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Caliper upgrade?

Discussion in 'Brakes' started by usar17, Jun 11, 2019.

  1. usar17

    usar17 Full Access Member

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    So I swapped in Hydroboost, converted dear 14bolt FF to disc with JB6 calipers, added a manual brake fluid proportioning valve in for the rear line, front axle is 8 lug gm 10 bolt with JB6 calipers.

    Can I just swap out the front Calipers and rubber hoses to JB7 for better braking? Or do the rotors need swapped? I currently am 1.25" thick by 12.5" diameter ACDelco #18A61A rotors all around.

    I assume leaving the rear JB6 is fine/recommended.

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    Last edited: Jun 11, 2019
  2. Blue Ox

    Blue Ox Turning Diesel Fuel Into Fun

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    8 lug rotors are the same between the JB6 and JB7. Different calipers, pads, different master and different drums/wheel cylinders but it looks like you've already changed that.
     
  3. usar17

    usar17 Full Access Member

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    would there be any reason why I should not upgrade the rear brakes on my 14 bolt full floater with disc brake conversion to the jb7 style calipers?

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  4. 4WDKC

    4WDKC Full Access Member

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    Yes, as you brake the weight of the vehicle transfers to the front tires, having equal braking pressure on the rear without weight on it will cause the rears to lock up and possibly spin you out. This is also why 3/4 and 1 tons had the brake valve (cant remember the actual name) that allowed more pressure to the massive brakes of the 14 bolt/ D70 rear axles when there was weight on it and reduced the pressure applied with no weight.

    Replace the master cylinder also.
     
  5. usar17

    usar17 Full Access Member

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    I know the valve you're referring to, I'm debating installing one but currently the manual valve is a huge help. I'm about to install the larger jb7s upfront. I'm just asking if I should throw jb7 in the rear or keep them Jb6. I don't haul a ton. And the main thing I tow is 6,000 of pontoon boat/trailer.

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  6. 4WDKC

    4WDKC Full Access Member

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    Most people scrap them when they start having problems, I would leave the JB6 on the rear and put the JB7 on the front.
     
  7. Craig 85

    Craig 85 Full Access Member

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    You have to adjust that valve to match your lift. I had a shop do a lift on my truck in 1990. They didn't lift the valve far enough. It caused me to lose brake pressure on the rear brakes and I almost ran though a red light towing my El Camino.
     
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  8. usar17

    usar17 Full Access Member

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    So all switched over. Bled the brakes and the pedal was nice and firm. Started the truck and now it goes to the floor easily and the brakes suck...

    Bled it again while the trucks running and still shitty :/ what did I screw up??

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  9. usar17

    usar17 Full Access Member

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    Disregard. 3rd bleed and now everything is perfect :)

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