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Will my 12 bolt work for me, or should I go 14BFF??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by CamaroZ85, Apr 1, 2003.

  1. CamaroZ85

    CamaroZ85 Registered Member

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    My Blazer currently has the 10b/12b out of a 78. It's lifted w/ 35's and I plan to keep it that way. I believe it has 4.10's in it now, but if not I'll eventually put them in. I live in NJ, we have mud and sand but no rocks. It will see some offroad time, but it will primarily be an on-road vehicle (though not DD, it may make some trips and will see bad weather). I'm looking to build up my drivetrain. If I keep the 12b, I plan to get a posi, new axles, c-clip elim and gears and new bearings all around. Will this hold up to decent offroad abuse as well as some heavy pedal on the street? I also dont want to deal w/ the issue of trying to install new rears on my truck just for the hassles of fitment and parts hunting etc. Plus, I just ordered 6 lug rims tonight. I also came across a good deal on a 14bff. So, I'd have to get new rims again, plus figure out the front. I guess I'd upgrade to 8 lug hubs/rotors (if possible) for my 10 bolt until I installed a D60 (if ever...). The install aside, I'd still have to get a posi for the 14b and re-do all the bearings. Then I'd have to figure out brakes, and would I need to upgrade the axles? My point is, either way I will have to invest some $$. Will putting $$ into the working 12 bolt be wise? With my upgrades, what would the 12b hold up to? Is the hassle worth it for the 14b?? I know I'm asking a ton of questions (no pun intended /forums/images/graemlins/tongue.gif) but I would love for someone to help me out. I basically went over my plans for how I'll be using the truck, and I know I want peace of mind as far as rears go, whats the best way to get me there?? Thanks for any and all input!!!
     
  2. Silver84k5

    Silver84k5 1/2 ton status

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    i would say yes, C-clip eliminator is a good idea, so if you do break an axle you dont lose your tire, 4;10's are still a fairly shallow gear so your pinion will still be strong enough to hold up, How much power is your motor pushin? i wouldnt get too hard on the skinny pedal as in, i wouldnt be doing any power braking on the street, but in the mud i think itll stand up to the task. and also a little peelin out on the street shouldnt hurt /forums/images/graemlins/thumb.gif
     
  3. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> If you're never going to go bigger than 35s then you'll probably be OK. You should know that the c-clip eliminators are not meant to be used off road, they are intended for drag racing and therefore are not designed to take side loading that happens off road. </font>
     
  4. CamaroZ85

    CamaroZ85 Registered Member

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    Thanks for the heads up on the c-clip elim. Is there any other way to get around that?? BTW the motor is stock for now (305 I think) I do plan to put a mild 350 in at some point (300 hp would suprise me from it) and I wont be burning out at all w/ the price of 35's /forums/images/graemlins/eek.gif As a side note, I did some rough pricing for both axles. The 12b is $1370 and the 14bff is $1079 (minus labor for setting up the gears) The only catch is I still have to pay to ship the 14b 3/4 of the way across the country! BTW this is Eaton posi, new bearings and Richmond 4.11's for both. The 12b also adds elim kit and axles, FWIW
     
  5. Panther212

    Panther212 Registered Member

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    It's always nice to have something like a 14 FF in rear, that way you always know that if something up front breaks, you can usually drive it home...

    14 FF's are cheap too.... I've heard 200 is the avg price... at the j-yards. that way with a detroit and 4.11s you're lookin at like $800 for a bulletproof axle
     
  6. Silver84k5

    Silver84k5 1/2 ton status

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    i personally wouldnt put that kinda money into either of those axles, i lucked out and got my 14 bolt for free, but when i had 5;13's a detroit, and new carrier bearings put in it i pair 800 bucks. that was parts and labor.
     
  7. Paxx

    Paxx 1/2 ton status

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    definitly go 14bff. If your talking about dumping over 1k into them y wouldn't you put the cash into the 1 ton. It's going to be way more reliable and cost a similar amount. Plus you only have to install it once and its done, so I say its worth the hassle of the install. /forums/images/graemlins/thumb.gif
     
  8. blazinzuk

    blazinzuk Buzzbox voodoo Premium Member GMOTM Winner

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    As has been said on other posts run your 1/2 ton stuff till it breaks and in the meantime look for a 14 bolt FF in your area they usually are not hard to find. Also you might want to find similar trucks to yours that have a locker in the rear and see if you can stand that I have replaced 5 limited slip diffs for freinds not because they broke but because they saw where a rig locked in the rear could go. That would also bring the price of the 14 BFF down a bit lockers are cheap for them. I have run with 35s and the 1/2 ton stuff with no problems for a while now so you should be fine with it in the meantime start looking for a 3/4 or 1 ton pickup for cheap (usually cheaper to get a 60 in the truck than out!) /forums/images/graemlins/rotfl.gif
     
  9. CamaroZ85

    CamaroZ85 Registered Member

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    Will I have any negative effects running a locker on the street? I dont want to be tearing up my tires doing that, I'd rather be tearing them up on some trails /forums/images/graemlins/grin.gif But seriously, I dont want to deal with any negative side effects from a locker if they are going to be too bad.
     
  10. Z3PR

    Z3PR Banned

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    [ QUOTE ]
    Plus, I just ordered 6 lug rims tonight.

    [/ QUOTE ] If you do decide to go with a 14 Bolt FF for the rear, you can get wheel adaptors so you can stay with your 6 lug rims. Just try to get a rear with matching gears for the front. Regearing isn't the cheapest thing to do. I bought a pair of axles with matching gears so I wouldn't have to deal with that problem. /forums/images/graemlins/grin.gif
     
  11. One_Ton_k5

    One_Ton_k5 1/2 ton status

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    Look on ebay, there is a guy in New Jersey selling 14 bolts all the time.

    I'll see if I can find a link for you.....
     
  12. One_Ton_k5

    One_Ton_k5 1/2 ton status

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  13. Silver84k5

    Silver84k5 1/2 ton status

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    [ QUOTE ]
    Will I have any negative effects running a locker on the street? I dont want to be tearing up my tires doing that, I'd rather be tearing them up on some trails /forums/images/graemlins/grin.gif But seriously, I dont want to deal with any negative side effects from a locker if they are going to be too bad.

    [/ QUOTE ]

    there are negative effects from running a locker on the street but IMO the pros far outweigh the cons, when it comes to this, i dunno bout "tearin up" trails, delibratley (somtimes it happens but dont make a point of doing it) but anyway , you will be able "Tear up" alot more with a locker in there. In a rig that is going to be built for offroad use, a locker is a must, atleast in the rear.
     
  14. Tweetysuarus

    Tweetysuarus 1/2 ton status

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    I've been running D44 &amp; 12 bolt for two years now with 38.5's and 4:56 &amp; detroits! Works well so far no problems yet! /forums/images/graemlins/thumb.gif
    Bill
     
  15. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    As has been said on other posts run your 1/2 ton stuff till it breaks and in the meantime look for a 14 bolt FF in your area they usually are not hard to find. Also you might want to find similar trucks to yours that have a locker in the rear and see if you can stand that I have replaced 5 limited slip diffs for freinds not because they broke but because they saw where a rig locked in the rear could go. That would also bring the price of the 14 BFF down a bit lockers are cheap for them. I have run with 35s and the 1/2 ton stuff with no problems for a while now so you should be fine with it in the meantime start looking for a 3/4 or 1 ton pickup for cheap (usually cheaper to get a 60 in the truck than out!) /forums/images/graemlins/rotfl.gif

    [/ QUOTE ]

    All you guys are missing one point here.
    He said he is sticking with 35" tires, so if he goes 14bFF he looses about 2" in ground clearance, with a 35" tires that is a lot.
    I have 12 bolt with 35" and i wish I had more clearance so I got som 38" tires, and I will baby it to make them work.
    Plus if he sticks with a posi, it's not easy to break them.
    I have had lockers on my 1/2 ton axles with the 35" for 2 years, no problem, and that is with a big torquey diesel and a manual tranny.
    An auto will be even gentler on axles, something a lot of people seem to overlook.
     
  16. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    Unless you are building this to tow something keep the 12B. If realy want a FF use a D60 out of a "D" or "F", the FF14B takes away too much ground clearance w/ 35s. If you do a swap to rear discs your wheel will be retained better than w/ drums if you snap a shaft.
     
  17. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Here's my feeling on keeping the 12 bolt.
    http://coloradok5.com/ctm-d44.shtml
    Yeah the locker is more expensive but unless you get a smoking deal on a D60 for the front your going to shell out $3k or better to go D60/14. Like was pointed out the 14 is going to be a boat anchor on 35's. to get the same clearence at the diff with a 14 that you have now withthe 12 your going to have to run 38-39's.
     
  18. CamaroZ85

    CamaroZ85 Registered Member

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    So grim what do you have in your 12 bolt? How do you abuse it and how does it hold up?
     
  19. blazinzuk

    blazinzuk Buzzbox voodoo Premium Member GMOTM Winner

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    If clearance is a huge issue and if you know someone who has a welder and a grinder shave the 14 bolt I am in the process of shaving mine and will gain almost an inch of clearance on it. There is alot to be said for haveing the peace of mind of a 14 bolt FF but everyone is right the 12 bolt will probably be fine. Also I e-mailed Moser a couple of times they have new shafts for 12 bolts that are supposedly way strong. /forums/images/graemlins/rotfl.gif
     
  20. CamaroZ85

    CamaroZ85 Registered Member

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    yeah I emailed moser as well, they told me about c-clip elimination. I cant use the regular setup that you would on a car for drag racing, but they said they have axle ends you have to cut off and weld on which accept the ford type press on bearings, maybe I'll look into that...
     

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