Front Disc Brake Tutorial

Discussion in 'Early CJ-5 and CJ-6 Tech' started by Focker, Oct 9, 2015.

  1. May 18, 2016
    jpflat2a

    jpflat2a what's that noise?

    Riverside CA
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    I'm showing pictures of components needed for a D30 drum to disk swap, using factory Jeep parts.
    These are the D30 disc brake components from a 1976 thru mid 1978 CJ model using 1-1/8" thick rotors; this also utilizes 6 bolt locking hubs or drive flanges.
    If you had a 1972-1975 drum brake set-up, this is what you would need to convert.
    Of note are the factory wheel hubs; notice the backside factory machining for the mounting of the rotor on the inside of the wheel hub.
    Also note the often referred " 6 bolt" caliper mounting bracket and dust shield.
    The last picture shows assembled view more or less for reference.
    If you are junking a yard, then you can see the component part numbers and compare.
    I know this is for D30 conversion; maybe the wheel hubs and other parts would work on closed knuckle design as well. Do your own research.
    Hope this helps someone.
    Moderators move it out of here if you desire. IMG_0949.JPG IMG_0950.JPG IMG_0951.JPG IMG_0952.JPG IMG_0953.JPG IMG_0954.JPG
     
    Danefraz likes this.
  2. May 18, 2016
    Focker

    Focker Rust Never Sleeps Staff Member Sponsor

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    Great pile of metal...Makes me drool!
     
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  3. May 26, 2016
    shaun

    shaun Member

    ohio, Beavercreek
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    Getting ready to do my brakes conversion. I hope it goes as smooth as all of yours did.
     
  4. Jun 19, 2016
    shaun

    shaun Member

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    Did any of you have to bore out your hub to match the disc brake. I had to go with a larger wheel stud because the rotor stud holes were bigger
     
  5. Jun 19, 2016
    45es

    45es Member

    Naches, WA
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    If I remember correctly, the ID of the rotor stud holes were the same diameter as the OD of the knurled portion of the wheel stud. This allowed the studs to pass thorough the rotor holes yet still keep them centered on the studs. Once the studs were pressed into the hub everything tighten up and the rotor stays true to the hub.
     
  6. Jun 20, 2016
    shaun

    shaun Member

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    For some reason my 77 cj rotorso have larger Dia. Stud hole.
     
  7. Jun 20, 2016
    Focker

    Focker Rust Never Sleeps Staff Member Sponsor

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    How much larger? Does the stud slop around or is there any resistance at all?
     
  8. Jun 20, 2016
    shaun

    shaun Member

    ohio, Beavercreek
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    Slops
     
  9. Jun 20, 2016
    Focker

    Focker Rust Never Sleeps Staff Member Sponsor

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    What is the make and part number of the rotors?
     
  10. Jun 20, 2016
    shaun

    shaun Member

    ohio, Beavercreek
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    77 cj. Part number BBR 3550RGS from O'Reilly

    Got it from you're earlier post.

    A lot of the part numbers are old since it was awhile ago since you made the thread.

    Is there a difference between 3550R and 3550RG. Both from a 77 jeep.
     
    Last edited by a moderator: Jun 20, 2016
  11. Jun 20, 2016
    Focker

    Focker Rust Never Sleeps Staff Member Sponsor

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    I'm not sure about the difference if any in the part numbers. The thread is only 8 months old so the part numbers should still be relevant.
     
  12. Jun 20, 2016
    shaun

    shaun Member

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    So you think boring out the original stud holes would be ok. Itsent only a small fraction. 671 of an in.
     
  13. Jun 20, 2016
    Focker

    Focker Rust Never Sleeps Staff Member Sponsor

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    I'm confused... I thought the rotor holes were too big? I wouldn't do anything to the hub holes. You want to press/drive the new studs in tight.
     
  14. Jun 20, 2016
    shaun

    shaun Member

    ohio, Beavercreek
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    The rotor holes are too big, had a lot of play with original wheel studs. Bought a larger shoulder width wheel stud and 1/4in longer. They will press tight with a tool assistance into the rotor but the hub holes are way too tight to press. Might bend or break hub.
     
  15. Jun 21, 2016
    45es

    45es Member

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    There's something wrong with those rotors. I would not be boring out the wheel stud hole in the hub. Go to RockAuto and order the rotors for half the cost. The part numbers the Focker posted are the correct ones. They are the numbers I use at the end of March 2 1/2 months ago.
     
  16. Jun 21, 2016
    shaun

    shaun Member

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    I'll try rock auto and return the ones to O'Reilly
     
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  17. Jun 25, 2016
    shaun

    shaun Member

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    Rock auto rotors are the same. Wheel stud falls into rotor with some play. May have to bore out hub a little.
     
  18. Jun 25, 2016
    Focker

    Focker Rust Never Sleeps Staff Member Sponsor

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    Resort back to the first set of Dorman studs. Assemble the rotor and the hub as I pictured. The Dorman studs should pass through the rotor and have to be pressed or gently hammered into the hub. Flip the rotor/hub over and suck the Dorman studs through using the lug nuts and an air gun.

    I can't remember how much "slop" there was with the Dorman studs and the rotor, but once they're secured through the hub, the rotor won't wiggle.
     
  19. Jun 25, 2016
    45es

    45es Member

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    ^^^ X2
     
  20. Aug 7, 2016
    Focker

    Focker Rust Never Sleeps Staff Member Sponsor

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    Update: Here's a quick tip to avoid the new outer pads (non piston side) from clanking in the caliper.

    Put the outer pad in a vise and bend the little tab/ear.
    [​IMG]

    Test a couple of times until you can't mount the pad flush in the caliper.
    [​IMG]

    Use a pair of channel locks and snap the top into place. If you can do it by hand it might not be tight enough.
    [​IMG]
     

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