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Brake Line Pressure--How high is it?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Lazydog, Oct 21, 2002.

  1. Lazydog

    Lazydog 1/2 ton status

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    Hello all, I need to replace the brake line from the Proportioning valve back. I thought about cutting the end off where the bad part is and using a union and compression nuts to attach a new piece. The Cliff Claven here at work says brake line is upwards of 10,000psi, and I should just replace the whole line. I decided to ask the real experts and get your opinions

    Thanks
     
  2. HarryH3

    HarryH3 1 ton status Author

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    I don't know if brake lines will work correclty with a standard compression fitting that uses a ferrule. They are a dual-tube construction. I've never seen a fitting like that on a factory brake system.

    You can buy various lengths of brake lines at any auto parts store, with fittings already installed on both ends. With a tubing cutter and a double-flare tool, they're very easy to modify. /forums/images/graemlins/cool.gif You need to use the correct brake line fittings and double-flare the ends of the brake lines when installing a new fitting. Brake line fittings are a type of compression fitting, but the double flare of the tubing itself is what gets compressed into the fitting and forms the seal. If your brakes fail, you can die. This is NOT a place to experiment or be cheap. /forums/images/graemlins/shocked.gif Do it right and live to tell about it. /forums/images/graemlins/thumb.gif
     
  3. HarryH3

    HarryH3 1 ton status Author

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    Oh yeah, fill out your profile so folks know where you are. Someone near you may be able to help you out! If you're near Colorado Springs, I've got a double-flare tool and would be glad to give you a hand so you and your truck don't end up as a tangled mess somewhere. /forums/images/graemlins/shocked.gif
     
  4. Lazydog

    Lazydog 1/2 ton status

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    Your right about doing it right the first time. That's probably what I'll do. You wouldn't happen to know if the brake line goes from the Proportioning valve all the way back to the Brakes in one solid line? Oh yeah I also updated my Bio, sorry about that I thought it was up to date. Thanks
     
  5. HarryH3

    HarryH3 1 ton status Author

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    It isn't all one piece of line. There are one or two couplers in the line along the frame rail. Trace along it and it's easy to see. /forums/images/graemlins/cool.gif There are a lot of CK5'ers in the Phoenix area, so maybe someone there will pipe up with the correct tools and/or assistance. /forums/images/graemlins/thumb.gif
     
  6. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Your buddy is a little high on the pressure but I still agree with him 100% those parts should not be used in the brake system.
    Disc's line pressure is about 900psi and drums are about 300psi after the proportioning valve. I think the CLAMPING pressure on the disc is somewhere around 10,000 psi and that's probably where he got that figure.
    Use the correct fittings or there are companies that will make you up a set of correct lines.
     

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