Date:         Fri, 12 Jan 2007 05:40:22 -0500
Reply-To:     Edward Maglott <emaglott@BUNCOMBE.MAIN.NC.US>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Edward Maglott <emaglott@BUNCOMBE.MAIN.NC.US>
Subject:      Re: bleeding bloody brakes
In-Reply-To:  <D3E0887D-FF48-49B3-BB61-81770E4432B1@VERIZON.NET>
Content-Type: text/plain; charset="us-ascii"; format=flowed

I think there is a situation in the rear brakes that can cause this
symptom.  something about hardware installed backwards or incorrectly.  The
fact that backing up causes the situation for one pump, then it is firm
again tells me that something it putting a big gap between the rear shoes
and drum.  If it was air, it wouldn't get firm again.

Possibly master cylinder seals, but they usually cause a slow sinking pedal
when holding pressure on it.

Edward

At 10:35 PM 1/11/2007, Matthias Kuster wrote:
>Hi list,
>
>I am looking to get some input on my brakes for a 1984 Westy:
>
>I have replaced front calipers, rear slave cylinders, installed new
>pads in the front and left the old shoes in the back (plenty of meat
>on them). I have also replaced the master cylinder and reservoir. I
>have checked whether the servo holds vacuum-yes it does, as well as
>the line into the engine bay. have replaced one way valve as well.
>The rear adjustment nut is turned until the wheel does not spin
>freely anymore, off the ground, then backed off. I have done this
>multiple times also.
>
>I have bled the system now the 7th time with a pressure bleeder at 20
>psi, starting at RR, RL, FR then FL wheel, and bled at least 500 ccm
>at each wheel (according to Bentley) each time. There don't seem to
>be leaks, at least my reservoir is not going down, ie I'm not losing
>fluid. I have also done it just with the pumping method once, with a
>hose attached to bleeder screw and submersed in liquid.
>
>Once I am done, while still at standstill, the pedal feels firm. Then
>I get on the road and all of a sudden there is greater travel for
>maybe one pump of the pedal, but only when I move from a standstill,
>ie change gears from reverse to 1st especially, or pull into a store,
>then come out and start driving, swoosh, one entire push of the brake
>pedal and hardly anything happens, very little brake action. The next
>pump and the brakes are firm again. This happens especially if I back
>up a bit, and is a real PITA when parallel parking.
>
>What am I doing wrong?? I also tried pumping while pressure bleeding.
>Only thing I have not tried is keeping pedal depressed while closing
>bleeder screws. Maybe I am somehow sucking air back in, even though
>the pressure bleeder is still at 20 psi and attached to the reservoir.
>
>Other option could be faulty parts, especially the master cylinder. I
>cannot 100% confirm that I am not losing brake fluid somewhere (leak)
>and suck air back in. But I do not see wet areas anywhere around the
>lines and junctions.
>
>Could this be the brake regulator?? Could it be because of my lines???
>
>Any help appreciated Volks!!
>
>Keep on trucking
>
>Matthias