When it comes to modifying vintage trucks, there's no question that upgraded suspensions are at the top of most enthusiasts' wish lists. Let's face it, the phrase "rides like a truck" was basically inspired by pickups from the '40s and '50s, and it wasn't meant as a compliment! So it's no wonder that a more comfortable ride (and a better stance) is something that we're all seeking from our street-cruising haulers.
Now we all know that there are a variety of aftermarket IFS conversion kits available for most classic trucks, and grafting on a later-model IFS subframe is still a popular practice. But let's face it -- there are some folks who can't afford an aftermarket IFS setup and don't have the welding savvy and chassis-building skills to complete a subframe swap. Fortunately, a variety of companies offer components (mono-leaf springs, disc brake kits, etc.) for assembling safe, upgraded front suspensions based on original I-beam axle designs. But up until now, one weak link has remained when rebuilding a beam-axle front end: the kingpin. Original equipment kingpins and brass bushing-equipped spindles from the late-'40s and early-'50s are not exactly what you'd call precision components. Such setups worked fine when new, but are prone to wear and don't do much for handling or steering performance.
That's why we were very happy to see the latest offering from Stainless Steel Brakes Corporation. The company's new Royal King Pin kits for '41-54 Chevy and '37-48 Ford trucks are a great way to bring improved handling and steering response to vintage trucks. These kingpin kits offer several improvements over OEM designs. First, they use needle bearings instead of brass bushings, so lubrication, longevity and steering response are all vastly improved. Furthermore, the kingpins themselves are made of hardened stainless steel. In fact, everything in the kit is either stainless steel or chrome plated for quality and appearance. Best of all, the kingpin kits are designed to fit stock spindles and come complete with an installation tool that makes the job a straightforward affair. And as if that's not enough, SSBC also offers a bolt-on disc brake conversion kit to complement the new kingpin assembly (as well as other straight-axle truck applications).
We recently had the opportunity to watch the installation of a Royal King Pin kit on a '50 Chevy pickup. The straight-axle Chevy was similar to many modernized haulers, as it had already been treated to a crate small block, Turbo 350 and nine-inch rearend. The kingpin kit was a natural addition to the list of modifications, and the accompanying disc brake kit was also a slam dunk. These two modifications alone will make a significant driveability improvement on most vintage trucks, but this particular Chevy was also treated to new Eaton "Rod Ride" leaf springs, a No Limit power steering conversion, and a tilt column for the utmost in bolt-on upgrades.
Follow along and we'll show you the details of the Royal King Pin upgrade. As you'll see, the swap is a fairly simple operation that most enthusiasts could easily tackle in their home garage. Even better than that, it's an upgrade that offers definite handling, steering and maintenance improvements without totally breaking the bank.
Next the original grease zerks will need to come off. There's an upper and lower one on each side. | 
This nut secures both the steering stop and the lock pin for the kingpin. | 
The lock pin needs to come out before the kingpin will. |
With the lock pin removed, the old kingpin can be driven out of the axle bore, allowing you to remove the spindle. | 
The original brass sleeve bushings will have to be driven out of the spindle bores. An appropriate-sized socket can be used as a driver. Once the bushings are out, make sure to thoroughly clean the spindles and check the bores for burrs or gouges. | 
The new needle bearings need to be installed in the lower spindle boss prior to putting the spindle back on the axle. |
The tool provided will help you drive them into place (they should be driven in until each is flush with the spindle casting). Once the new bearings are driven in, it's wise to coat them with a little white grease to keep them lubricated during assembly. | 
As the spindle is slipped back over the axle, note that the thrust bearing has already been set in place on the lower spindle boss. | 
After lining up the bores on the spindle with the one in the axle, the Royal King Pin can be slid through the assembly. The longer end of the kingpin must be installed in the down position, allowing the kingpin notch and the lock pin to align. |
The new lock pin (and old steering stop) can then be installed and secured finger-tight (for now) with a nut and lock washer. | 
The tool provided with the Royal King Pin kit will allow you to press in the top bearings after the kingpin is in place. | 
Once the bearings are pressed in place, an O-ring, stainless cover and grease fitting will cap off the kingpin assembly both top and bottom. |
Note the threaded holes (arrow) in the spindles where the original grease zerks went. These will be sealed with set screws. | 
Here's a finished end on our '50 Chevy axle. Now it's time to break out the lube gun and load the spindles up with grease through the top and bottom fittings on each spindle. You'll also want to grab your torque wrench and tighten the lock pin nuts to between 55 and 65 foot pounds. | 
The Royal King Pin kit is a great way to update your straight-axle truck, and SSBC offers several other upgrade components as well. |
This particular truck was being fitted with SSBC's disc brake conversion kit... | 
...and a modern, dual-chamber master cylinder. | |