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14SF "tech" info

Discussion in 'The Garage' started by dyeager535, Apr 11, 2005.

  1. dyeager535

    dyeager535 1 ton status Premium Member

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    Didn't ever really come across any posts with a compilation of 14SF tech info. I copied this out of the other post I made, since the old title isn't accurate anymore. This basically is everything I've learned thus far in my 10 bolt to 14SF swap. Hope this info will help people out in the future.

    Originally asked about wrench size needed for rear u-bolts, answer was same as 10, 12, and 14FF. 15/16".

    On that same note, are the axle tubes for the 14FF and SF the same diameter? Yes

    Rene: "Pretty sure the SF has 3.375" tubes like the FF does. I just opened up my 1/2 ton spring plate holes a little and made them work..."

    In my case, which SHOULD be the norm (have heard otherwise though) the u-bolts are therefore not interchangeable between 10/12 bolt axles and the 14SF/FF. Spring plate can be made to work, but IMO might as well get those when you get the u-bolts, at least if buying used like I did.

    Other info I came up with so far:

    The diff housing cover bolts are not interchangeable with the 10 bolts. Same threads, but the length is different. (5/16 if standard) FYI, it appears at some point GM went metric on these, so be warned! Check first...8mm x 1.25 was the metric size given.

    Pinion shaft retaining bolt is 10MM. (5/16" for 10/12 IIRC) Bearing cap bolts are metric too, can't recall the size. Internally everything looks identical to a 10/12 bolt, except bigger. Gov-lock is same design in 10/12 and 14SF applicaitions. 14SF gov-lock was broken when I bought this axle. Something had caused the teeth to strip off of one of the governor gears and the toothed ring they ride on, rendering the locker inoperable.

    At least later 14SF's wheel cylinder brake line fitting comes out parallel with the axle. The 10 (and 12?) bolts come out at around a 45* angle. Expect it, don't crossthread the fittings, if you can get them out in the first place. :(

    Napa pulled a wheel cylinder for 3/4 ton "small brake" K20 Suburban that was identical to a 10 bolt. That isn't right, at least not for the later 14SF's, and I doubt any 14SF's. The diameter is smaller than the 14SF, and the fitting angle is wrong. The one they pulled for same vehicle except 1997 was exactly what I had. Interestingly, the big brake and small brake option wheel cylinders are different part numbers for 1997 at Napa, yet they are the same externally in every way, even casting number, which indicates no difference. Who knows?

    All the "small" brake parts for the "small brake" 14SF and 10 bolt appear to be interchangeable. Same setup inside the housing with springs, pins, etc.

    Here are the pics:

    [​IMG]
    wheel cylinder 14SF left, 10 bolt right. Notice fitting angle, diameter difference. "Width" is the same, and bolt pattern/threads on back are the same for mounting, so the wheel cylinders *will* interchange, but would probably result in weak rear brakes.

    [​IMG]

    14SF orange drum, 10 bolt unpainted.

    [​IMG]

    14SF orange drum, 10 bolt unpainted. "Bulge" on the 14SF drum is approximately 1/2 of how much wider the 14SF is than a rear 10/12 bolt.

    [​IMG]

    10 bolt on left. 14MM studs on the 14SF, at least my year. That varies based on year/number of lugs I'm sure. Hub cutout much smaller on the later 14SF due to IFS wheels. The stock ralleys for the '73-87 trucks work, lug studs BARELY fit through wheel, but wheel is no longer hub centric of course. *Note*: The 14MM studs/lug nuts will fit with stock 6 lug wheels, HOWEVER the stock 14MM lug nuts will only pinch the wheel to the axle, they will NOT bite into the hole in the wheel as is "necessary" (IMO) for there to be a good tight fit. The holes in the wheel will need opened up or you will have to switch lug nuts front, rear, or both. I did not realize this until I tried to swap wheels to the front that had been on the rear. Once a wheel has been used with 14MM lugs/bolts, you can't use it on the stock 1/2 ton lugs.
    [​IMG]

    14SF on top

    Axle specs from splined end to bearing surface. (measurement taken at each seperate, distinct diameter)

    10B: 1.16", 1.31", 1.62" bearing surface.
    14SF: 1.42", 1.655:, 1.70" bearing surface.

    28 or 30 spline axles for 10 bolt, 28 spline for all 12 bolts too? 33 spline for all 14SF's.

    Anyone interested in more data/info I didn't provide but might be able to while this thing still isn't "buttoned up"?

    More info:
    http://coloradok5.com/forums/showthread.php?t=170383

    EDIT: Disk Brake info: http://coloradok5.com/forums/showthread.php?t=176462

    EDIT: Quote from u2slow "Both versions need the perches moved (same spacing 2wd and 4wd). The difference is the overall width. (talking '88+ C/K body style)

    RPO code "F44" gets you the 14bSF on a 88-98 K1500. Its standard issue on a 6-lug C/K2500." So on a half ton, you can ask an owner if the RPO tag has F44, that should equate to a 14SF rear axle. Not on a 3/4 ton as it is standard.

    EDIT: 14SF axle flange thickness is .451" The brake drum is .330" thick at the flange mating surface.

    EDIT: Conversion u-joints for 10B to 14SF: "Neapco 1-1153. Napa had one under p/n 447 but I think they changed the number awhile back" 10 bolt is the S44 joint, 14SF is 1350.

    2WD/4WD conversion, and axle seal numbers for the numerous seals the 14SF used http://coloradok5.com/forums/showthread.php?t=311473

    EDIT: Had a problem with the axle seals I installed 10 years ago lol. When I put them in they were not a press fit. I put them in with silicone. Well, the one failed, and ruined my brake shoes, which had plenty of life left. The generic part number most everyone uses is 710105. The "National" brand sold by Schucks (suck it O'Reilly's) is a press fit. The one that did not fit is marked "Timken" on the seal portion, along with the 710105. Maybe they fixed it in the past 10 years, but my calipers told me they have not. I didn't even bother trying, too long of a drive to test it out.

    Additionally, according to the computers, there are two axle (they call them wheel) seal diameters. One is 3.08", the other is 3.03". The 3.08" seals all appear to be flanged. The 3.03" seals are all depicted flangeless. The difference in size is appreciable when you have them back to back. It takes a good look, but you can see it. No idea where this 3.03" seal was supposedly used, the computer shoed the 710105 interchanging from 1982-1999. Perhaps the 3.03 was even later.
     
    Last edited: Mar 27, 2016
  2. HarryH3

    HarryH3 1 ton status Author

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    The axle bearings for the 14sf are also much beefier than the ones found in a 10 bolt. :)

    Also, when I asked at the driveshaft shop about a crossover u-joint to make my 1/2-ton driveshaft fit up to the 3/4-ton yoke, they suggested that I just swap the yokes instead. Much to my surprise, they are interchangeable! :eek1: I just moved the 10 bolt yoke to the 14sf.
     
  3. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    Very nice post!
     
  4. Triaged

    Triaged 1/2 ton status

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    Could you measure things like:
    distance from backing plate flange to axle flange
    Thickness of center pin
    Axle tube OD and thickness
    bore of wheel cylinders (might be marked on them)
    Depth of drums
    WMS-WMS
    Distance from axle centerline to yoke centerline
    Distance from axle centerline to lowest part of housing

    Thanks!
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, this ones not torn down, I just don't have fluid in it or a gasket on it, so it's easy to pull some stuff apart. I'll take a look next time I'm with the truck again and see if I can't figure out a way to measure some of this stuff though.

    Easy, I'll get that one.

    Rene got part of this one, 3.375". Thickness not sure how I'd measure that with seals and carrier in place.

    Didn't see it marked, but I've got the old ones, I can pull one apart easily enough.

    I'd be willing to bet almost exactly 1.5" deeper than the 10 bolt drums, but I'll measure to get exacts.

    Can do, but that won't help find others like it, since I don't know the origin of this axle. Again, I'm betting WMS to WMS is 3" more than 10/12 bolt. My front/rear tires are now even.

    Axle centerline to lowest part of housing is easy, but what do you mean axle centerline to yoke centerline? As in, install u-joint, measure from axle centerline to center of u-joint cap to figure out how much shorter or longer a driveshaft would need to be compared with other axles?

    It will be Friday before I can get started on this, and even then only if no rain!
     
  6. Triaged

    Triaged 1/2 ton status

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    Well obviously it was a 4x4 (from the 6-lug). My guess is a 88-?? IFS truck with 'heavy-half' (highest optional GVWR for 1/2-ton) type suspension.

    That is it exactly. That way people that want to swap will know if the driveshaft needs to be shortened. 10-bolts are around 12". Would also be interisting to see if the yokes themselves are different length.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    IIRC even 3/4 tons some years were 14SF with 6 lug. Are you discerning application weight based on something other than 6 lug? I was *told* this was something like a 1997 Yukon axle, then again I was told this worked perfectly when I bought it. :crazy:

    It definitely is newer, the perches and shock mounts had all been butchered to make it fit the older truck.
     
  8. zcarczar

    zcarczar 1/2 ton status

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    Yes, the Driveshafts need to be shortened. I went from 10 bolt to 14 bolt SF and had to shorten the shaft a bit.

    They also have a standard 1350 U joint yoke. I dont know if anyone makes a u-bolt style yoke for it yet though.
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Did you happen to get a specific measurement? Just curious, I'll still get an exact measurement as requested. I did a *rough* comparison of the 10 bolt to the 14SF with a tape measure and I came up with about a 1.5" difference. I wouldn't be surprised if the actual is right around 1".
     
  10. Emmettology 101

    Emmettology 101 3/4 ton status

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    You are correct. Some people refer to them as Heavy half tons and some 3/4 tons..... My 89 had 2500 badges on it and is a 14sf 6 lugger. But I have also seen 1500 labeled trucks with a 14sf 6 lugger also...
     
  11. marv_springer

    marv_springer 1/2 ton status

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    Weird facts/rumors about the 14bsf

    I've heard that the H2 14b is 30 spline?? :dunno:....

    Anyone confirm this..!? :confused:

    Marv
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    According to ARB's application chart, both front and rear of the H2 is 33 spline.
     
  13. Blue85

    Blue85 Troll Premium Member

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    In my case (*your results may vary*), swapping in the 14b s/f made my stock driveshaft about the right length again. After the 4" lift (actually 4.5" in the rear) the slip yoke was sticking out too far. Then with the axle swap it made it sit about right again. :)

    Of course in a K5, a shorter driveline is worse, all else being equal :frown1:, but without modifying the shaft, having too much slip yoke sticking out will only make vibration and wear worse (it's not really a longer driveshaft). Later I gained 4 real inches of real driveline length by going with a fixed yoke on the transfer case :grin:
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    Pinion shaft:
    1.925"

    1"

    5.25" vs. 4" on the 10 bolt.

    68"

    13.5"

    7"

    The last two are going to be a hair off, pretty hard to measure with the tools I have and only two hands.

    It was getting dark, but the difference between the 10 bolt and small brake 14SF brake pads is pretty minimal. The pad surface is about 2" longer on the 14SF than the 10 bolt, but width is exactly the same, and the actual brake backing piece looks to be the same as well. If you were cheap and didn't care about rear braking, you could probably swap them out.

    Sorry I couldn't get any more measurements, the axle is back together now.
     
  15. Triaged

    Triaged 1/2 ton status

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    [right-click/save as]

    Thanks :cool1:
     
  16. u2slow

    u2slow 1/2 ton status

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    You may want to point out that there's three widths of the 6-lug 14SF....

    C2500: ~64" wide
    K1500/2500: ~68" (your measurement)
    G2500 (Savana/Express) I assume its wider still...

    GM's driveshafts are between 1/4" to 3/8" shorter for the 14SF vs the same truck with a 10-bolt for the same year.
     
  17. Pow06er

    Pow06er 1/2 ton status

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    o i need some help b4 i tackle this I have a 14sf from a C2500 i believe

    can i make it work for my k5

    Will i have to shorten the shaft for a 4" lift and 35s?

    I dont want to waste $$$ rebuilding the 10 bolt

    Also wat is the best cheapest way to rebuilding the brakes? all i have is hubs

    according to measurements i need to move in 3" and shock tabs out 1"
     
  18. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    My SF14B used a 21mm. It came off an IFS truck w/ the inverted, straight top, u-bolts.
     
  19. dyeager535

    dyeager535 1 ton status Premium Member

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    They may have changed on the later ones then. The early ones (originally installed in our trucks) will all be 15/16.

    What year was your 14SF? Might be able to narrow it down a bit.
     
  20. Pow06er

    Pow06er 1/2 ton status

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    any luck on my previous ???s
     

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