NBS Front Brake Swap for OBS Trucks

[Coveman]

you need the nbs hubs to fit the nbs knuckles, so i went with nbs cv’s that fit right up.

the write up mentions bending the obs cv dust shield to fit, not sure how that works out.

 

[dfarr67]

I have nbs hubs and everything- the cv issue has been touched upon but not really in the detail I wanted. Do you remember if the nbs knuckles had just a through hole and relied on the nbs cv splash guard or was there some kind of seal to keep debris from entering through the back side?

 

[Coveman]

I have nbs hubs and everything- the cv issue has been touched upon but not really in the detail I wanted. Do you remember if the nbs knuckles had just a through hole and relied on the nbs cv splash guard or was there some kind of seal to keep debris from entering through the back side?

just a hole in the knuckle. the nbs design is a lot more “lean” than obs, pretty good sized air gap.

 

[dfarr67]

Well I have the seals coming, will see if they fit.

 

[dfarr67]

No problems whatsoever with the alignment. That's a good reason to do all the front end stuff at once I think since the alignment is needed after the knuckles, BJs, tie rods, pitman and idler arms. If any of those items are worn..nows the time to do em!

I bought new hubs and axles as well (fitment for the nbs trucks), not worn out but are different from our trucks so needed to be swapped.

The post by mike with thanks to rocky Thorton was my roadmap, it was very accurate and thorough. I'm a home garage wrencher and didn't run into any problems. The lower BJs were the toughest part of the whole operation, if you do them make sure you buy or borrow a decent press.

I did the NBS MC swap as well (before the knuckles). That would be essential for the new brakes / larger volume calipers.

I'm happy to answer any other questions, this was a really fun and satisfying project for me. Worst part of my rig was always those brakes!

So the old style seals are too small to fit the new knuckles- found a set of 05 CVs to use- everything went together OK. MC w/HB, disappointed in the soft feel vs the old 3/4 ton calipers, not sure if I got all the air out- or this is a typical feel, seems most have gone with a nbs MC. Haven't road tested or bedded in the pads yet tho.

 

[83GMCK2500]

So the old style seals are too small to fit the new knuckles- found a set of 05 CVs to use- everything went together OK. MC w/HB, disappointed in the soft feel vs the old 3/4 ton calipers, not sure if I got all the air out- or this is a typical feel, seems most have gone with a nbs MC. Haven't road tested or bedded in the pads yet tho.

Were the brakes bled with a bi-directional scan tool? The proper way to bleed the ABS involves cycling it electronically.

 

[dfarr67]

1989 K1500, whatever ABS was on it oem was taken off years ago.

 

[dfarr67]

For the nbs mc disk/disk, is there any pressure bias front to rear?

 

[txyaloo]

I did the swap over the weekend but have run into something no one else has mentioned. In the air, everything was good. Tires spun freely. Set the truck down and took it for a test drive only to find the bolts securing the upper ball joint were rubbing on the wheel on each side. I'm running the stock 16s. 2004 tahoe knuckles, CVs, hubs, and 12" brakes.

Anyone have any thoughts on what's going on with the suspension geometry that would cause this?

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[Coveman]

no rub on mine, but i have aftermarket 18” rims with more offset than stock. it looks like either a bigger wheel or more offset would give additional clearance over your stock rims.

perhaps you could either run a wheel spacer or flip the bolts that go thru the uca.

your brake line looks like toast too. you need to bend that hanger, reroute the hose and check for rubbing.