10 Bolt to 14 Bolt

Discussion in 'Axles + Brakes' started by Ted Burkholder, May 14, 2019.

  1. Ted Burkholder

    Ted Burkholder Newbie

    Messages:
    3
    Likes Received:
    0
    Joined:
    May 13, 2019
    Location:
    Pittsburgh
    I was wondering if there was anyone willing to take the time to explain some things in greater detail. I saw a couple threads and gained a bit of knowledge on the issue but still had a few questions.

    I have a 98 K1500 with the 3.42 10 bolt. I found a local guy with a 14 bolt 3.42. Was wondering if I should bother with the switch? He said it came out of a 97 K1500. So is that a heavy half? Would there be any conversion to bolt that in?

    Another thing, I'll look up the difference between full float and semi float because I have no idea what that means. But which one is better? The 9.5" is a semi and the full is a 10.5" correct?

    I saw other people talking about the differences in the driveshaft, & the spring u bolt brackets too. From what I gathered, if I switched out the yoke and used the different u bolt brackets, the 14 bolt should fit right in? I can say that my truck currently has the alum driveshaft. But when I pickup a rear end, I can take the u bolt brackets & driveshaft also if I need them.

    I apologize if I am talking about a simple conversion that's been brought up a million times, but I'm new here...haha
     
  2. randomguy

    randomguy OBS Enthusiast

    Messages:
    87
    Likes Received:
    25
    Joined:
    Feb 25, 2018
    Location:
    Oregon
    The 14BFF is definitely the stronger and highest weight rated of the two, however it only came in 8 lug.

    The 9.5 14B semi float is a good axle and being 6 lug it makes life simpler. I assume a conversion u joint is available for your driveshaft. I’d snag the spring plates and e brake brackets and cable just to be safe. Personally, I would also use new u joints.

    When I was young and dumb I had a Suburban with the 9.5 14B on the 35’s. The truck had the Govloc and I beat the hell out of it without issues.
     
  3. alpinecrick

    alpinecrick OBS Enthusiast

    Messages:
    85
    Likes Received:
    17
    Joined:
    Jun 12, 2015
    Location:
    Western Slope of Colorado
    The "heavy half" was actually called C/K2500 Light Duty. It was a 1500 with the 2500 rear end. In addition to the 6 lug, 14 bolt semi floater axle/diff, it had it's own spring rate (4/1 leaf), the 3/4 ton rear drum brakes (11" drums?) and a heavier aluminum driveshaft rather than the composite driveshaft.
    Everything should bolt up except for the driveshaft. The 1500 driveshaft would most likely have to be shortened with a different knuckle on the diff end.
     
  4. Ted Burkholder

    Ted Burkholder Newbie

    Messages:
    3
    Likes Received:
    0
    Joined:
    May 13, 2019
    Location:
    Pittsburgh
    So if I took that driveshaft too, everything should work?
     
  5. shovelbill

    shovelbill I'm Awesome

    Messages:
    1,943
    Likes Received:
    1,434
    Joined:
    Feb 15, 2016
    Location:
    Upstate NY via Zoo Yawk Shitty
    well......a few years back, just after I got my '98 Sierra short bed, this swap was high on my priority list. Priorities changed and fell off my radar.

    My main reason was for better braking. You pretty much have the swap components covered. Being you, Ted, have a '98, I'll assume you have 4 w anti-lock brakes? If so an integral component will be the comp valve for the braking system.

    That valve I learned about from a thread somewhere. I'll try to find for you......It will turn your system from a JB5 to the heavier GVW JB6 system that the F44 coded half tons had......It won't change your LEGAL tow rating, as that is derived from your VIN, but it sure will give you a better braking truck, with lots more strength.
     
  6. Ted Burkholder

    Ted Burkholder Newbie

    Messages:
    3
    Likes Received:
    0
    Joined:
    May 13, 2019
    Location:
    Pittsburgh
    I do have AntiLock, yes. The comp valve?

    Good thing I asked because I have no idea what the hell that is...haha.

    I actually feel like a complete idiot asking these questions because I've been wrenching for 20 years. Just never done anything with these 4WD trucks or rear ends before.

    Also, (another dumb question) I thought all axles in 4wd drive trucks were posi? Is that not the case? Because the rear end I found, the guy said it's non-posi
     
  7. shovelbill

    shovelbill I'm Awesome

    Messages:
    1,943
    Likes Received:
    1,434
    Joined:
    Feb 15, 2016
    Location:
    Upstate NY via Zoo Yawk Shitty

    Do not feel like an idiot.....learning is an opportunity. Take it from an old fukker that learns something new every day.

    There is great information in this thread if you haven't read it yet: https://www.gmt400.com/threads/1500-heavy-half-14-bolt-qs.40589/

    To my knowledge, GM never put a "posi" in any of these trucks; they did use the Eaton Gov-lock, the G80 RPO coded limited slip unit.

    The combination valve, often referred to, incorrectly, as the proportioning valve, is necessary for a proper braking system. I forgot all the correct info about and I'm trying to find the saved threads that were my guide........I have to run out the door now, but I'll be back a bit later.
     
    Last edited: May 15, 2019
  8. evilunclegrimace

    evilunclegrimace I'm Awesome

    Messages:
    451
    Likes Received:
    139
    Joined:
    Sep 18, 2017
    Location:
    pennsylvaina
    [​IMG]
     
  9. shovelbill

    shovelbill I'm Awesome

    Messages:
    1,943
    Likes Received:
    1,434
    Joined:
    Feb 15, 2016
    Location:
    Upstate NY via Zoo Yawk Shitty
  10. slowburb

    slowburb all motor

    Messages:
    1,598
    Likes Received:
    594
    Joined:
    Mar 26, 2011
    Location:
    Louisiana
    3/4 ton 6 lug 14B was direct connection with conversion u-joint into my half ton suburban dirveshaft. No shortening required. Remember you'll only see a braking upgrade if your truck is not already equipped with the JB6 brakes. I swapped because I didn't want my engine/converter/transmission combination to eat any more rear ends; they made mincemeat out of the 10 bolt.
     

Share This Page