Anyone beefed up a 12 bolt rear?

[Destructo]

Instead of going with a 14bFF axle i'm actually just thinking about beefing up my 12 bolt with some axle shafts and u-joints. That way I keep my weight down and keep my ground clearance. And plus I won't need new wheels and all that crap.

I'm planning on running a 35x12.5" tire which with axle shafts and stronger u-joints I should be ok long as I don't get too crazy with the skinny pedal. And maybe beef up the joints in the front 10 bolt also, the axle shafts should be ok, but I think the joints are more prone to failure.

[IoWnZa]

I would go with the 12 Bolt, just cause a 14bff would be too much for only 35's, maybe 38's and up, but not 35's I wouldn't think.

Anyways, I beefed my 12 bolt up real nice with heavy duty axle shafts, U-Joints, and of course an all new Carrier, and Eaton Limited Slip Differential unit. I have 32x11.50's on it now, but I might go to 33's or 35's sometime in the Future if I decide to lift the Blazer.

[69k5]

get a 14sf for 70 bucksd here at the jy. stronger than the 12 but not nearly as big as a 14ff and you can keep the 6 lug. best of both worlds.

69k5

[Destructo]

I'll be running a lunch box locker in mine, and a semi-floating 14 bolt has 8 lug axles. Maybe you can convert them to 6 or something?

[69k5]

i thought all sf have 6 lugs

[smokkey1]

my 90 sub has an SF and it's 8 lug. I think 92 and up are 6 lug not sure though...


justin

[Bill W]

Originally posted by 69k5
get a 14sf for 70 bucksd here at the jy. stronger than the 12 but not nearly as big as a 14ff and you can keep the 6 lug. best of both worlds.

69k5

I can't get a quote in Oregon for a 14 bolt SF for anthing less than $500. They tell me demand is high due to all the 10 bolt guys swapping out to the heavier axle.

Bill

[1FaastC10]

any pre-88 SF will be 8 lug, coincidentally, that is what will bolt directly into your truck. you *might* be able to get axle shafts, backing plates, and drums from a post 88 1/2 ton SF to work, which will allow you to retain your 6 lugs. personally, for what it would cost, in both money and time, to "beef" your axle, or convert a SF to 6 lug, and regear your axles for the larger tires. im tellin you man, you will be WAY happier with 3/4 axles. bolt them in, and call it a day. strength and regear all in one shot, and cheaper than you can buy the gears for.

[Destructo]

I'll have to do a lot of massaging of the 14 bolt though, i'm gonna lose a lot of ground clearance with it, which is of concern to me. I would have to run 38" tires on a 14BFF to get the same clearance as a 12 bolt with 35's. I read a article about beefing up 12 bolt to run with 35s and they had no major problems, I doubt the pinion will be a problem.

[drink2mny]

The only question to keeping the 12 bolt would be..................

Are you going to hardcore this truck..
You seem worried about clearance. Does that mean you are going to rock climb or or manuver through ruts..

Or just going on usual logging trails for hunting or something and not really playing in the mud.

I am the leader in learn from mistakes..
Quick redition of mY '86 blazers life
This will be short..
begins with 2" add-a-leafs and up arched speings in front to run 33's..Mind you 10bolt front and rear with 3.08's

Well that lasted not even a year from mild offroad. axles up front snapped, smoothed my spider gears in the front more than once..
Had enough with that thought I would step up..
Again still with 33's and a stock 350..
got a good deal on 4.10 12 bolt(10 bolt started to howl) and found a dana 44 with 4.10's..
Little better right>>>WRONG..played offroad for a bout 6 months and then spit the rear spiders out of the cover

Still popped spiders smooth up front.. these were all open diff's with 33's and no horsepower or lead foot.. She was my daily driver so could play hard at all.....

Oh yeah forgot, broke 2 short axles in the 44..

Pissed by now and wife hated the blazer..I got a good deal on 14 boltFF and went to junk yard for a set of 8 lug 15" rims
Had 6 lug up front for about3 months and found a 8 lug D44 to get the outers from..

That setup lasted a long time
I still have the same 14 bolt but yes I did upgrade to a D60 up front.. got tired of not owning stock in Dana Spider gears..They pop real easy in ruts with 1 tire spinning and 1 not.Then the tire spinning makes contact and SNAP.. no more spider gears..

This was all with 33's and mild offroad..and 2-2 1/2 in lift..
I never had a clearance problem with the 14 bolt.
1 because i never went in deep ruts bigger than my 33's..

of course it has taken me 4-5 years to get were she is now..
And no drivetrain problems with the 14 bolt..

Just a little info because it doesn't make sense if you need clearance if you don't plan to wheel hard

As for getting better axles.
You could put that money into 3/4 ton and have some left over..
beefy axles for 12bolt with C-clips in an oxymoron...


Not telling what to do, just offering advice..
Good luck..

[Destructo]

If I get a 14 bolt it will be cut and or shaved. Atleast to get rid of the rock grabbing lip. Right now this truck is a daily driver but will also be a fairly serious off-road truck, some rock-crawling and mostly trails, possibly with deep ruts, I ran through a muddy trail the other day which I plowed like a bull-dozer with my front diff. I'll be beefing up the front diff cover by welding some plate steel to it. So it is not a mud truck but is a rock/trail truck, thats why i'm concerned with the ground clearance, also a little concerned about weight, but am thinking about putting a flat-bed on it so that will remove some weight. Was thinking about doing a disc brake on a 14 bolt if I get one also, but I will need a E-Brake, I really don't want to be running without one, and putting an ebrake on a disc brake rear-end will be very expensive I think.

[drink2mny]

Blackbird's has built a couple rock crawlers, if you check out the site and go to trucks and video's page you'll see an orange willy we did..
Put a D60 in the back and a 44 up front..
but he runs 36's and or 37's..

And to answer your question about an ebrake 14 bolt. yes if you order a whole kit..We do sell them ( free shipping ). but you could probably make up something yourself and come across caddy calipers as cores to turn in when buying new ebrake calipers..

Again not that i'm telling what to do, but instead of using a 12 bolt for rocks and worried about clearance, you could look into a D44 rear. Much more stout.
Just a thought..

[robertwb]

you could always do the pinion mounted e-brake for the dana 60(or the 12 bolt)
TSM manufacturing

[Destructo]

I have a feeling that a rotor mounted right on the pinion will get smashed to bits, would have to be mounted up at the transfer case, and then I would probably have to convert to a non-slip yoke which they don't make for 208s yet.

And 540 dollars aint bad if I get everything I need and don't have to go to the parts store, it would be worth it to save some trouble and just have all new stuff.

If I put a 14 bolt under it then I will be putting a full-floater in it. And a Dana 44 is not really any stronger than a 10 bolt. Atleast for the front anyway, don't know about the rear-end. But its still only a 1/2 ton axle either way.

[1FaastC10]

14SF isnt as deep as a FF, the ring gear is 9.5" rather than 10.5", i dont think that they have the lip. my buddy has a SF that he just pulled out of his truck, i'll take a look at it next weekend and see how much it hangs down, im gonna guess no more than 3/4" lower than the 12 bolt with its 8.875" ring gear.

[ryan68]

I have stock 12-bolt parts and Dana 44 parts on my suburban with 35's and front and rear detroits, the front I just put in the newer 44 shafts that don't "neck down". I just broke a hub and that about it. And I wheel the hell out of them. The only problem I've had is power steering box seals, and keeping the rear axle from bending(twice now). I even have an under the carrier truss, helped a little in not letting it bend SO much. I've consider a Missouri Outfitters over the top truss, and you can abuse it all you want. That's my next upgrade for mine.

[1972C10]

I did a little wrenching On my nieghbors 93 gmc 2500 4X4 It has one of them "light duty 14 bolts" 6 lug they seem to be a tad larger axle than a 12 bolt but still taper down

Not near as strong as a full floater IMO but I was eyeballing it pretty hard thinking it would be a good upgrade for my 88 with a 10 bolt for the main reason same style 6 lug pattern Because i run 00 Z71 wheels and a old style 6 lug 12 bolt would require me to get the center of my wheels bored out .

Im not too sure if it would be worth the swap from 12 bolt to 14 bolt sf