Kingpins and Unit bearings

paradisePWoffrd

paradisePWoffrd

Recovering Project Junkie
Joined
Nov 5, 2005
Location
Newton, NC
In the interest of tech, I thought I might put some stuff here that I was looking into.

Basically trying to figure out if you could update an older (kingpin) axle to run the newer unit bearings.

From my research, the indexing size for 99-04 SD unit bearings in the same as the older spindles.

I really wanted to try and run the 05+ bearing, for the beef. I know that you can swap the knuckles and go BJ, but many wont want to get rid of the high dollar knuckles, etc.
 
I started with some CAD work, but didn't get much farther than that. Big thanks to Ross @Hudson1 for being willing to 3D print the parts for me to try.

Biggest challenge from what i recall was fitting a stub and brakes. The 99-04 bearings would be easier to use, and could likely work by redrilling the knuckle and using the SD stubs. I havent messed with brakes, but honestly think that would be easy once the rest is solved.

I was running under the assumption of being able to use the stub shaft for the kingpin axle, and using factory length components so that spares are easy/cheaper. The 05+ stub is the one I wanted, but couldnt find the dimensions or drawing of one to try. Also, not sure how much value the 05+ stub is without the 1550 ujoint. I believe it would require machining of the knuckle, making them weaker, and wouldnt leave much options for brakes. If someone can get me the dimensions, or has a shaft they are willing to send me, I would be glad to give it another round.


Here are some pics:

This 1st set was what i ended with, to keep the WMS more narrow, but requires a custom slug or stub also.

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Here is the 1 version, that would didn't need the custom stub/slug: You can see how much longer it is.

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Here is the version for the 99-04:

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Not that most here would find it interesting, but I also drew up an adapter to bolt a 05+ bearing on the end of a 9" or any axle using a Set-20 bearing.




At the end of the day, the adapter would likely cost more to machine than anyone would want to pay. Pricing a blank to cut it from was more than i wanted to spend, before the lathe work. I think someone could make it multiple parts that weld together, for cheaper, I just haven't had the time to investigate. Once I knew the dimensions of the different components, the CAD work wasn't challenging.

Also, if you swap your kingpin axle to slip-on rotors, removing the hub as an assembly becomes almost as easy as a unit bearing.
 
I read it as the orange version was for a 99-04 stub?

Quick Google search says kingpin Ford Stubs are 11.375" and 99-04 stubs are 9.39" so maybe it is feasible.

How thick was your adapter?
Click to expand...

Here is the updated image of the CAD. The 5 bolt splindle pattern of the ford interferes with the UB pattern slightly. The larger holes are there to allow socket clearance for tightening bolts, since the UB and Knuckle are both threaded, although one could possibly be drilled out and have the adapter threaded.

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You can see the thicknesses here. Orange is 99-04 and Blue 05+, both with older Ford stubs.

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When drawing these the dimensions to factor are the mating flanges and their recess and spacing, along with where the stub interacts with the hub. The 05+ spacer is so long because the UB is shorter from rear to spline section. It might be possible to use a 99-04 stub with the 05+ UB and shave ~2" off the thickness.
 
The UB sticks into the knuckle deeper than the KP spindle. I believe that you could use a smaller spacer than i have drawn, to put the 99-04 UB in a KP knuckle, using the 99-04 stub. The big question then would be brakes.

The KP spindle works with the dodge knuckle and counter, and i guess that is an option, but the SD UB are much better. I dont have anything but an assembled KP knuckle here, but I have seen 4 different Ford knuckle designs over the years; KP & BJ thru 99, 99-04 SD, and 05+ SD. The KP & early BJ share the same dimensions other than the top of the knuckle.
 
Was doing some maintenance to the rig and decided to test fit the 3d printed pieces, since I had it apart.

I didnt have the correct bolts/studs so ignore that part, but the dimensions seem to match up well. The slug and cap still need work to finish them out, but honestly that is the part most places would already know.

Would still need to figure out the brakes, but there should be plenty of room to adapt a bracket to work.

20201018_172041-jpg.3110650

20201018_171836-jpg.3110649

20201018_171803-jpg.3110651
 
My initial thoughts were to be able to run 05+ UB up front, to match the ones on the rear axle, and speed up possible trail repairs. But I wanted to not have to re-purchase the axle shafts.

With the cost to machine this adapter, most likely, it would be cheaper to build a 05+ sd60, reusing the gears/lockers.

Could also covert the front to a slip-over style rotor, and not have to deal with loose bearings and grease on the trail again.

For my axle, Ball joint eliminators can also fix some of the desire to run UB up front. Changing axles doesnt require pulling apart the hub, or even the slug/cap if you dont run the outer snap ring.
 
I'm digging this, though I still hate king pins I also don't love tapered roller bearings either. Much prefer the serviceability of a unit bearing.

Have you got any quotes for machining yet? I drew up a SD unit bearing cup a year or so ago and the pricing was dumb due to low qty, want to say $4-600/each.
 
Chris_Keziah said:
I'm digging this, though I still hate king pins I also don't love tapered roller bearings either. Much prefer the serviceability of a unit bearing.

Have you got any quotes for machining yet? I drew up a SD unit bearing cup a year or so ago and the pricing was dumb due to low qty, want to say $4-600/each.
Click to expand...

I havent. Weaver Fab sells weld-on cups for like $350 a pair. I looked and a piece of billet to mill this from, as 1 piece was going to be $500+.

I have thought that it could be made in multiple, weld together pieces for cheaper, but still not sure it is worth the cost. Essentially you would take the Weaver Fab cup, section of tube, and the indexing flange; make them lite press fit together, and weld them out. Could likely be done for under $500 with reasonable quantity. Would still need to figure brakes into that setup.

The WMS of the axle will move out some. I will get some measurements, but I recall it being ~2.5" per side.


I think i mentioned above, but by going to slip on rotors, you can essentially eliminate much of the "grease work" when changing shafts.
 
Chris_Keziah said:
I'm digging this, though I still hate king pins I also don't love tapered roller bearings either. Much prefer the serviceability of a unit bearing.

Have you got any quotes for machining yet? I drew up a SD unit bearing cup a year or so ago and the pricing was dumb due to low qty, want to say $4-600/each.
Click to expand...
Off topic but just curious how or what do you service on a unit bearing?
 
Chris_Keziah said:
Guess my wording could've been better, more so the fact it's much faster to disable to change a shaft or bearing.
Click to expand...
I believe the SD unit bearings can be tightened, as they were. Or I recall one version being able to.
 
99-04 could. 05+ aren't serviceable, but are also huge.
 
Maybe I am missing something here, but by putting this adapter in the middle and pushing the wheel mounting surface outboard instead of stressing the bearings as much you are now stressing the king pins a lot more by placing the load farther away from the king pin axis. You would need deeper backspacing on those wheels to get the load back close to the king pin which now is offset from the middle of the unit bearings, as well as fix the scrub radius so the contact patch of the tire is back under the king pin axis as well.

Other than being able to take it apart relatively quickly I do not see the advantages here?

I had to figure all that out with my portal boxes hanging off the ends of my KP60 so that the tire contact patch was still in line with the KP axis so it would turn reasonably normal and not overstress the KPs. Ended up with 8" of BS on a 10" wheel for the 37s to land with the contact patch almost dead-center of the KP axis.
 
OnlyOneDR said:
Maybe I am missing something here, but by putting this adapter in the middle and pushing the wheel mounting surface outboard instead of stressing the bearings as much you are now stressing the king pins a lot more by placing the load farther away from the king pin axis. You would need deeper backspacing on those wheels to get the load back close to the king pin which now is offset from the middle of the unit bearings, as well as fix the scrub radius so the contact patch of the tire is back under the king pin axis as well.

Other than being able to take it apart relatively quickly I do not see the advantages here?

I had to figure all that out with my portal boxes hanging off the ends of my KP60 so that the tire contact patch was still in line with the KP axis so it would turn reasonably normal and not overstress the KPs. Ended up with 8" of BS on a 10" wheel for the 37s to land with the contact patch almost dead-center of the KP axis.
Click to expand...
You are correct. But its really no worse than running a 3" spacer on the axle, and less force than a dually axle.

I was looking into it so that I could run 05+ bearings all around, to help simplify things plus cleaner fixes. In the end, it's not really worth it, IMO.
 
So could you convert the steering knuckle from studs to through bolts like other unit bearings knuckles? That way you could shorted OAL of the adaptor and remove the lip. Removing the lip on the adaptor would make the adaptor cheaper to produce. Just a thought.
 
snipes243 said:
So could you convert the steering knuckle from studs to through bolts like other unit bearings knuckles? That way you could shorted OAL of the adaptor and remove the lip. Removing the lip on the adaptor would make the adaptor cheaper to produce. Just a thought.
Click to expand...

You could. I am not sure how well the cast steel material would be to tap and/or hold the treads. Getting a nut on the backside would be a challenge. Honestly, this adapter isnt really longer than adding 3" wheel spacers on the axle, or 2" BS wheels. It puts it around the same OAW as a 05+ Super60 axle. The adapter could be built cheaper, if made in 3-4 pieces and welded together.

The 05+ unit bearing is much larger that the stock spindle. Not saying it cant happen, but the knuckle would need to be machined to accept the UD directly. Also, the UB is so short, you would have a hard time finding brakes to fit. You would need some spacer there, just to keep the brakes.

99-04 is a different story. I believe you can fit it directly, and redrill the holes. I would have to evaluate it more, but believe it would still need a custom stub.


I have extra Ford stubs and the SD UBs. I need to pic up some cheap SD stubs and other 60 knuckles to do more testing. Currently I have to tear down my rig if I want to look at something else.

I also imagine throwing SD knuckles and UBs on a rockwell axle for a cheap strong setup. Just need to gather those parts to try it out.
 
paradisePWoffrd said:
You could. I am not sure how well the cast steel material would be to tap and/or hold the treads. Getting a nut on the backside would be a challenge. Honestly, this adapter isnt really longer than adding 3" wheel spacers on the axle, or 2" BS wheels. It puts it around the same OAW as a 05+ Super60 axle. The adapter could be built cheaper, if made in 3-4 pieces and welded together.

The 05+ unit bearing is much larger that the stock spindle. Not saying it cant happen, but the knuckle would need to be machined to accept the UD directly. Also, the UB is so short, you would have a hard time finding brakes to fit. You would need some spacer there, just to keep the brakes.

99-04 is a different story. I believe you can fit it directly, and redrill the holes. I would have to evaluate it more, but believe it would still need a custom stub.


I have extra Ford stubs and the SD UBs. I need to pic up some cheap SD stubs and other 60 knuckles to do more testing. Currently I have to tear down my rig if I want to look at something else.

I also imagine throwing SD knuckles and UBs on a rockwell axle for a cheap strong setup. Just need to gather those parts to try it out.
Click to expand...

I was think more about bring the bolts from the ujoint side of the knuckle and threading the adaptor,kinda like a clocking ring. I’m not sure how much room there is to get the bolts through without interfering the ujoint which could be an issue.

Here is my quick sketch of the side view to better describe it.

Example 1 drilling out the unit bearing to bolt it to the adapter. “ not to scale”
0a80d43e88bbd3707468343d5f7c02bb.jpg


Example 2 pocketed bolts through the adaptor and threaded into the unit bearing “not to scale”
deb7ad2a3b673b0c9cf5f44efa37f809.jpg


If these are way off no problem, just thought I might throw some ideas around.


Sent from my iPhone using Tapatalk
 
snipes243 said:
I was think more about bring the bolts from the ujoint side of the knuckle and threading the adaptor,kinda like a clocking ring. I’m not sure how much room there is to get the bolts through without interfering the ujoint which could be an issue.

Here is my quick sketch of the side view to better describe it.

Example 1 drilling out the unit bearing to bolt it to the adapter. “ not to scale”
0a80d43e88bbd3707468343d5f7c02bb.jpg


Example 2 pocketed bolts through the adaptor and threaded into the unit bearing “not to scale”
deb7ad2a3b673b0c9cf5f44efa37f809.jpg


If these are way off no problem, just thought I might throw some ideas around.


Sent from my iPhone using Tapatalk
Click to expand...

I like where your head is at. I have had similar thoughts. When I was "bolting" up the printed part to check, i used a bolt with a nut on the UB side, that went through the threaded holes in the UB. The 05+ UB are threaded too, if you could get a wrench on the back side. You can see the clearance on the picture above.

I used a similar approach with a 99-04 UB. This was to keep the early stub. You can see in the picture how close the bolt patterns are to one another. I believe there are others that have swapped this UB directly. Also believe that some of the "free spin" kits reverse this swap with a custom drilled spindle.

One of my assumptions with all of this, was to avoid custom axle shafts. If someone is buying custom shafts anyway, it changes everything.

99-04 adapter 1.jpg 99-04 adapter 2.jpg 99-04 adapter 3.jpg 99-04 adapter 4.jpg
 
@paradisePWoffrd , Ever made any head way on this idea? Currently running a GM 60 with a Jana 76 conversion and Reid knuckles. Keep breaking 35 spline chromo shafts like twigs. Trying find an affordable way to go 40 spline and haven't found much. From the research I've done, looks like 40 spline unit bearings are far cheaper that 40 spline KP spindles, bearings, and hubs.
 
You could change the spindles and bearings and machine your hubs for the new outer bearings too.
 
71chevytruckguy said:
@paradisePWoffrd , Ever made any head way on this idea? Currently running a GM 60 with a Jana 76 conversion and Reid knuckles. Keep breaking 35 spline chromo shafts like twigs. Trying find an affordable way to go 40 spline and haven't found much. From the research I've done, looks like 40 spline unit bearings are far cheaper that 40 spline KP spindles, bearings, and hubs.
Click to expand...
What are you running that keeps breaking 60's? I'm sure i don't have it, want it, bud butcan't afford to play in your sandbox.
 
GotWood said:
What are you running that keeps breaking 60's? I'm sure i don't have it, want it, bud butcan't afford to play in your sandbox.
Click to expand...
Im sure its a good combination of big weight bouncing up and down with a big tire and some big horsepower...
 
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