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  1. #1
    Jr. Apprentice
    Join Date
    Sep 2007
    Albuquerque, New Mexico

    Default Air in brake lines will not go away.

    2001 Suburban 2500 All Disc brakes.

    I have air in my brake lines only on the left front and left rear.

    I installed new brake pads all the way around the truck. I bled the brakes when I was done with a vacuum bleeder. I noticed this problem is with left front and left rear brake lines having air in them. So I figured I would try a different bleeder. This time I used a bleeder that goes on the brake reservoir ; still the same problem. No matter what bleeder I use or what sequence I bleed the brakes, there is still air in the brake lines on the left front and left rear only. The front left get allot of air, more than the left rear. The other side, right front and right rear are fine with no air in the brakes lines.

    Last year I had this problem before. This was after a shop installed a new master cylinder. My brakes seemed mushy after this. The manager said this is normal. Well I did bleed them myself a week after this install and had this same problem.
    I never seen so much air bubbles come from a brake line .It just don’t stop no matter how much I bleed the brakes. So I’m wondering if this shop installed a bad master cylinder or there is bad seal in the master cylinder or they forgot to bleed the master cylinder.

    Any input on this situation would surly help. My truck does brake better, but still kind of mushy.
    Last edited by stevenje98; 07-01-2010 at 12:32 AM.
    2001 Suburban 2500 4x4 6.0L

    2005 Sikorsky U.S Army BlackHawk. Lots of Factory Options installed. no heated seats.

  2. #2
    TrailLeadr's Avatar
    Join Date
    Jun 2005
    Coventry, Rhode Island


    You either have a bad seal, one of your fittings is loose or cross threaded, or you have a bad line somewhere else that air is entering from.

    I would check the fittings around the master. see if they're loose or cross threaded first.
    Rhode Island

  3. #3
    Legend kgibson181's Avatar
    Join Date
    Jul 2009
    Cedar Grove, NC
    Blog Entries


    Yeah if you've tried all of those bleeding techniques then its definately a bad seal or fitting somewhere. Tried just doing a simple gravity bleed yet?

    2003 Silverado 1500
    V8 4.8L 294ci
    2 inch Pro Comp Leveling Kit
    3 inch Rough Country Lift
    33 inch Nitto Terra Grapplers
    5% Tint All Around
    2 12" Kenwoods

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