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Brakes

Discussion in 'The Garage' started by orangeGMC, Apr 26, 2005.

  1. orangeGMC

    orangeGMC 1/2 ton status

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    How do I know if I have JB6 or JB7 brakes on my 78 K25 pickup? I have to replace my master cylinder and the Autozone guy doesn't know the difference. Also which would I use when I do my rear disc swap? Does anybody have some part numbers I could cross reference?
     
  2. orangeGMC

    orangeGMC 1/2 ton status

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    Can anybody help me or give me a link to an old thread or something?
     
  3. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    Is the code on the glovebox door or similar? Sounds like a RPO code.

    John
     
  4. 77crewcab

    77crewcab 1/2 ton status

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    I had the same problem with mine. Check the size of the rear drum 13inch is JB7. As for the disc swap I dont have a clue.
     
  5. orangeGMC

    orangeGMC 1/2 ton status

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    I don't have anything on my glovebox. Iam not even sure it is the original one.
     
  6. shane74

    shane74 1/2 ton status

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    You can find the code on a sticker on the glove box door.

    For a new MC, use the JB7 code.

    If you have anymore ?'s about a disc swap, feel free to pm me.
     
  7. divorced

    divorced 3/4 ton status

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    I couldn't find any codes in my glove box either. I brought the truck and vin number to the local Chevy stealership and they couldn't even tell me which it was. The parts store ordered both for me to compare and they looked identical with the exception of different color paint markings. I bought the JB7 master cylinder and it works fine with my rear discs.
     

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