > >> If you use a vacuum hand-held, hand operated brake suction device,
> > >> you need to grease the threads of each bleeder to prevent suction of
> air
> > >> through the threads, but otherwise, it's also pretty hard to "do it
> > wrong".
> > >> If you do it the old-fashioned 2-man way, there's a way to do it
> > >> wrong and a way to do it right. The right way to do it is to attach
> an
> > >> 18" rubber hose to the bleeder and put it in a small plastic or glass
> > >> jar with a inch or so of brake fluid in it. (you could also buy a
> '1-man
> > >> brake bleeder' tool, which is basically this). One guy does the pump
> > >> and hold on the pedal, while the other guy opens the bleeder and
> watches
> > >> the fluid/ air squirting into the jar. Repeat on each wheel until
> > >> there's no more bubbles, being sure to stop every so often to check
> that
> > >> the reservoir isn't getting too low. Use 3 sharp quick pedal strokes
> to
> > >> force air from all of it's hiding places, then hold until instructed
> to
> > >> let go by the guy manning the bleeders. Start at the farthest away
> > >> (right rear), then move to the next farthest bleeder (left rear), then
> > >> right front, then left front. You may need to go around them two or
> > >> three times to get it all, and a hard pedal with no squishiness is an
> > >> indicator that you're done. Be sure to do enough to clean all of the
> old
> > >> dark fluid out and replace it with fresh clear fluid.
> > >> If you do it without the jar and hose, you will make a mess of
> > >> spilled fluid everywhere (it eats paint!), have lots of problems (like
> > >> Don mentions) and depending on your methods and procedures, you may
> not
> > >> be able to get every last bubble of air out of the system.
> > >>
> > >> Mike B.
> > >>
> > >>
> > >>> On 5/1/2014 9:17 AM, Don Hanson wrote:
> > >>>
> > >>> Squshy brakes: Bleeding the system carefully should stop that.
> > >>> "Carefully" being the operative word...Brake bleeding is intolerant
> of
> > >>> sloppy or slipshod work....any lapse at all during the brake bleeding
> > >>> process can render the whole procedure a waste of time...It can be a
> > >>> tedious job, relatively simple in concept but one that demands you
> > make no
> > >>> mistakes along the way...It takes a fraction of
--
Sent from Gmail Mobile
| 
