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GM 14 bolt swap into 91 Burban.

pma4x4

pma4x4

AKA Yankeeroad
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My question is this.

I can get a hold of a 78 GM 14 bolt with 4.10s (which is what i want to regear to anyways) for cheap. I want to put it under my 91 suburban 1500 that currently has a 10 bolt.

Do i need to move the springs perches and the shock mounts? would I need to change the shock mounts?

Welding and fab work doesn't scare me.

yes I know the bolt pattern is different so I am thinking easiest would be to just change hubs and rotors out on front end. I don't have my choice of wheels yet so that doesn't matter either.
 
I pulled my 14 bolt out of a 74' burban to put in the K5. It bolted right in place no need to move the perches. It all comes down to the difference in 3/4 and 1 ton.
 
Your best bet would be to find a matching set of 3/4 ton axles. Way less work than regearing the front.

Martin
 
As mentioned, it depends on the origin of the axle. 1/2 and 3/4 ton trucks have a wider spring perch spacing (42.5" center to center, if memory serves) than the 1-ton (40.5", again, unless my aged brain farted.)

Shock mounting differs from 2WD to 4WD.

The best match to your Suburban, then, would come from a 3/4 ton 4WD, which would bolt right up.

An axle from a 1-ton would require moving the spring perches (major ugh), and from a 2WD would require fiddling with the shock mounts (less ugh.)

HTH.

-- A
 
TheBeast_88K5 said:
Mine was 40.5", I believe...
Click to expand...

Which means it came from a 1-ton which is why you had to move the perches.

The only weird thing is the "3/4" crewcabs, which have the same frame as a 1-ton (and the same narrower spring spacing.) But I was trying not to confuse the OP :D

-- A
 
I just put a 78 3/4 ton 14b ff in my 87 Burb, converting to discs at the same time being the drums were shot. Like stated, the 3/4 ton 14 b will bolt right in. I ended up finding a donor front 3/4 ton axle in the same gear and just swapped all the parts to my current axle to get the 8 lugs, probably more work than just swapping axles but I had just gone through my current axle, so opted to just swap from the knuckles out and gears. I have a set of front axle 4.10s sitting in the garage if you are needing a set.
 
The first one i found the guy said it was out of a '78 3/4 ton 8 lug saying it s a FF.

I just found another sale on CL. a matching set from a 3/4 ton with 410s but I asked him for details since he just said 3/4ton axles out of a 78.
 
Well I am always thinking of just going with original plan. Keep the axles. gear them. ARB the rear move the limit slip to the front and have a spare set of shafts on hand, which I will have spare shafts with the rig at all times no matter what axle I have. Truss up the 10bolt housing and maybe get some better shafts.

I am not crawling nor WOT mudding with it. its an expedition rig with 33s maybe 35's. so I think the 10 bolt should do. Unless I come across a great deal on 3/4s They go quick so I am looking.
 
If that's what you use it for, I think the stock axles would hold up fine. It sounds like you already take the standard precautions so you don't run into big issues out in the boonies. Is that a gov-lok lmited slip you have in there now? Also, you better just stop reading now or else before you know it you will be convinced tons are a necessity and 44s are the best set up for your expo rig :D
 
jwobbs said:
If that's what you use it for, I think the stock axles would hold up fine. It sounds like you already take the standard precautions so you don't run into big issues out in the boonies. Is that a gov-lok lmited slip you have in there now?
Click to expand...

I actually dont know right now. I am picking it up next week.
 
Ok, I just know the gov-looks can be touchy so you want to make sure you get it to engage slowly, ie don't have one wheel on ice and the other on concrete and goose it because it'll slam in and has a tendency to break.
 
For the price of re-gearing, you can usually own a set of properly geared 3/4 ton axles for much cheaper.

Martin
 
Ok, I may have a line on a 1990 3/4 ton burby for parts. From what I understand is that the rear will be a 14 bolt drum and the front a 10bolt with 3/4ton outers. I will need to verify it has 4.10s first

Here is the trick question. can I get 15x8 with a 4" backspacing to work? with minimal grinding?

I have a pretty much new set of (5) 33x10.50x15 BFG ATs from my Jeep I am selling.
 
pma4x4 said:
Ok, I may have a line on a 1990 3/4 ton burby for parts. From what I understand is that the rear will be a 14 bolt drum and the front a 10bolt with 3/4ton outers. I will need to verify it has 4.10s first

Here is the trick question. can I get 15x8 with a 4" backspacing to work? with minimal grinding?

I have a pretty much new set of (5) 33x10.50x15 BFG ATs from my Jeep I am selling.
Click to expand...

The front axle on that truck would be ideal for your purposes.

The rear, however, will likely be a 14 bolt semi float, which is less desirable. If you're gonna go through all the work, may as well get the big kahuna, the full floater. You can easily determine which it is by either examining the pumpkin (see http://coloradok5.com/axleguide.shtml )

Semifloater:

gmcorp14bolt9.jpg


Full floater:

gmcorp14bolt10.jpg


Also on the full floater, the wheel hub protrudes through the center hole of the wheel and has eight bolts on the end, versus the semifloater doesn't go past the drum.

-- A
 
Thanks Dremu, that info helps me a lot, kind of answers some questions!

I have not looked at the donor burby first hand yet just some picks but it appears there is no protruding hub on the rear axle.

But if it turns out to be 4.10s I am not sure if I should pass this up. I mena either ways its far better then a 10 bolt rear.
 
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