Recent content by Gibson

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    97 k2500 suburban front and rear diff. gear issues

    I suppose you have the 454 engine? For a '97 K2500 their were only 2 ratios from the factory. The 350s were ONLY shipped with 4:10 ratios. The 454s came standard with 3:73 with 4:10 an option. Unless you're doing a lot of highway speed cruising the 4:10s give better all-around performance/response.
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    MC upgrade question

    I gotta say, about the 2 square bodies I had, that I was like the 3rd>4th owner, they had high milage, and who knows what the previous owners did. The '80 was from Canada. I never changed MCs on them, just assumed they were "stock" as I got them. So I easily could be wrong about them.
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    MC upgrade question

    I used wrong terminology too, my '97 Sub has JD7, not JB7, it does have hydroboost, sorry. I agree with you, using a MC made for 4 wheel discs on rigs with drums in the rear isn't so great. I "think" they only used low drags on the 1/2 tons, right?
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    MC upgrade question

    Sure, both of the old Square body rigs that I had, the '76 and '80, and my '97 Sub all had/have MCs that have 2 different dia. pistons in them. The big piston runs the rear drums and the small piston runs the front discs. The '76 and'80 had JB8, the Sub is JB7.
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    MC upgrade question

    Schurkey is right, the NBS masters are used on 4 wheel disc applications. But their is more to it, their are lots of "Step bore" MCs that are used with "Normal drag" disc/drum systems, and they do have a larger rear bore, and can appear to look just like a step bore MC that is used for "Low...
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    Squishy brakes won't go away!

    The first thing I would check is the adjustment of the rear brakes. Too much shoe-to-drum clearance= lots of pedal travel before brakes take hold. Remember, the front discs will do nothing until the rear shoes contact the drums.
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    Everyday/towing

    Yeah,, gotta agree with that. Having to start moving on an uphill grade with a heavy trailer is not healthy for clutches.
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    2500 to 3500 conversion?

    In the GMT 400 platform they did build a "light duty" 3500. It was 9,200 GVW. They were govt. rigs, most went to the Forest Service. The ones I've seen had FF 14 bolt rears, the 3500 A-arms/front end, and a 5 speed manual trans. Also, no power windows/seats, no carpeting, just rubber floor mats...
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    Calipers......

    Right,, much of the talk about "warped rotors" is really the rotors developing "hard spots", where their are alternating areas of the rotor which have different coefficients of friction. Having clean and easy sliding calipers/caliper pins cures much of what is incorrectly called warped rotors.
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    what Proportion valve to use

    Not so, ABS acts to dump pressure to a circuit that is locking up. If the brakes are not locking up the ABS does nothing, and it has nothing to do with any proportioning between front and rear brakes. This is the correct choice when changing the rear drums to discs. With discs you want full...
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    Brake Issue

    That's not a guaranty of a solid system, air can still be in the ABS module. Using a scan tool to cycle the ABS along with pressure bleeding is the best way to proceed.
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    JB5 JB6 JB7 JB8 Size Thread

    It's generally a trouble free system,, kinda like a light bulb, it either works,, or not. Assuming that their are no leaks or air in the system, the most common cause of poor Hydroboost performance is a power steering pump that's marginal.
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    Rear disc and hydro boost swap

    Welcome to the forum. You'll probably get better and more detailed responses if you tell us what model vehicle you're working on. 1, A 1/2 ton or a 3/4 ton,, or maybe a 1 ton? 2, What year is it?
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    Adjustable proportioning valve for ABS Delete

    When you got rid of the ABS, you eliminated any "proportioning" of pressure. The ABS modules have/had a "Combination Valve" mounted on them. Depending upon the brake system; JB5/JB6/JB7/JB, the combination valve had a pressure value built into it that had a factory pressure rating matched to the...
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    NBS master cylinder Swap

    I've sure looked under the hoods of a lot of Vortec trucks. And there it is, a combination valve bolted to the ABS unit.
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