Date:         Mon, 15 Dec 1997 08:09:07 -0700
Reply-To:     "Michael A. Radtke" <m.radtke@ELM.AZ05.BULL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.sdsc.edu>
Comments:     RFC822 error: <W> CC field duplicated. Last occurrence was
              retained.
From:         "Michael A. Radtke" <m.radtke@ELM.AZ05.BULL.COM>
Subject:      Re: Air in Brake Circuit
Comments: cc: Tim Smith <smitht@unb.ca>

Thanks, all of you who responded to my note.

I have not gone back to the problem yet, but I have spent some time considering what you all have written.

1) Bleeding.  The technique that I used was two person:

   a) Hose from bleeder into jar with some brake fluid in it.  The hose
      below the surface to show bubbles, and to stop air from entering.

   b) Open bleeder / depress brake pedal / close bleeder / slowly release
      brake pedal.  Repeat ...

   I do believe that pressure bleeders and other such aids offer
   convenience, but I can't see how they would be an improvement over my
   technique as far as effectiveness or reliability.

2) Bench bleeding.  Well, this is a weak spot, I must admit.  I did a
   minimum of this before I installed the master cylinder just to lube the
   parts since the fluid leaks out anyhow.  I didn't re-bleed the master in
   the car either since plenty of fluid was being pumped.  Both the rear
   and front circuits pumped out all the old discolored fluid and got to
   new clear fluid.

3) Air leak.  I have no doubt that there is an air leak.  The problem is
   that I can't figure out just where.

   I will wet the reservoir connections with brake fluid to see if the leak
   is there.

   Any other air leak that I have has to act like a check valve.  I have no
   fluid leaks.  Yet the front system is full of air.  Perhaps another
   clue.  If I pump the pedal a few times and then release it, I definitely
   can hear sound from the master cylinder of air squirting around in
   fluid.

   Both front wheels act exactly the same.  If one slave cylinder was
   admitting air, wouldn't one bleed differently from the other?

In summary, I do believe that my brake bleeding technique is OK.  What I
need is advice on how to find the air leak.

Still asking for help,
Mike


Michael A. Radtke  -  Z74               Voice: 602-862-4897
Bull                                      FAX:         4853
13430 N. Black Canyon Hwy.
Phoenix, AZ  85029                      Email: m.radtke@bull.com