Big truck air horns on small truck

Discussion in 'Trucks and Trailers' started by 75, Feb 17, 2001.

  1. 75

    75 LawnSite Senior Member
    Posts: 992

    I've always liked the sound of big truck air horns (especially during the 3-1/2 years I drove them!) but always felt they looked too big on a pickup. They're also pretty hard to fit under the hood, especially a pair. (First place I thought of putting them) Trying to decide where to put them on my '75 GMC, I found plenty of space under the cab. I mounted one directly to each frame rail, drilling holes ("Measure twice, drill once!") and bolting as required. An alternative would be to build brackets off the frame and bolt to these, to avoid having to drill a fairly large hole to clear the fitting joining air line to horn. Inside the cab, in the hollow area behind the door striker bolt, I mounted the air valve to operate the horns, running a length of small cable up inside the cab, out through a hole I drilled just below the roof on the inside wall (I drilled through the interior trim piece and the cab at the same time, then removed the trim piece and used one of the chrome trim rings that go around the door lock knob hole (stolen from a spare door panel) to give it a "finished" appearance) and connected the end of the cable to where the visor attaches. Now just run air lines from your supply to the valve & horns (I use an old A/C pump as my onboard compressor, with a storage tank mounted between the frame rails up front) and people may not be able to see 'em, but they'll sure hear 'em!

    1975 GMC C-35
  2. Randy Scott

    Randy Scott LawnSite Bronze Member
    Posts: 1,915

    Those should be able to rattle the windows in a Geo!
  3. cat320

    cat320 LawnSite Senior Member
    Posts: 822

    So what kind did you get and how long did it take you to install them?
  4. 75

    75 LawnSite Senior Member
    Posts: 992

    I used "Genuine Mack Parts" because the company I drove for at the time used all Macks. Bolting them onto the frame took a few hours, largely because I was learning as I went. The plumbing was a little more tedious, so I'd say in total a weekend is plenty of time to get everything done. And they're great for rattling Geo windows, especially when the driver is too busy doing their hair to notice the light's green!

    1975 GMC C-35
  5. snow

    snow Banned
    Posts: 114

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