What size brake front-to-rear-brake line?

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by NorthJersey, Oct 17, 2011.

  1. NorthJersey

    NorthJersey New Member

    I have a rusted out front-to-rear brake line on my 2000 1500 4x4. The line is so rusted and swollen, I can't really tell what size I'm dealing with. Does 1/4" sound right? I know this is a long shot, but does anyone have a length measurement for that line?
  2. Caddiac

    Caddiac Epic Member 5+ Years 1000 Posts

    You might want to use GMPartsdirect.com. They can use your vin # to price you the correct line. There may be some information as to the line size in the part description.
  3. NorthJersey

    NorthJersey New Member

    I don't think I ever got a response from GMPartsdirect.

    I wonder if anyone has any idea what size nut this line uses, particularly where the line connects to the ABS modulator valve.


    Since the line from the modulator valve to the rear uses the far right port on the top row, I had no clearance for a line wrench or a crows foot wrench. I had to cut the line and use a 9/16 socket to remove the flare nut. The nut size (confirmed with a caliper) is 1/2-20. The brake line measures 1/4" coming out of the ABS modulator valve.
    Last edited: Oct 28, 2011
  4. 99monguse

    99monguse Rockstar

    It is 1/4 line...these trucks are notorious for lines rotting out especially by the l/f wheel
  5. NorthJersey

    NorthJersey New Member

    Yeah, I just popped a line near the driver's side wheel.
  6. NorthJersey

    NorthJersey New Member

    Fortunately, this one is easily accessible. The port on the abs module that corresponds to the line coming from the rear of the master cylinder(closest to the driver) is on the bottom left. Once again, the nuts are 1/2-20 (9/16 line wrench). I just buy the preflared PVF coated sections and put an adapter at each end. You'll need two 7/16-24 to 1/2-20 adapters (Poly Armour part no. PAA-S420), two 7/16-24 unions (part no. BLU-4B), and one 60" piece of 1/4" brake line (PAX-460) for the lines running from the master cylinder.
  7. ponjohn

    ponjohn New Member

    Hi Guys-

    I don't post much but returned to research brake lines.

    I own a 99 Suburban (OBS), brake line burst this morning while towing...not good. It is the one running along DS frame rail to the back.

    Is there a way to buy the parts without using adapters or unions?
    In a perfect world I would like to have it appear not fixed.

    I may do some of the other lines too.


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