Repairing steel a/c line

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Dwight Goertzen, Feb 7, 2026.

  1. Dwight Goertzen

    Dwight Goertzen Bobtail Member

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    Hello i have a pin hole in my a/c line on my truck. It is a steel line. I would like to just braze it since a new line from peterbilt is almost $400. Ive read some about flowing nitrogen through it while brazing. Is this a must? Or can I just simply braze the hole shut and call it a day?
     
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  3. AModelCat

    AModelCat Road Train Member

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    I would advise against it. We had a guy almost light a machine on fire doing just that. R134a is said to be considered non-flammable but do you really want to chance it? Are you certain someone didn't put something else in there at one point? Remember you also have oil inside those lines as well.

    My advice either pull the line and flush it if you want to braze it or put a new one on.
     
    Last edited: Feb 7, 2026
  4. bad-luck

    bad-luck Road Train Member

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    It won't last, bite the bullet and buy a new one
     
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  5. Rideandrepair

    Rideandrepair Road Train Member

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    I had one welded on my Buick once. Later found a new one at a reasonable price. Lol. It worked. Had a/c lines made for my Semi. They welded female thread fitting to the compressors fittings. Screw new a/c lines into the re usable ends. Great way to save $$$. I can get a new line made at very reasonable prices. Make my own using re usable fittings.
     
  6. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    If you remove the line, and can braze very well, it'll dahm sure hold. No need for nitrogen

    Since you're here asking though, that says to me you're not good at brazing
     
  7. Dwight Goertzen

    Dwight Goertzen Bobtail Member

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    Thanks for the input!
     
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  8. Rideandrepair

    Rideandrepair Road Train Member

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    IMG_6392.png IMG_6393.png
    Been working good for about 10 years now. All hoses are the same diameter, unlike originals. Still works fine. Ran straight rubber hose to bunk also. They wanted $1200 back then for original rubber/metal lines. Picture is when the expansion valve was stuck. Best part is being able to fix them yourself if one gets chafed. Make them a bit long, in case an end gets weak. Most vulnerable place. Just cut off a few inches.
     
    Last edited: Feb 7, 2026
  9. W923

    W923 Road Train Member

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    Brazing will certainly work
    We have brazed hundreds if not thousands of lines and custom fittings/adapters some were low pressure suction lines others hydrostatic transmission lines that regularly see 5000 psi
    Never had one fail
    Most older style hydraulic fittings were made with brazing as well
    The only reason for nitrogen is probably to keep scale from forming inside when it’s red hot
    We run mig gas though them….anything to keep the oxygen away from the red hot steel
     
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