88-95 14bsf axle swap

[blazer74]

I have both 6 lug versions 2 and 4x4, I'm leaning towards the 2x4 version, it's a touch wider than the 12 bolt I have now.
Basically 3 inches diff between the 2 and 4x4 versions. 65 and 68 inches rounding up.

Also depends on you rim back spacing you have how the tires stick out
The wider also increases your turn radius some. Matter of preference.

 

[Irish1941]

I did use a 4x4 rear end because of the added width.

Personally I don't know why you'd want to convert an older 8 lug 14bsf to 6 lug

Like Jeff, I did it to keep my 6 lug pattern & 3 sets of steelie/Aloca rims and avoid the cost & time searching for right geared '88-'98 9.5.
You do know they are the exact same axle right?
Nothing changed. Same carrier, same 33 spline etc...
'91 14SF 6 lug is nearly the exactly same as '91 14SF 8 lug except for brakes and axle length.
That's why Jeff was able to drop a factory e-locker in from a 2000 something H2 his '90 Sub axle. Same same...Plus there are FAR more '84-91 8 lugs out there than later 6 lug versions.
A lot places here think the 4x4 6 lug 14sf is gold. I can get both '89-'91 Sub 3/4 axles for $200 with 4.10s. A 6 lug 9.5 rear from 4WD is $400-$500 and most are 3.54 or 3.73. That means re-gearing. More $$$
You gotta go thru a used rear end anyways so why not go the cheap route? Added bonus : no perches or shock mounts to cut off and weld back on.
No warped tubes from too much heat, no crooked perches...clean and simple.
Ask Mav about welding perches. And he got a "pro" to do his.
For 4" lift and under, not worth the trouble cutting/welding in my opinion. Bigger than 4" you need to move perches so it's all a moot point if over 4" lift.

What you save from the initial purchase can be used for lockers, tires or beer.
I have less than $450 in both my fresh diffs with new rear axles, seals, bearings and brakes.

I was able to get bigger brakes and keep my 6 lug rims.

They look bigger but they aren't.
There is only one brake drum for 6 lug 9.5 14SF in '88-'98. 2wd or 4wd.
Brakes are same size as 10 or 12 bolt you took out. Same shoe, same, part number. 11-5/32" x 2-3/4" Even same hardware kits.
E-brake is same with side pull cables. '86(?)-'91 Blazer/Jimmy cables fit right into 14Sf backing plate and with same shoe as 10 bolt, it's like it was born there.
As for track width, unless your pulling u-turns in your driveway you won't notice a difference in radius at all.
It will however ride better and track better. I found that the tar strips or rain grooves on the highway would throw the truck around. Now straight an arrow @ 75.
End of the day, do what you want or use what you can find.

 

[thaboss801]

I can understand that. You must be in a different part of the country. Those trucks are falling off the trees here.

To each their own, providing some information and pictures to finish the thread.

 

[thaboss801]

I didn't think the h2 used the 14bsf axle. Is there anything different than a normal carrier change for the e locker

 

[Irish1941]

Nothing really different except the wiring and clip inside the diff that mounts on the bearing cap. I have an exploded view somewhere.
Loads of info online about swapping one in or read GM H2 manual.
The 9.5 is same center section wise all the way thru to '07 that I know of and perhaps even to current models. They are a pretty rugged axle.
Lot of guys have put them in the front in place of the stock AAM 9.25.

 

[jeff in co]

Nothing really different except the wiring and clip inside the diff that mounts on the bearing cap. I have an exploded view somewhere.
Loads of info online about swapping one in or read GM H2 manual.
The 9.5 is same center section wise all the way thru to '07 that I know of and perhaps even to current models. They are a pretty rugged axle.
Lot of guys have put them in the front in place of the stock AAM 9.25.

Yea, Irish pretty much hit everything (as he helped me out quite a bit during my conversion). I bought a front and rear axle set from a 91' 3/4 suburban with 4.10 gears.

I had a shop install the e-locker (from an H2) and re-set up the gears. Used a 1/2" spacer plate and everything else swapped over.

I took everything from my 6-lug front axle and swapped that over to the new one. Everything from the knuckle out.....worked like a charm!

 

[Blue85]

Personally I don't know why you'd want to convert an older 8 lug 14bsf to 6 lug

Personally, I don't know why you would plan out a new rear end and still have drum brakes.

Just find one with the gears you want, get the axle shafts you want and adjust the disc brake bracket to match.

OK, I can see reusing them because they're good and on-hand - but I can't see paying for new drums and parts.

 

[Blue85]

They look bigger but they aren't.
There is only one brake drum for 6 lug 9.5 14SF in '88-'98. 2wd or 4wd.
Brakes are same size as 10 or 12 bolt you took out. Same shoe, same, part number. 11-5/32" x 2-3/4" Even same hardware kits.

The 3/4-ton 80's 14SF had bigger brakes. Much bigger than 1/2-ton stuff. And I think there were two sizes for those.

 

[Irish1941]

The 3/4-ton 80's 14SF had bigger brakes. Much bigger than 1/2-ton stuff. And I think there were two sizes for those.

You're right, 11" & 13" '81 thru '87, but I wasn't talking about the '80s 14SF 8 luggers.
I was talking the '88-'98 14SF 6 lug.
There is only one size brake shoe & drum for '88 & up GMT 400 series 14SF 6 lug, 2 or 4WD, and that rear uses the same 11-5/32" x 2-3/4" brake shoes as 10 bolt.

 

[Blue85]

I'm not disagreeing, just adding information. I've never heard of anybody welding and re-drilling the bigger drums to run 6-lug, but it should be possible. (IIRC Moser Engineering actually gave me a quote to do this many years ago.) I know some people stick with drums for the parking brake and if you were towing with a 14Bsf you would be interested in the bigger brakes. If you modified the axleshafts at the same time, no mods to the backing plates/mounts would be required. It sounds like aftermarket 6-lug shafts could also work.

 

[kennyw]

I've never heard of anybody welding and re-drilling the bigger drums to run 6-lug, but it should be possible. (IIRC Moser Engineering actually gave me a quote to do this many years ago.)

It is difficult to overlay the two patterns while leaving enough material for strength. It can be done, but I consider the material left to be marginal.

 

[aandpman]

Was wondering - where/who did you get the backing pate spacers from?

 

[jeff in co]

Was wondering - where/who did you get the backing pate spacers from?

I used Cutthroat 4x4 to make the spacers. Be sure to specify 1/2" thickness.

Their website just spins and doesn't load for me but who knows. Their eBay store is still active. I had to call them and ask for the spacers to be fabricated. About $35 shipped.

 

[aandpman]

Thanks f

I used Cutthroat 4x4 to make the spacers. Be sure to specify 1/2" thickness.

Their website just spins and doesn't load for me but who knows. Their eBay store is still active. I had to call them and ask for the spacers to be fabricated. About $35 shipped.

or the quick reply. Taking a 14 sf, open diff, 3.73's home tonight and gonna commence on the rebuild/mods asap. Thanks again for all the good info.

 

[aandpman]

So from looking at the GMPartsDirect part numbers, it appears that the 88-up backing plates are the same for the 1500's and 2500's, so they don't have to specifically be from a 14sf ? That would greatly expand my pool of donor vehicles...

Check out here...(not that I'd buy from GMPartsDirect, just looking up numbers there...)
http://www.gmpartsdirect.com/chevro...-scat/?part_name=backing-plate&position=right

 

[aandpman]

Getting confusing. Does anyone have the correct part numbers for the backing plates to do this conversion?

 

[Blue85]

You're converting from 8-lug drums to 6-lug drums? If what Irish says above is true you can just move all the 10-bolt parts over. Has anybody ever confirmed they've done this? The axleshaft is longer, but the spacer might be all you need for that. If you're going disc you don't want factory backing plates.

 

[NorCalAnthony]

You just need the part number for the backing plate on a 88-up 6 lug SF right? I can try checking for you when I get home, I have one sitting in my garage that I'm about to convert to discs before I swap it under my K5.

 

[aandpman]

Yes. So to be clear, what I have is an 80's 14bsf that currently has 8 lug axle shafts, and had the 13" brakes. ~67" wms to wms.
My old DEAD axle is an 80's K5 10 bolt with 11.xx drums. If what Irish says is true (and I don't doubt him), I need to pull backing plates, shafts, and drums off a 88-98 model with 11.xx" brakes. I also wonder if the older 10 blt stuff would move over...

 

[jeff in co]

Yes. So to be clear, what I have is an 80's 14bsf that currently has 8 lug axle shafts, and had the 13" brakes. ~67" wms to wms.
My old DEAD axle is an 80's K5 10 bolt with 11.xx drums. If what Irish says is true (and I don't doubt him), I need to pull backing plates, shafts, and drums off a 88-98 model with 11.xx" brakes. I also wonder if the older 10 blt stuff would move over...

Yes, this is what I did. The FF backing and drums are bigger than the SF backing and drums. I did pull the SF backing, axle shafts and drums from a later model (88-98) axle.