3/4 ton axles

[stm3784]

I posted about about a rusty frame in another thread. It was a k20. The build I want to do is a k20. Anyway someone had mentioned using a k10 and doing an axle swap. I was planning on doing that already if I couldn't find a decent 3/4 ton. The question is, can I use newer axles and springs? Newer being like 88 and up? Or do I need to stay in 73-87? If I can do this with the newer axles, is there any fabrication involved?

 

[Honky Kong jr]

I posted about about a rusty frame in another thread. It was a k20. The build I want to do is a k20. Anyway someone had mentioned using a k10 and doing an axle swap. I was planning on doing that already if I couldn't find a decent 3/4 ton. The question is, can I use newer axles and springs? Newer being like 88 and up? Or do I need to stay in 73-87? If I can do this with the newer axles, is there any fabrication involved?

You can use 88-91 burban 3/4ton axles. Not 88 up roundy body trucks rear axle could work with modifications and IFS screw that noise lol.

 

[Rusty Nail]

3/4 axles are the same as 1/2 axles with more lug studs....no real point in that swap unless youre after a 14 bolt or something. But whatever floats your boat!

One tons are different, but you werent talking about that.

 

[HotRodPC]

Hopefully this info I'll give will help you out, cuz I already know being in PA, you're in big trouble already just trying to find a K series truck that's not half rusted away. Then on top of that, wanting a K20, makes it even harder yet since the K10's are probably 3x more available than K20's.

So, I'm doing the same thing with my K10/20 project. It's originally a K10 but I'm converting it to 3/4 ton springs and axles. My conversion in my opinion, will even be better than a K20. Here's why. K20 trucks come with 52in springs like the K10 springs, just stiffer and stronger. The C20's come with 56in springs. Stronger spings, but longer so should offer a better ride.

The long bed K10 frames are punched to use either 52in or 56in springs. So I'll be drilling the rivets to the rear spring hangers and moving them back 4in to the other set up holes put there by the factory. Then installing the 56in C20 2wd 56in 3/4 ton C6P springs. Should give me a little more lift, heavier spring capacity and yet keeping a smoother ride with the longer springs.

Then I'm using a 14b Full Float axle out of 85 C20. The front springs, I'm using Rancho 4in lift springs for K10/K20. I can use the same front axle, I just have to swap the 6 lug hubs and brakes for 8 lug brakes and hubs.

Then use a K20 driveshaft or use a conversion U Joint and you'd all the powertrain of a K20 in a K10. In some states, it's better to do it that way since the higher the GVWR, the higher the annual tag is. Cali is one of those states for example. Though in Cali, higher GVWR means it can run dirtier too and still pass smog. So pros and cons either way, but it's not hard to convert a K10 to K20.

 

[stm3784]

You can use 88-91 burban 3/4ton axles. Not 88 up roundy body trucks rear axle could work with modifications and IFS screw that noise lol.

Lol. That's what I thought. Thanks

 

[stm3784]

3/4 axles are the same as 1/2 axles with more lug studs....no real point in that swap unless youre after a 14 bolt or something. But whatever floats your boat!

One tons are different, but you werent talking about that.

Just looking for the higher gvxr/gcwr

 

[Craig 85]

Remember, if you do a 14 bolt swap (full floater or not) you will need larger u bolts and spring plates as the axles are larger in diameter tha the 1/2 ton. Here's the rear u-joint I used to adapt my 1/2 ton drive shaft to the 3/4 ton rear end on my '79. Spicer 1310-1350 Part# 5-460X or O’Reilly’s Precision U-joint Part# 348

 

[bucket]

3/4 axles are the same as 1/2 axles with more lug studs....no real point in that swap unless youre after a 14 bolt or something. But whatever floats your boat!

One tons are different, but you werent talking about that.

As far as the front axle is concerned, that's true. The advantage though is the much bigger rotors (more stopping power) and the usual set of 3/4 ton axles have 3.73 or 4.10 gears instead 3.08 like a lot of 1/2 ton trucks got. And losing a 10bolt rear axle is always nice.

 

[jetman]

3/4 axles are the same as 1/2 axles with more lug studs....no real point in that swap unless youre after a 14 bolt or something. But whatever floats your boat!

One tons are different, but you werent talking about that.

The 3/4 and 1/2 ton axles up front (corp 10 bolt) are identical internally, the only diff is the hub (8 vs 6 lug). Most 3/4 front disks are the same as 1/2 tons, the exception is that 3/4's with higher GVWR do have the larger disks.

On the rear, things are different on 3/4's. Having either 9.5" ring on 14 bolt SF (vs 8.5 ring on 10 bolt) or 10.5" ring & improved pinion support on FF. Both having larger tubes and axles than 10 bolt and of course much more capable drum brakes.

 

[HotRodPC]

The 3/4 and 1/2 ton axles up front (corp 10 bolt) are identical internally, the only diff is the hub (8 vs 6 lug). Most 3/4 front disks are the same as 1/2 tons, the exception is that 3/4's with higher GVWR do have the larger disks.

On the rear, things are different on 3/4's. Having either 9.5" ring on 14 bolt SF (vs 8.5 ring on 10 bolt) or 10.5" ring & improved pinion support on FF. Both having larger tubes and axles than 10 bolt and of course much more capable drum brakes.

I wish I had parts to play with so bad. I've been looking for an 8 lug 10 bolt for a couple of years. Either they're way to far away or way to much money and fuct up.

I did do a parts look up comparison at one time. I seen that the pads are the same, the calipers are the same, bearings are the same, locking hubs are the same. Only difference I seen was the rotor. Of course, 1 has 6 lugs and 1 has 8. So I gather that if I was to use the lighter duty 3/4 ton K20 front brakes, is it possible that all I'd need to change is the rotor and luck out and backing plate be the same too?

If I had both sets of parts I could do this comparison to find out but I don't.

 

[bucket]

Nope, all K20's use a larger rotor than a K10.

 

[bucket]

Also, most (if not all) K20 calipers have a slightly larger piston. But they do interchange.

 

[jetman]

So I gather that if I was to use the lighter duty 3/4 ton K20 front brakes, is it possible that all I'd need to change is the rotor and luck out and backing plate be the same too?
.

Yes, the lighter duty front axle K20 is the EXACTLY same as a standard K10 axle. The only difference being two (2) additional studs on the rotor. The backing plates, calipers, pads, backing plate, disk dia, bearings, seals etc is EXACTLY the same and interchangeable.

There are some higher GVWR rated K20's out there which have a larger dia rotor, which are really cool if you need some heavy duty binders. Hence their pads, backing plate and I believe the caliper is different to fit the larger dia rotor. With that said, the balance of the heavy duty K20 axle assembly is EXACTLY the same as the light duty K10 front axle.

 

[HotRodPC]

Nope, all K20's use a larger rotor than a K10.

Also, most (if not all) K20 calipers have a slightly larger piston. But they do interchange.

I sure hope you're wrong about this. If you're wrong and Jetman is right, then I can get by with simply buying new 8 lug rotors. Damn, I hope so. I'd prefer bigger brakes, but that can wait for later on after I get the truck built, running and legal. Then I'll consider a brake upgrade later on. I wonder if this truck might have bigger K10 brakes anyway. Remember, it was OEM diesel and has Hydroboost. Maybe the Hydroboost will default the front brakes to the bigger of the K10's and be equal to K20 smaller brakes.

Yes, the lighter duty front axle K20 is the EXACTLY same as a standard K10 axle. The only difference being two (2) additional studs on the rotor. The backing plates, calipers, pads, backing plate, disk dia, bearings, seals etc is EXACTLY the same and interchangeable.

There are some higher GVWR rated K20's out there which have a larger dia rotor, which are really cool if you need some heavy duty binders. Hence their pads, backing plate and I believe the caliper is different to fit the larger dia rotor. With that said, the balance of the heavy duty K20 axle assembly is EXACTLY the same as the light duty K10 front axle.

That would be so awesome if you're right. Then all I gotta do is buy K20 rotors.

 

[bucket]

Yes, the lighter duty front axle K20 is the EXACTLY same as a standard K10 axle. The only difference being two (2) additional studs on the rotor. The backing plates, calipers, pads, backing plate, disk dia, bearings, seals etc is EXACTLY the same and interchangeable.

I'm sorry but this is just plain wrong. The 8-lug bolt pattern alone requires a larger diameter rotor. Beyond that, the 8-lug hub has a wider track built into it, requiring different backing plates even IF the rotors were the same diameter.