4 to 4.5 bolt pattern front discs

Brakes for your Classic Mopar

  1. Jason Holt

    Jason Holt Member

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    I have a 1967 Dodge Dart gt convertible. The previous owner made the front disc brake conversion. What does it entail to change from small bolt pattern (4'') to(4.5") bolt pattern? Can I just change rotors?
     
  2. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    You have 5x4" Kelsey Hayes disks?

    Or one of those conversion kits from Pirate Jack that has the rotors drilled for 5x4" but is actually a 73+ disk set up?

    Or something else entirely?

    If you have the KH disks there's a way to use a Kelsey Hayes Mustang rotor to get the 5x4.5" pattern on your current spindles, calipers etc. but there's machining involved. Using mustang rotors for 4.5" bc Otherwise a swap or conversion will include a lot more than just rotors.

    If you have a Pirate Jack kit then you already have the 73+ disks spindles, calipers and brackets and you can just buy the standard 73+ rotors.

    If you've got some homemade madness, it will depend on what you have for spindles and upper control arms, but more than likely it'll take more than just rotors.
     
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    • Lord Sparky

      Lord Sparky Well-Known Member

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      Don’t forget the back axels.
       
    • dano

      dano Evil Handy Man

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      With a lot of these brake swaps you have to start to watch wheel offset, they typically start to need more positive offset to fit correctly. Lots of folks look to 94-up Mustang wheels or ones for their fitment.

      What do you have for a rear now?

      Overall, how are you going to drive the car and what do you expect? Cruiser, corner carver, stock looking driver, hot street car?
       
    • Professor Fate

      Professor Fate Push the button, Max...

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    • cudamark

      cudamark FABO Gold Member FABO Gold Member

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      What's wrong with the small bolt pattern brakes?
       
    • pntastar69

      pntastar69 Well-Known Member

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      I had my rotors redrilled from 4" to 4.5" by Moser Eng way back in 2002. They machined off the old studs, redrilled for 4.5" and installed threaded studs. Been on the car since, no issues. If you go this route, on most 15" wheels, the ID of the wheel (center hole) will be larger than the OD of the hub hence, it will now be lug concentric instead of hub concentric. Been running like this for years w/no issues. They do sell hub concentric ring adapters to fill the void on the hub to wheel. Don't know if Moser still to it.

      Dscn1087.jpg

      Dscn1086.jpg
       
    • pntastar69

      pntastar69 Well-Known Member

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      With threaded studs installed.

      Dscn1088.jpg
       
    • diymirage

      diymirage HP@idle > hondaHP@redline

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      gotta wonder why they didnt space the new studs evenly between the old ones, instead of cramming them in like that
       
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