Disc brake dilemma.

Discussion in 'Brakes' started by 84 M1008, Dec 5, 2018.

  1. 84 M1008

    84 M1008 Full Access Member

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    Gentlemen, I'm doing a rear disc brake conversion on my 84 K30 along with a dually conversion. There is a dually rim clearance issue with the rear calipers. I don't have the rims yet as I don't know what the inside diameter of a 16 inch dually rim is. I searched but that dimension is not available. The question is does anyone know what this measurement is?
     
  2. ajdemello

    ajdemello Full Access Member

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    I can measure one when I get home if no one has one for ya by then.
     
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  3. 84 M1008

    84 M1008 Full Access Member

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    Thank you sir.
     
  4. nvrenuf

    nvrenuf Full Access Member

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    The inner dia of a wheel can vary based on the material (steel vs aluminum) and also shaped differences from manufacturer to manufacturer (the barrel may be smooth or have small seam-like variations).

    What axle are you using? An SRW 14 bolt? DRW bearing hubs or SRW? What disc kit?
     
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  5. climb-101

    climb-101 Full Access Member

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    my single rear setup with a 14 bolt and dish setup has about 1/4” between the 16” rim and the caliper

    700D7AC8-3D1B-4C77-9C7B-2562026D44CD.jpeg

    4E8588C3-DE32-460E-B25B-2B287AA62482.jpeg
     
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  6. ajdemello

    ajdemello Full Access Member

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    Ok so mine are 15 1/2" at the top. After about 2" they go to 15" and then down to 13 3/4" at the smallest spot.

    20181205_153756.jpg
     
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  7. 84 M1008

    84 M1008 Full Access Member

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    Thank you!
     
  8. 84 M1008

    84 M1008 Full Access Member

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  9. 84 M1008

    84 M1008 Full Access Member

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    SRW 14 bolt, but I haven't installed it yet. It's an East coast gear rear disc conversion kit.
     
  10. nvrenuf

    nvrenuf Full Access Member

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    Disc kits for dually axles typically use a deep rotor and either have a weld on bracket or a bolt on with a heavy offset bent in it. Clearing the inner dually wheels is why 1 tons have a "longer" drum and the springs set closer to the frame (issue #2?). Grinding calipers to clear wheels is relatively common on rear disc or when using smaller dia wheels, since you're using a combo that really isn't designed to be used together you might have to do this IF you can go far enough without ruining the caliper.

    Back to potential issue #2, have you mocked up the wheel / axle assembly under the truck or measured for clearance? Dually wheels on an SRW truck may hit the leaf springs.
     
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  11. 84 M1008

    84 M1008 Full Access Member

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    I'm going to get new wheels once I find out if I have the proper clearance. I'll get a 16 inch wheel from the scrapper to mock it up and see what I got. This truck has huge brake drums on it. It almost looks like a dually axle with SRW hubs on it. Idk
     
  12. nvrenuf

    nvrenuf Full Access Member

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    Yeah the 14 bolt drums are big but, believe it or not, D70HD (OE pick up dually axle) drums are a good bit bigger.
     
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  13. climb-101

    climb-101 Full Access Member

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    1/4” is miles of room when doing fab work. lol. i do have 17” ones going on the truck once i find some 37” tires i like.
     
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  14. 84 M1008

    84 M1008 Full Access Member

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    I just scored 6-19.5 dually rims for my truck with the 8 lug 6.5 pattern. I'm taking the 37's off because replacing them is just too expensive, and with the 6in lift it has it would look stupid with little wheelbarrow tires on it. discountdieseldepot has them available on eBay if anyone is interested.
     
  15. ajdemello

    ajdemello Full Access Member

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    Why 19.5s? Seems like it would be a hard tire size to find at least used.
     
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