Aluminum / XFE NNBS Front Suspension Rebuild

[Scrappycrow]

Do you know or know where I could find the taper specs of the ball joint stud in the aluminum upper control arm and in the steel knuckle? I have some nearly-new aluminum arms from a '21 Sierra I'd like to swap to my '08. It's not worth it to me to get aluminum knuckles, especially since I'd have to get aftermarket drop knuckles. I have no problem with reaming my steel ones.

If the ball joints were the replaceable type, it'd be relatively easy to look up, as those specs are usually listed, but I have never found them for integrated "bespoke" components.

You can determine the taper via taper gauges or measuring:

https://bbs.homeshopmachinist.net/forum/general/71069-newbie-measuring-taper-on-an-automotive-ball-joint

Learn me ball joint angles and reamers.

Learn me ball joint angles and reamers.

grassrootsmotorsports.com

Taper Calculator, You enter any three of Small End Diameter, Large End Diameter, Flute Length, and Taper/Foot and we provide the fourth - Newman Tools

enter any three of Small End Diameter, Large End Diameter, Flute Length, and Taper/Foot and we provide the fourth

www.newmantools.com

If you're going this route, you MUST have a proper setup for doing so. I speak from experience, unfortunately (I damaged a steering arm on my '57 Chevy). To change the taper (not just "clean up" an iffy bore) you'll need to set up a rigid jig and use a drill press that has variable speed down into double-digit RPM, and use machining fluid such as Tap Magic (NOT WD-40 or 3-in-1, etc.). I actually modified my drill press to incorporate a 3-phase motor and VFD (variable-frequency drive) to do this. If this isn't for you, have a machine shop take care of it.

 

[iamdub]

If the ball joints were the replaceable type, it'd be relatively easy to look up, as those specs are usually listed, but I have never found them for integrated "bespoke" components.

You can determine the taper via taper gauges or measuring:

https://bbs.homeshopmachinist.net/forum/general/71069-newbie-measuring-taper-on-an-automotive-ball-joint

Learn me ball joint angles and reamers.

Learn me ball joint angles and reamers.

grassrootsmotorsports.com

Taper Calculator, You enter any three of Small End Diameter, Large End Diameter, Flute Length, and Taper/Foot and we provide the fourth - Newman Tools

enter any three of Small End Diameter, Large End Diameter, Flute Length, and Taper/Foot and we provide the fourth

www.newmantools.com

If you're going this route, you MUST have a proper setup for doing so. I speak from experience, unfortunately (I damaged a steering arm on my '57 Chevy). To change the taper (not just "clean up" an iffy bore) you'll need to set up a rigid jig and use a drill press that has variable speed down into double-digit RPM, and use machining fluid such as Tap Magic (NOT WD-40 or 3-in-1, etc.). I actually modified my drill press to incorporate a 3-phase motor and VFD (variable-frequency drive) to do this. If this isn't for you, have a machine shop take care of it.

I'm usually one to modify or make my own tooling for a one-time-use endeavor. But I don't wanna risk messing up my knuckles. Not for something like this. I'll see what I can get my machine shop to do this for to determine if it's even worth it. Thanks for the excellent info!

 

[Scrappycrow]

You're welcome -- good luck!

 

[petethepug]

I knew after I started the 1st post it was going to be a living update.

I noticed the aluminum steel after I posted the pic but left it. Seems to add a look into how well they buried the XFE concept GM was forced to roll out for staying competitive with Ford’s new aluminum steel metal trucks

I was looking for the photo someone posted of their NNBS truck that was factory with aluminum UCA & LCA but couldn’t find it.

 

[skpyle]

Following. Thanks!

 

[petethepug]

Is this going to be a problem? I got this aluminum hub from Amazon bargain basket that has two blems on the mating surface. Is it a critical or non critical area? It can catch my thumb nail but also easily be buffed smooth. Whatcha think?

 

[iamdub]

Is this going to be a problem? I got this aluminum hub from Amazon bargain basket that has two blems on the mating surface. Is it a critical or non critical area? It can catch my thumb nail but also easily be buffed smooth. Whatcha think?

View attachment 419431

That's a knuckle. The hub bolts to that knuckle. Those blems below the three bolt holes are 100% harmless. Nothing mates to that surface. I'd file down the dings on the mating surface where the hub goes, though. In this pic, the one at the top right halfway between the bolt holes and the ones to the left of the lower right hole. Plus any others that might be out of the picture, at the top.

 

[randeez]

Is this going to be a problem? I got this aluminum hub from Amazon bargain basket that has two blems on the mating surface. Is it a critical or non critical area? It can catch my thumb nail but also easily be buffed smooth. Whatcha think?

View attachment 419431

Nothing mates there, the wheel bearing assembly will line up with the 3 holes and stand off the knuckle

 

[petethepug]

Thanks much for the diagnosis as well as the correct part name. They’re called hubs as well as spindles depending on where you go.

I’ll just remember them as these

 

[Foggy]

I've been following this post on the aluminum vs steel control arms and the
knuckles...
I looked at the parts online .... but holy crap !!!
The aluminum control arms are double to triple the price of my steel OE parts
Would like to get rid of weight for all the right reasons, but I don't know
if the initial investment is worth it $$$