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14 bolt sf question

crashandburn

crashandburn

1/2 ton status
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Dec 6, 2007
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Location
Colorado Springs, CO
I'm getting a free diesel K5 parts truck. Body is shot, motor is good, and it has a 14 bolt sf in it, and he says its a locker, so I'm assuming gov-bomb. But it's a 14 bolt and I'm only running 35's and I don't wheel it too hard, so I think I should be ok... Besides, we all know the drill. If it breaks, it wasn't strong enough, so build it better.
Anyways, this truck has 8 lugs in the rear and 6 in the front. I'm not digging that. What is the easiest, most cost effective way to switch to 6 lug, bearing in mind that here in CT, the junkyards are mostly late model stuff.
How about adapters?
Are all 14 bolt sf 6 lug axles the same? I understand that they are longer. What do I have to do to make them work? Do I have to switch to disk? Are they all disk?

Also, do you think 3.73's are enough gear for 35's with a diesel? I do plan on running a turbo soon.
 
crashandburn said:
10 bolt front end. Do they make 8 lug for those?
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Yes, get the caliper brackets and bearing hub/rotor assemblys, everything else is the same. I have tried to swap 8 to 6 lug on the 33 spline 14 bolt rear and everything is different.
 
Yup, lots of work involve to swap 8 to 6 lug. 8 lug stuff bolts right on to your 10 bolt though, well worth the upgrade!

The 14BSF is good for 40" tires bone stock, it'll laugh at your 35s
 
The 14-bolt SF is a great upgrade from the 12-bolt. And,the Gov-Loc is not a bad device,if you know how to use it right and don't expect locker performance from it. Not everyone rock crawls,I don't. I have a G80 in my '91 Suburban 3/4t w/35s and it serves me well. You just have to let the tires spin real easy until it kicks in. Then you can give it all you want. It's like a brush chipper,only opposite. If you stuff brush in,then turn it on,it will stall. If you start it up,rev it,then stuff the brush...POOF! Instant mulch! You just have to understand what you have and use it accordingly.
 
If possible, I would rather stick with 6 lug, so I don't have to buy rims on top of everything else. It seems like I have to convert one axle regardless, so I might as well convert one end and be done with it, rather than convert one end and then get rims.
 
It is easier to swap the front to 8-lug then swap the rear to 6. When you price new wheels, look around to see how much you could sell the old ones for. You know figure out the total price.

For the rear 6-lug swap, you just swap axleshafts and brake drums from a 6-lug version. There was more than one size of drum, and the shaft lengths matched them, which makes it easy. The hard part is that the rest of the brake hardware has to match. I'm not sure what the variations were and if there was more than one location for the brake mounting on the axle tube. Now if you wanted to disc brake at the same time things get even easier. Don't buy new drums anyway without looking into this. This has all been covered many times. SEARCH.

Forget about wheel adapters. You can't get an 8-lug to 6-lug adapter. It can't really be built.
 
I swapped a '93 14 bsf (6 lug) into my 91 K5. Little bit wider than than the stock 10 bolt rear. You have to move spring perches and shock tabs, but brakes worked great. Was even able to swap the yoke from my 10 bolt so didn't need a conversion u-joint. Might be an easier choice than converting the 8 lug to 6 since you will need to find the axle shafts and brakes anyway.
 
72blazerguy said:
I swapped a '93 14 bsf (6 lug) into my 91 K5. Little bit wider than than the stock 10 bolt rear. You have to move spring perches and shock tabs, but brakes worked great. Was even able to swap the yoke from my 10 bolt so didn't need a conversion u-joint. Might be an easier choice than converting the 8 lug to 6 since you will need to find the axle shafts and brakes anyway.
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I am doing the same thing. Putting a 14bsf into a 91 K5. My donor axle came out of 92 C2500 light duty truck. The width is almost exactly the same if not a touch wider (like that), the yoke swaps on for the driveshaft (as mentioned), and the ebrake cables will swap over. The only thing I am concerned about is the driveshaft length, as the 14bsf is a bit larger. The new spring perches have the ability for adjustment though. Finding one with the right gear ratio and in good shape was the biggest challenge. Tried car-part dot com but ended up with this one off of a local wheeling board.
 
I converted an 8 lug 14bsf to 6 lug and in my opinion it was not worth it. Lots of parts chasing, comparing, measuring, ordering, returning wrong parts, re-measuring, re-ordering, and once it was all together the axle shaft bearing surfaces don't fit exactly perfectly on the bearings. Will it work yes, would moving spring perches and shock mounts be easier, yes.

I have the conversion in my build thread somewhere in the middle if you wanna search for it.
 
sry to thread hi-jack, but....
ive got a chance at a free 6 lug 14bolt sf wondering if its worth it? it would be replacing a well worn 12 bolt are they
 
gearing: probably depends on how the rest of the truck is geared. I've got an 86 M1028 CUCV with a TH400 and 4.56's and on stock tires the thing screams going down the highway. I've thought about 3.73's with 35's since they're a pretty nice happy compromise between low-end torque and top-end speed (max speed with 35's= around 75mph) I really have no need or want to go faster than this.
 
I've never run 35s with anything taller than 4.10s (which netted right about 3.73). I think 3.73s would be pretty lame and a turbo won't help on the bottom end. Don't the CUCVs run 3.73s? My son runs one of those with 11.50/32s. It's does all right,but I'm thinking 35s would dog it. It might be ok,but not for me.
 
super k said:
I've never run 35s with anything taller than 4.10s (which netted right about 3.73). I think 3.73s would be pretty lame and a turbo won't help on the bottom end. Don't the CUCVs run 3.73s? My son runs one of those with 11.50/32s. It's does all right,but I'm thinking 35s would dog it. It might be ok,but not for me.
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The pickups ran 4.56
The Blazers have 3.08
 
After all that, the truck turns out to have a 12 bolt in it. I told the guy to keep it. The search is on for a 6 lug 14 bolt sf, and if I can find one with 4.56's and a locker of some sort, that would be awesome.
 
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