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14 bolt rear with 6 bolt pattern

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Blazin Obsession, Oct 9, 2001.

  1. Blazin Obsession

    Blazin Obsession Registered Member

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    I want to get rid of my 10 bolt rear and install a 14 bolt, I noticed that a 89 3/4 ton pick up at work has a 14 bolt with a six bolt pattern, sounds perfect. But is it ??? I need some help understanding what 14 bolt FF and 14 bolt khsdgkhsg??? are and what this one in the 89 might be?
    thanks
    Ken
     
  2. Sparky87k5

    Sparky87k5 1/2 ton status

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    6 bolt 3/4 ton axles are 14 Bolt semi floaters. Much better axle than 10 bolt rear and a somewhat stronger than 12 bolt axles. Good choice if you want to stay 6 bolt wheels. BUT if you want the strongest approach, go with 14BFF! Bulletproof.

    A good firm grip is my idea of gun control!
     
  3. Sparky

    Sparky 1/2 ton status

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    14 bolt FF is a 1 or 3/4 ton axle and the ff stands for full floating. Its a superior design to to a 14 bolt sf in so far as there are no c-clips that when broken allow the axle shaft to come out. 10 bolt and 12 bolt axles are both c-clip axles as well. Correct me if I am wrong here, but I am pretty sure that the 14bolt sf is the only 14 bolt to come in a 6 lug pattern, and came on a select few years of 3/4 ton 2 wheel drive trucks. It is stronger than the half ton 12 and 10 bolts, but it leaves the full floating function to be desired. On the other hand, it is alot lighter than the 14bolt ff. You can look up additional axle information on CK5's technical information.

    Sparky

    When all else fails... Check the blinker fluid.
    78 K-5
     
  4. Blazin Obsession

    Blazin Obsession Registered Member

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    Great answers, thanks for the help
    Ken
     
  5. Blue85

    Blue85 Troll Premium Member

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    I am working on getting a 6-lug 14 Bolt right now, too. There aren't any that are direct bolt-in replacements in a K-5. You have a few choices:
    -get an 80's 3/4-ton 8 lug (found mostly under 3/4 subs) and have the bolt pattern changed. for about $30, you can ship the shafts and drums to Moser Engineering and they do the machining for about $80. Make sure that when you are done, the stub that sticks out of the end of the axle will fit through the opening in your 6-lug wheel. Also don't bother getting this done to crap drums.
    -Get a 6-lugger from an '88+ pickup truck. They are under some Z71's and other "light-duty 3/4 tons". They need the spring perches and shock mounts cut off and welded on in the correct position for the K-5's narrower frame rail spacing.
    -The hybrid option is to find the older housing and newer axle shafts and drums and put it all together for a bolt in. My understanding is that this works without even needing different bearings or seals. However, there are different lenghts of axleshafts to accomodate different size brakes, so make sure you know what you want and that it rides right in your housing.

    You will need an adapter U-joint or a 3/4 ton driveshaft no matter what you do.

    Another great option is to get an 8-lug 14BSF and order custom ("upgrade") axles with the 6-bolt pattern. Then go to the junkyard and get the backing plates, rotors, calipers, caliper bolts and flex hoses from the front of a 6-lug 4x4. Then redrill the mounting holes in the backing plates, make some spacers and viola - rear disc brakes (you may need a proportioning valve). This looks especially cheap when you see that replacement drums are $80-$100 each. You will have no parking brake, but with an automatic, that is OK most of the time. If you blow the rear driveshaft, just put it in 4 wheel drive before putting it in park.

    <font color=green>Does a Dyslexic Insomniac Athiest lay awake at night wondering if there's really a Dog?</font color=green>
     
  6. Blue85

    Blue85 Troll Premium Member

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    I don't think that the 14BSF is "somewhat stronger" than the 12 bolt. It is in fact "stronger".
    Axle Ring gear diameter
    10-bolt 8.5"
    12-bolt 8.75"?
    14SF 9.5"
    14FF 10.5"

    The other components in these axles are basically sized proportionately to the ring gear size. So the 14SF is a bigger step up in strength from the 12 bolt than the 12 bolt is from the 10 bolt. They are a 3/4 ton axle after all and were the rear end for the 454SS trucks (although those weren't particularly potent Rats...)

    The 14BSF is the king of the C-clip axles. Yes, if you break a shaft, you can lose the wheel, but how often does that happen with these axles? A lot less than with 10-bolts. And if you put on disc brakes, you can still drive back out of the woods. Plus, remember that a 14SF has as much ground clearance with 35's as a 14FF has with 36's. You will also save a lot of bones over the years if you run 15" wheels instead of something bigger.

    Just be honest with yourself as to how you're going to use the vehicle. If you're going to seriously abuse the truck, get the FF.

    <font color=green>Does a Dyslexic Insomniac Athiest lay awake at night wondering if there's really a Dog?</font color=green>
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Sparky, the 14 SF has come in all 3/4 tons since 1982. Some have got full floaters, but not many. The truck I got my SF from had a Diesel in it from the factory, then a big block, so my small block is a real change from the rest of the way it has lived its life.

    I 2nd that the 14 SF is a LOT stronger than a 12 bolt. The shafts on it are monsterous, it has 3 3/8" tubes, 33 spline shafts, etc. Mine is 8 lug.

    There are no disc brake conversion kits for 8 lug 14 SF's, but they are available for the 6 lug version.

    I love my 14 bolt SF. It has a posi unit, 4.10 gears, and is so far indestructable (I destroyed both a 10 bolt and a 12 bolt before getting this one). Best of all was the total cost for it: NOTHING.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     

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