OBS to NBS k2500 Hub Swap Possible?

[dv8lad]

Hi,
First post, so please be gentle. I have a 2000 OBS HD K2500 RCLB owned since new. I love my truck, but absolutely hate, hate, hate, the brakes. The rotors warp easily, I do a lot of towing, never off-road, and live in Detroit (salt city). I hate tearing the hub assembly apart to change rotors. Is it possible to switch the 8 lug hubs from my vehicle to the 8 lug hubs from a NBS truck/subruban/avalanche? I was wondering if the 4 hub to knuckle bolts were in the same location on the NBS hubs? Will this require the use of NBS rotors? Will the rotors fit under the OBS calipers and work? Would I have to change over to the NBS knuckle/caliper bracket and caliper to make it all work?



I know its a lot of questions and I have done several searches, but came up with nothing.

[Blue 04 Z71]

Bolt pattern is the same 8 on 6.5. The new axle spring perches are in different locations so those will need to be moved and welded back on. And as for the hubs im not sure on the bolt pattern to mount them. I know on my 1500 there is only 3 hub mounting bolts.

[dv8lad]

Bolt pattern is the same 8 on 6.5. The new axle spring perches are in different locations so those will need to be moved and welded back on. And as for the hubs im not sure on the bolt pattern to mount them. I know on my 1500 there is only 3 hub mounting bolts.

Thanks for the quick reply. Ok, i guess I get to keep my rims, check. I didnt want to swap axle housings, just the axles that reside IN the housings. Since the lug bolt pattern is the same, I dont need to do that now, check. If you look up a 4x4 2500 NBS, you will see that they are a 4 bolt mounting pattern for the hubs.


Thanks.

[454cid]

Bolt pattern is the same 8 on 6.5. The new axle spring perches are in different locations so those will need to be moved and welded back on. And as for the hubs im not sure on the bolt pattern to mount them. I know on my 1500 there is only 3 hub mounting bolts.

He's talking about the front...... there are no spring perches, or even springs.

[454cid]

..............Is it possible to switch the 8 lug hubs from my vehicle to the 8 lug hubs from a NBS truck/subruban/avalanche?

Yes, it's possible but you end up using a lot of GMT-800 parts, and it's not simple bolt on. You need the knuckles, rotors, calipers, and I think CV shafts for a GMT-800. The knuckles need to be modified becasue the ball joints are different. You'll also need to figure out new tie-rods. Ponykiller is the only person I know that's actually done it.

[Blue 04 Z71]

He must of edited it because he did say something about the rear about changing axles to match the front bolt pattern because he thought they were different.

[dv8lad]

Thanks for the replies, I modified my search terms and it led me to here: w w w.vortec454.com/index_files/Page697.htm I did try searching for Ponykiller's posts but did not have time to skim through 490+ pages of that thread. The link I referenced, is absolutely the way I will go with my brakes as far as the front is concerned. The rear brakes will be determined after more research. In the next couple of days/week, I will source the parts and do the modifications to the knuckles/hub carrier for the ball joints' proper fitment. I will take plenty of pics and provide an updated write-up/walk-through when the project is completed. I thank you guys again for helping me out so far. I can't wait to get this done.

[454cid]

It's actually Ponykiller87, I just couldn't remember the number.

http://www.fullsizechevy.com/forum/m...r87-12529.html

vortec454.com is his website, but it doesn't work very well.

[97sierra454]

Thanks for the replies, I modified my search terms and it led me to here: w w w.vortec454.com/index_files/Page697.htm I did try searching for Ponykiller's posts but did not have time to skim through 490+ pages of that thread. The link I referenced, is absolutely the way I will go with my brakes as far as the front is concerned. The rear brakes will be determined after more research. In the next couple of days/week, I will source the parts and do the modifications to the knuckles/hub carrier for the ball joints' proper fitment. I will take plenty of pics and provide an updated write-up/walk-through when the project is completed. I thank you guys again for helping me out so far. I can't wait to get this done.

I spent a year + researching this, and I am completing the swap this week with parts from a 2004 K2500HD. Basically finished just need to bleed the brakes. If you are still considering this I can provide some assistance; I may post on this on the forum after its complete. Its not cheap and its some work, but it requires very little fabrication and alteration. I differed in what Ponykiller did in that I used the 2004 K2500HD lower control arm rather than alter the lower ball joint taper seat.

[454cid]

I spent a year + researching this, and I am completing the swap this week......

Please do a write up with lots of pictures! I've researched it a bit, but haven't had the funds to actually do it. I've love to see another truck done.

I still have the 05 knuckles I bought for this purpose, sitting in my garage,

[97sierra454]

Please do a write up with lots of pictures! I've researched it a bit, but haven't had the funds to actually do it. I've love to see another truck done.

I still have the 05 knuckles I bought for this purpose, sitting in my garage,

I'll try to do that. I've learned ALOT and I think what I did is a bit better and easier than what Ponykiller did. For example, one "secret" I learned while cross referencing parts is that you can use the spindles ONLY from the 99-00 2500 NBS Non-HD (it was the oddball pre HD 2500 in the new body style), and then the taper seat for the tie rods is EXACTLY the same as your OBS tie rods. They only differ from the newer HD spindles in the tie rod taper seat. This is much easier than using aftermarket steering linkage, and I can tell you that upgrading to the newer style tie rods is NOT feasible.

[454cid]

I'll try to do that. I've learned ALOT and I think what I did is a bit better and easier than what Ponykiller did. For example, one "secret" I learned while cross referencing parts is that you can use the spindles ONLY from the 99-00 2500 NBS Non-HD (it was the oddball pre HD 2500 in the new body style), and then the taper seat for the tie rods is EXACTLY the same as your OBS tie rods. They only differ from the newer HD spindles in the tie rod taper seat. This is much easier than using aftermarket steering linkage, and I can tell you that upgrading to the newer style tie rods is NOT feasible.

Well, that sounds like I've got the wrong knuckles then, since mine are from a 2005. I wouln't dream of using GMT-800 HD steering linkage....... they're known for bending. The centerlink is spaced differently any way, I think.

I've kicked around the idea of simply doing an SAS, but then I come back to reality and realize that's a pretty big project considering I can barely afford to pay attention, much less pay for a Dana 60, and the associated parts needed to pull that off.

[97sierra454]

Well, that sounds like I've got the wrong knuckles then, since mine are from a 2005. I wouln't dream of using GMT-800 HD steering linkage....... they're known for bending. The centerlink is spaced differently any way, I think.

I've kicked around the idea of simply doing an SAS, but then I come back to reality and realize that's a pretty big project considering I can barely afford to pay attention, much less pay for a Dana 60, and the associated parts needed to pull that off.

Well, you can buy just the bare 99-00 2500 spindle castings, and then use all of the other parts you already had from the 05 like the wheel bearing, brake dust shield, etc etc.

[97sierra454]

A few before pics:




Stripped down to bare bones:

[97sierra454]

And a few after:

[97sierra454]

Close ups:

[454cid]

Well, you can buy just the bare 99-00 2500 spindle castings, and then use all of the other parts you already had from the 05 like the wheel bearing, brake dust shield, etc etc.

All I have are the knuckles....... I bought them off of ebay, from a guy that had installed a lift.

I don't call them spindles since the spindle is part of the CV shaft on a 4x4....... Spindle is more a 2wd part name in my opinion.

[454cid]

Looks great...... so that lower control arm is GMT-800? What did you use for CV shafts? What about the upper ball joints?

[97sierra454]

Looks great...... so that lower control arm is GMT-800? What did you use for CV shafts? What about the upper ball joints?

I know what you mean but the interchanges like Hollander classify them as spindles so that's the only reason I call it that.... but you get the idea.

Yes the lower control arm is 800 series, in my case from a '04 K2500HD. You can do this and slightly alter the old shock bracket to fit the 800 series control arm, or, what they did in that link which was to use the 400 series lower control arm and cut out the taper seat on the 800 series knuckle/spindle lower ball joint seat. I chose to use the proper ball joint and alter the shock bracket instead.

Upper ball joint is stock OBS; you MUST use the OBS upper control arm. The geometry of the upper arm is totally different on NBS so its not even an option, although it would not fit anyway. The NBS spindle/knuckle taper seat MUST be cut to be used with the OBS upper control arm/ball joint. Luckily with the right bits and a cordless drill, it took 10 minutes to alter perfectly.

CV shafts are from the '04 K2500. You must use the newer CV's as well to align with the newer style wheel bearing. The good news is the newer CV's bolt right to our existing OBS carrier with NO mods required.

[454cid]

Yes the lower control arm is 800 series, in my case from a '04 K2500HD. You can do this and slightly alter the old shock bracket to fit the 800 series control arm.....

The shock hadn't occured to me. Not having seen the two lower control arms side by side, it looks like it might be the same forging, just machined differently.

, or, what they did in that link which was to use the 400 series lower control arm and cut out the taper seat on the 800 series knuckle/spindle lower ball joint seat. I chose to use the proper ball joint and alter the shock bracket instead.

Are you talking about Ponykiller?

Upper ball joint is stock OBS; you MUST use the OBS upper control arm. The geometry of the upper arm is totally different on NBS so its not even an option, although it would not fit anyway. The NBS spindle/knuckle taper seat MUST be cut to be used with the OBS upper control arm/ball joint. Luckily with the right bits and a cordless drill, it took 10 minutes to alter perfectly.

Originally, I thought maybe the upper arm would interchange, but I found the mounts to be totally different as you mentioned. I was hopping to stay away from having to alter the tapers, but that doesn't sound too bad....... it was the lower one that Ponykiller ran into problems with.

CV shafts are from the '04 K2500. You must use the newer CV's as well to align with the newer style wheel bearing. The good news is the newer CV's bolt right to our existing OBS carrier with NO mods required.

Having the new hubs with the slip on discs would be awesone......... and then those dual piston calipers, maybe I'd finally have decent brakes.