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will it work?

Discussion in 'Brakes' started by robert ruggles, Apr 5, 2021.

  1. robert ruggles

    robert ruggles Junior Member

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    First Name:
    Robert
    Truck Year:
    1981
    Truck Model:
    C10
    Engine Size:
    5.0
    I bought a 1981 C10 short stepside with 2" lowered spindles and I wanted it back to stock height.
    The lowered spindles had 1' disc brakes and the only stock height spindles I could find use 1.25 disc brakes which I have installed and it looks so much better with the C10 sitting level instead of nose low. I have ordered new 1.25 calipers and rubber hose lines that fit 1.25 calipers. I have 11" rear brakes.
    Will the change to 1.25 disc brakes up front work out ok with my rear brakes? I included a picture of the MC and booster.
    Thank you for any help

    0405211258.jpg

    0403211440a.jpg
     
    Last edited: Apr 5, 2021
    ali_c20, WFO, bucket and 5 others like this.
  2. Curt

    Curt Supporting Member Supporting Member

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    Nice truck
     
  3. Blue Ox

    Blue Ox Turning Diesel Fuel Into Fun

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    I @$$ume you're referring to the thickness of the rotors.

    The rotor diameter and piston size will have the most effect on the braking. As long as the calipers fit correctly and the other factors are the same I doubt you will notice anything different. Except the extra rotor meat may help with heat dissipation.
     
    bucket likes this.
  4. 78C10BigTen

    78C10BigTen Full Access Member

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    Good lookin stepper!!
     
  5. Shorty81

    Shorty81 Baby Boomer

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    Welcome from the Buckeye State. Looks great raised up where it should be!!
     
  6. Craig 85

    Craig 85 Full Access Member

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    Main thing I would check is to see if the different rotor set ups use the same master cylinders. The bore size could possibly be different.
     
  7. Ken B

    Ken B Supporting Member Supporting Member

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    So that's what my truck is supposed to look like....even the same brown color...
    Mine was rusted and now in pieces...
     
    Blue Ox likes this.
  8. Keith Seymore

    Keith Seymore Full Access Member

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    Here's the brake system release chart, showing the parts by part number for the entire system. You can see JB3 is the smallest power brake system, with the 1" rotor, and JB5 is the high runner (in terms of production volume) with the 1.25" rotor. JBx = vacuum; JDx = hydraboost.

    I'm attaching the '86 version, because it's what I already have scanned, and the print on the '81 is super super tiny. I would suspect they are very similar if not exactly the same otherwise.


    86 brake chart 2.JPG

    K
     
  9. Keith Seymore

    Keith Seymore Full Access Member

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    The differences I see are a slight diameter difference in the rear brake cylinder diameter, and little difference in the split point and slope of the prop valve.

    I don't think we'll know until you try it.

    K
     
  10. robert ruggles

    robert ruggles Junior Member

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    Thanks for the info. I am talking about the rotor width. I will report back the results when I get the new calipers installed.
     
  11. ali_c20

    ali_c20 Full Access Member

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    Welcome from Austria. I think there's not much difference. Best way to find out is road test on a quiet stretch of road.
     
  12. Raider L

    Raider L Full Access Member

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    @robert ruggles,

    The 1.25 rotors are fine, and I don't know when GM changed over to 4 disc brakes and got rid of the drums but My '74 full size has 1.25" rotors in front and 11" drums in the rear. You've got a very nice little truck. If you take care of that thing it ought to last nearly forever. What's the interior look like? We like pics around here! Don't go showin' us a nice truck like that...from across the dang street...makin' us squint.

    And do you know how hard to find those hub caps are? I had them on my truck for a short while and I think I sold them for ten bucks. Now I wish I had kept them. I bought them from a wrecking yard and they were in a box. They looked new. Yours as far as I can tell look pretty dang good.

    @ali_c20,
    How prevalent are American pickup trucks in Austria? Who buys them? How much do they run $$? What years do people want over in Europe? Who drives them,i. e. farmers, regular people, just men, who?
     
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  13. Raider L

    Raider L Full Access Member

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    @robert ruggles,

    Oh yeah, why is your brake res. crooked? It's actually turned like that, it's not supposed to be straight up and down?
     
  14. ali_c20

    ali_c20 Full Access Member

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    American pickup trucks are pretty rare in Austria / Europe old and new.
    The old ones are driven by enthusiast and are used for weekend cruising. Buyers are 98% men. The most sought model years are the late 50ies to early 70ies short beds form all manufacturers. The price depends on mileage, condition, etc. It can vary from 10k to 30k $. When buying a truck from the states you also have to consider shipping, taxes and fees for registration. This can easily cost you additional 7-10k $. Best is if they are unrestored and not modified. We unfortunately have very strict rules for historic vehicles so every change of the original car/truck can void your registration.

    New trucks: I only have the price for the new Ram 1500 Sport it's ~73k $. But thanks to the environmentalists on 1st of July there will be a new tax for co2 emissions and the same Ram will cost ~110k $. Some are used for work and towing but most of them are toys.
     

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