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88-95 14bsf axle swap

I thought there were 2 different drum widths for the SF axle, which made the backing plates mount at different widths. It could be this was only for the 8-lug versions. I did find the old 14b s/f tech info thread, so anybody reading this should look there: https://ck5.com/forums/threads/14sf-tech-info.135125/
 
yea, definitely 2 different SF axle widths.
64-7/8" wms to wms
And the other one is around 67 if I recall.
 
Thanks for the great info everyone, excellent thread. I'm planning on piecing one of these together for my K10 this summer. Seems like the ideal solution to re-gear, keep my factory wheels and add some track width.
 
Can the 84-91 8-lug SF be sourced from both K20 and C20, or just K20? Is the C20 version any different? (or does the year range answer my question since K20 only went to 87?)
 
Yesterday I spend a productive day at my local Wrench-A-Part. I found backing plates and 33 1/8", 6-lug shafts in a mid 90's Express Van. Also scored a spare 3.73 r&p attached to a gov-loc in a mid 90's 2wd K2500. Don't overlook the Express Van's when looking for axle shafts. :-). $245 for shafts, backing plates, drums, gears and diff.

The 88-91 housing I have has 3.73's and an open diff. When the friend I got it from pulled the cover, there was an inch of gear oil goop in the bottom. Apparently the p.o. didn't think to ever change the oil. When I measured the backlash, it was big - .016" and looked pretty worn. The pinion gear had several thousands of end play, so the pinion bearings were worn slap-out. The pinion had no shims at all. The gear-set I pulled yesterday were factory, and were perfect, so I'm going to swap those over with the gov-loc, just going to have to set them up right. Guess I'll be buying a shim kit or maybe an install kit to get everything (nut, shims, bearings, seal, etc.), unless there's a benevolent CK5'er out there with a spare assortment of unused shims :whistle:. My plan is to pull the old 1310 yoke off one of my 10b's so I don't have to go with a x-over joint.

Went to my local Tractor supply to see if I could find 1/2" longer bolts to use once I get the 1/2" spacers for the backing plates. They didn't have the bolts I needed. Does anyone have the specs on what size/thread pitch those are? :dunno: I THINK they are 1.25 metric pitch, unsure of the metric diameter.
 
The R/V series would have been the same as the older C/K series.
Sorry I may have phrased that wrong - What I meant is can the axle be sourced from a 2WD as well as a 4WD? IE are they the same width? I know the OBS/GMT400 14-bolts were different between the 2wd and 4wd models.
 
Pretty sure the 14 sf 8 lug are all the same in width except for the van Sf 8
I'm quite sure that the 2wd SF 6 lug axles are too short for the 8 lug SF to 6 lug conversionI so that should give an idea.
I know there are ones one here that have researched it and know.
 
Pretty sure the 14 sf 8 lug are all the same in width except for the van Sf 8
I'm quite sure that the 2wd SF 6 lug axles are too short for the 8 lug SF to 6 lug conversionI so that should give an idea.
I know there are ones one here that have researched it and know.
Ok thanks that answers my question then!
 
So, looks like the bolts I'll need with 1/2" spacer are M12x1.25x40

OK so the M12x1.25x40 is the wrong diameter of bolt to attach the backing plates. It's a hair too small in diameter.

Anybody know the bolt size that holds the backing plates on???
 
Well, the 9.5" is sometimes referred to as metric, but it really isn't, except for some of the 90's wheel studs. So if 12mm is too small,1\2" is probably the answer.
 
Yeah looks like they're 1/2x20's, so I'll pick up some grade 8's 1/2" longer (1.5") on the way home tonight. Hoping do do some more work on the beast this weekend, and will try to get some good pics to share.
 
Sorry I may have phrased that wrong - What I meant is can the axle be sourced from a 2WD as well as a 4WD? IE are they the same width? I know the OBS/GMT400 14-bolts were different between the 2wd and 4wd models.
The shafts I measures at the boneyard out of a 90's 2wd 2500 were around 31"+ some change. The ones you need are 33.25". I've seen them in catalogs listed as 33.25, 33 3/8" etc, but the ones that are a tad over 33". Like I said - I found mine in a 90's Express van with a 14sf, and it was 6 lugs. What I mean is I got the axle shafts out of the Express Van. The housing wasn't right spring pad width. I'm using a housing out of 80's burb.
 
The axles out of an 88 + 4x4 are 33 1/8 I've got both here somewhere 2 and 4x4 out of early 90's. The 2x4 is 33 13/16.

Here's a reference

image.jpg
 
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