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Brakes. JB5, JB6/JD6, JB7/JD7, JB8...

This is a discussion on Brakes. JB5, JB6/JD6, JB7/JD7, JB8... within the Performance forums, part of the General Discussion category; For the uninitiated: JB5= 6400lb. disc 11.86X1.29 / drum 11.15X2.75 Vacuum-Double Diaphragm JB6= 7200lb (K20 and others) JB7= 8400lb. disc ...

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    Brakes. JB5, JB6/JD6, JB7/JD7, JB8...


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    For the uninitiated:
    JB5= 6400lb. disc 11.86X1.29 / drum 11.15X2.75 Vacuum-Double Diaphragm
    JB6= 7200lb (K20 and others)
    JB7= 8400lb. disc 12.50X1.54 / drum 13.00X2.50 Vacuum-Double Diaphragm
    JB8= 10000lb. disc 12.50X1.54 / drum 13.00X3.50 Hydraulic-Hydro-Boost

    JD6 & JD7, and JB8 (1-ton) are hydro-boost versions, so power assist comse from P/S hydraulics instead of vacuum hose.

    Here's a guy who upgraded his jeep: Hydroboost Brake Conversion. There are other threads around, too. Mostly jeeps.

    I'm looking at maybe needing a new power booster on my burban (JB5), so might as well consider upgrades, right?


    Would I need a different proportioning valve setup? Will I have problems locking up rear tires if I go to the larger brake system without changing axles/rotors/drums/etc?

  2. #2
    Need to be bigger!!!!!!! speedjunkie's Avatar
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    Re: Brakes. JB5, JB6/JD6, JB7/JD7, JB8...

    I upgraded to the Jb7 MC and 2500 calipers. alot better braking.
    Damian

    2011 GMC CC 4x4 6.2 black
    1998 Chevy ECSB 4x4 black full Throttle on 38s, traded.

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    Re: Brakes. JB5, JB6/JD6, JB7/JD7, JB8...

    cool. The jb7 reman vacuum booster is like $25 cheaper than jb5 for some reason at advance. I need new calipers, anyway (corroded bores).

    On rockauto, looks like the two caliper sizes take the same pads and bolt up the same?

    Hydroboost tickles my fancy except for changing out the P/S pump (PITA)

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    Registered User willis82's Avatar
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    Re: Brakes. JB5, JB6/JD6, JB7/JD7, JB8...

    you dont have to change the P/S pump to run hydroboost, just tee the return hose with a brass T and hose clamps. Been running it that way for years as well as a few others here with no problems.
    94 Chevy K1500 RCSB, 7in lift, SFA D44 HP front, NV3500, NP241 w/SS SYE, Hydroboost, vortec 350 w GMPP TBI vortec intake (soon to be vortec marine intake w/0411 PCM)

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    Need to be bigger!!!!!!! speedjunkie's Avatar
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    Re: Brakes. JB5, JB6/JD6, JB7/JD7, JB8...

    I used the 1/2 ton pads with the 3/4 caliper due to some rubbing. Works great.
    Damian

    2011 GMC CC 4x4 6.2 black
    1998 Chevy ECSB 4x4 black full Throttle on 38s, traded.

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    Re: Brakes. JB5, JB6/JD6, JB7/JD7, JB8...

    you dont have to change the P/S pump to run hydroboost, just tee the return hose with a brass T and hose clamps. Been running it that way for years as well as a few others here with no problems.
    Edit: Nevermind, I didn't realize the hydroboost units have 2 outlets!
    Your pump must have 2 outlets if all you needed was a return T... mine doesn't, so I'm not sure if I want to gamble with putting a T on the outlet without a high flow pump (I would use 10,000psi hydraulic hose with #6-jic fittings. The proper 18mmO-ring -> #6 fitting is $11 from summitracing,

    I paid for a jb7 caliper/booster/master setup from advance, but I haven't picked it up yet. $140.

    Looks like the hydroboost I'd want is Cardone P/N 527328 $160(oreilly), Or $50 from nearby junkyard, plus new master+calipers. =).
    Last edited by helo; 12-07-2010 at 10:15 AM.

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    Re: Brakes. JB5, JB6/JD6, JB7/JD7, JB8...

    Quote Originally Posted by speedjunkie View Post
    I used the 1/2 ton pads with the 3/4 caliper due to some rubbing. Works great.
    rubbing explain..want todo the swap..
    1999 Chevrolet Tahoe 4x4
    HT383e with Casper TEC, Granatelli Mass Air Sensor, AIRAID Intake Systems, PowerAid Throttle Body Spacer,JBA Headers, Magnaflow Cat back Exhaust,downpipes, and high flow cats.

 

 

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