Date: Thu, 1 May 2014 09:38:52 -0400
Reply-To: Mike B <mbucchino@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike B <mbucchino@CHARTER.NET>
Subject: Re: Brakes- the saga continues
In-Reply-To: <CAHTkEuKN9HtM7-7UgdN-bPm_s33CjZmRxB7dt-Xnnw4R6sK_Bg@mail.gmail.com>
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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 a second of inattention to
> allow a bit of air to enter the hydraulics...a very very small bubble of
> air anywhere in the system will cause the spongy brake pedal feel..
>
> Another symptom you may be encountering here is warped rotors,
> oscillating as the wheel turns, a wobble that pushs the brake pistons way
> back into calipers. So rather than an actual 'soft pedal' from air in the
> system, you may be needing to give the brakes a few pumps to move that
> brake pad back to where it will actually grip the warped rotor...
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