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swap 6-lug 14 bolt sf axle shafts into 8-lug sf--did a search

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 88K5Jimmy, Feb 5, 2003.

  1. 88K5Jimmy

    88K5Jimmy 1/2 ton status

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    I know somebody has done this just don't remember who. I am thinking of swapping 6-lug 14 bolt sf axle shafts into an 80's model 8-lug sf axle. Is this a direct swap or what has to be done in order to do this? I am thinking about doing this because I want to keep my 6-lug wheels and only plan on running 35's. Plus I drive very conservatively.

    What do you guys think?
    Thanks
    Ross
     
  2. sled_dog

    sled_dog 1 ton status

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    you're talking backwards somewhere here. You want to keep your 6 lug rims so I am guessing you want to swap from 8 lug SF to 6 lug SF not the other way around like you said.
     
  3. 90K5

    90K5 1/2 ton status

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    You can do this, but the widths will be a little different. A van 14 bolt is aobut 4 inches wider than the truck one, but i think can be had with 6 lug shafts. No matter what you do, you will have to do some swapping. The later model axles are not the same length and the earlier ones, so swapping to later model 6 lug shafts may not work, since oyu will have to change the drums, etc. I tihnk the best thing to do is get a later model on and move the perches and shock mounts
     
  4. TONYP

    TONYP 1/2 ton status

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    take a look at this kit, you have to do some work on your hubs but it allows you to keep your rims..

    8 to 6 lug
     
  5. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    Yes, I have done this swap. I'll give you all the info I aquired during the swap. So get comfortable.[​IMG]

    I got an 8 lug Semi-Floating axle from a 1986 3/4 Diesel suburban.
    I then purchased two 6 lug axleshafts from a Junkyard I found on the web. These shafts are from a 1992-99 1/2 4wd pickup with the 14B SF. Its a heavy duty towing package option. The other option is from a light duty 3/4 ton 2wd or 4wd pickup with said axle. Make sure the shafts are the 6 lug version.
    Next I had to change the brakes. The 13" drums were the only ones available for our year trucks on this axle. You need 11" drums because they were the only ones that came in a 6 lug version. With that you will need the required backing plates and all hardware, brake shoes, etc. <font color="blue"> I had a great GM parts guy look up every last little piece and part for this to make the brakes work correctly. I have all the PN's if needed. </font color>

    Next after putting all the brakes and hardware on for that, I slipped in the axleshafts. They were exactly 1/2 too long. /forums/images/graemlins/angryfire.gif I was so close and had this happen. With the axles being too long it pushed the drum out too far, not making the brakes work properly. I also checked the bearing surface on the axleshaft itself. It appeared to be long enough, actually turned/polished farther than the 8 lugger it was replacing. I decided to space out the backing plates by 1/2" on each side. I had to get longer bolts to do so, but I got some grade 8's from the hardware store. I used a locking nut (the kind with the washer with the serrations on it) to space out the backing plates. It turned out to be exactly 1/2" thick.
    Everything lined right up after that. Had no problems with bearings or seals. It actually makes the track width much closer to even with the front now. I get comments on why mine is like that from other Balzer guys around here. I try to explain it to them, but they are like "oh". DUH!!

    I ended up spending close to $500 by the time it was all said and done, but I think it is well worth it for my useage. I needed heavy duty, but not too much weight. The 14B SF has 33 spline axles and is much much beefier than a 10/12 bolt. It also weighs about 250lbs less than a 14FF.

    You will also need a conversion U-joint. Its NAPA part # 348 or 447. They are different, so get both and then take one back.

    I have put about 5000 miles of carefree use on this axle with no problems.

    I hope all this helps,
    John
     
  6. 88K5Jimmy

    88K5Jimmy 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    I hope all this helps

    [/ QUOTE ]

    You don't know how much that helps. Thanks a lot. I have a question though. If you were to convert the rear to disk brakes, would you just space the mounting bracket out a 1/2" on both sides for the brake calipers to grab the rotors?

    Thanks again
    Ross
     
  7. R72K5

    R72K5 Banned

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    how did you go about making/aquiring tube flange plate spacers ?
     
  8. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    Having not seen the way the mounting goes on a disc setup, I would still guess Yes you would. Because the axleshaft is still 1/2" too long. I think it would be fine with the spacer. But when you get it on, you need to make that call. Mine works fine, I would tend to believe yours would too.

    John
     
  9. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    I did not space out the flange or the tube. All I did was space out the backing plate 1/2". I used some nuts if the exact size of the bolt that holds on the backing plate to the flange. The 6lug axleshaft had enough machined/polished area to be 1/2" too long in this case. It was longer than the 8 lug in that area. The axletubes did not change, just the backing plates. I know its a little hard to explain. /forums/images/graemlins/smile.gif

    John
     
  10. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    Here's a pic I found of it. After this photo was taken, I also installed locking nuts on the back side of the axletube flange.
    [​IMG]

    John
     
  11. 88K5Jimmy

    88K5Jimmy 1/2 ton status

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    Now I understand what you did. Thanks so much for the pic! /forums/images/graemlins/thumb.gif

    Ross
     
  12. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    No problem.[​IMG][​IMG]
     
  13. 90K5

    90K5 1/2 ton status

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    If you have access to a machine shop or tools you could also make a spacer for the backing plates
     
  14. 88K5Jimmy

    88K5Jimmy 1/2 ton status

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    Is there any way drum brakes from a 10-bolt rear would work with this swap?
     
  15. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    I tried, believe me. The hole in the center of the backing plate was too small. And the bolt holes were off that hold the backing plate on. It just wouldnt work.

    John
     
  16. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    Yes, but access to those kinds of tools were not available to me. /forums/images/graemlins/frown.gif One day I may get a spacer made, but it works just fine for now. /forums/images/graemlins/thumb.gif

    John
     
  17. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    I tried, believe me. The hole in the center of the backing plate was too small. And the bolt holes were off that hold the backing plate on. It just wouldnt work.

    John

    [/ QUOTE ]

    I hate to disagree with you, but it will work. You have to get REAL creative with a 1/2" drill bit, but it'll work. I was told by the dealership that the backing plates for 11" rear brakes were discontinued...so I made my own. I'm not real proud of them, but they work.
     

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