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OT? : brake line vs hydraulic line

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  • OT? : brake line vs hydraulic line

    Can steel brake line for vehicles be used for power steering hydraulic line (high pressure side)?

    What's the max pressure for the brake system vs the pressure for power steering hydraulic line?

    Also, is it considered strong enough to braze these lines instead of using fittings?

    These are just theoretical questions since I don't intend to do any of these for safety reasons.

  • #2
    It depends. Some brake line hoses have a max pressure rating of 3000 PSI.


    • #3
      Brake line tubing is leaded steel that is what makes it bend so easy. I am not sure what the pressure rating of brake line tubing is. You can not weld it or braze it because it will fall apart like heating aluminum tubing.

      Here is the information on schedule 40 and 80 and 160 steel pipe. You can weld this and you can buy weld on fittings.
      Last edited by gary350; 07-30-2010, 11:10 PM.


      • #4
        In an off road -non DOT situation , I would think that brake line (steel tube) and power steering line (steel tube) would be universal. If it is going to be an on highway vehicle I would only use a direct replacement part.



        • #5
          There's a nice tube chart on this suppliers site.


          • #6
            About the most power steering relief valve pressure pressure you will encounter on a heavy vehicle is about 1400-1600 psi.
            Doesn't matter if it's a pickup or a Kenworth. The typical car usually has about 2-300 psi less, the main difference is the amount of flow or gpm between small and large vehicle pumps.

            Brake systems usually operate at about 800-1000 psi and upwards of 2000 psi under extreme conditions.

            So although I believe brake line tubing is up to the task of the pressure, I have my doubts that it can provide the necessary flow, unless of course the tubing is adequately sized.
            Home, down in the valley behind the Red Angus
            Bad Decisions Make Good Stories


            • #7
              Originally posted by gary350
              Brake line tubing is leaded steel that is what makes it bend so easy.
              I've never used steel brake line on a vehicle. I don't think the usual stuff in the UK is leaded, it's damn hard to bend.

              Some people use copper, but I'd worry about workhardening and cracking. I've always used Kunifer (copper-nickel) which has a 20 year corrosion warantee.

              Seems it's also known under a few other names;
              Paul Compton


              • #8
                Standard parts store 3/8" brake line will hold in excess of 3,000 PSI in both the coiled stuff and the straight lengths. I tested it with the standard 45° double flare and brass fittings. Might have been able to get more on it but my gauge topped out at 3K.