1967-1979 F100, F150, F250, and F350 2wd Super Duty Front Axle and Steering Conversion
Installation Instructions
Quick Summary:
-Drilling several 7/16" and 1/2" holes
-Welding required for steering box install
-Engine crossmember cutting and welding for less than 7" of lift
Parts you will need to purchase separately:
Front axle- 2005-16 (2017+ requires different track bar bracket assembly- we have limited experience but willing to work with you- message first)
Front coil springs- 2005-22
Front coil spring isolators- From a 2005+ SD. These go between spring and bucket. See part number 5C3Z-5415-AA
Front radius arms (OEM or aftermarket) 2005-2022
Front Shocks- 2005-16 Super Duty at a size that matches the coils used. Bilstein 24-186674 works great with OEM used SD coils
Steering gear- 2005 to 2007 (36 spline input) Lares 11610 from Rockauto is a good option
Pitman arm- 2005-07 OEM style (drop used with appropriate track bar bracket)
Track bar- 2005-16
DOM Tube- 1.5" OD 1.0" ID DOM tube, such as TU1031 from Summit Racing. A 48" length works well and will be cut to size
Front rubber brake lines- 2005-07 are best, others can be made to work
Steering shaft with 3/4" 36 spline shafts on either end, such as Borgeson 000970
Bump Stops - part no. 19-1311-BL, unless cutting the engine crossmember for clearance. If cutting, you'll want a smaller bump stop, but I don't have a good part number. A 1" +/- bump stop will work well for that application.
Step One: Remove factory components
Securely place the truck on jack stands and remove these parts:
-Front wheels
-Front brake hoses (the rubber portion)
-Front shocks and brackets
-All steering components
-Front beams and springs
-Brake line support bracket on the outside of the frame
Clean the front outer frame rails with an angle grinder and a wire wheel, and spray them with a coat of paint. A thick layer of undercoating may prevent the spring buckets from seating correctly, so this is important.
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Step Two: Install front spring buckets
-Place spring buckets on the frame, and use a C clamp to push them flush against the bottom of the frame
-Start all 7/16" X 1.25" horizontal bolts/nuts before tightening to 40 ft/lbs
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Steering box plate and TBB install:
-Position the TBB on the driver frame rail so it is touching or nearly touching the spring bucket, as pictured below.
-Clamp TBB snug to the frame.
-Drill three horizontal holes through the frame rail using TBB to locate. One 9/16 hole and two 7/16" holes, consistent with TBB holes
-Drill one 7/16 hole that holds the bottom of the TBB to the frame rail
-Get steering plate and spacers. Weld the 7/8" OD 2" long steel spacer and the other steel spacers with a stepped outside diameter to the steering box plate
-Position the steering box plate on the inside of the frame rail by running a 9/16 and 7/16 by 3.5" bolt through the holes drilled from the track bar bracket side. The plate should touch the engine crossmember or be very close
-Tack weld the steering box plate in place, don't fully weld yet
-drill from inside the frame rail with a 9/16" bit, the holes that will correspond with the stepped outside diameter spacers (these are for the steering box)
-drill
Install the 2-hole spacer between the track bar bracket and engine cross member. When using a weld-in piece for the engine crossmember, the 2-hole spacer is not needed
Use 1/2" x 3.5" bolts with washers
This will be a tight fit- what I normally do is use a large Phillips screwdriver to locate one side, and then ream the other side out with a 1/2" drill bit. It is normal to take off about .040" or so, but do not be drilling new holes! If this isn't lining up, don't compensate by drilling- double-check if something is holding it from lining up.
Note that F35C and some F25C applications have a longer engine crossmember that has an extra layer of steel on the forward side. The process is the same, but your crossmember will look different
If you will be using the weld-in crossmember pieces, there is no need for the 2-hole spacer. The weld-in piece basically fills this void and allows you to cut the engine crossmeber to gain clearance at the front of the differential. A little further down under the steering box installation instructions, there is a picture of it installed. Also, under the for sale ad for the weld-in pieces, there are more pictures
After all track bar bolts are started, torque the 1/2" bolts to 75 ft-lBs and the 7/16" bolts to 45 ft-lbs
Above: Have all three bolts and spacers connected to the 05-07 steering box as pictured, then weld the spacers in place. Most non-supercabs have the straight upper frame rail and require cutting this slot in the top frame rail for the large steering box spacer to be welded here.
Below: after welding, install this plate into the front driver frame rail as pictured. The 7/16 X 3.5" bolt that goes through the track bar bracket and the 14 bolt that goes through the spring bucket can now be installed with nuts that temporarily hold the steering plate in place for drilling and later welding.
Do not weld until you have drilled all three holes, test fit the steering box in place, and have also installed all 14mm bolts with nuts to hold the plate while welding.
Even though you have 2 bolts/nuts holding this plate in place, still use a C clamp to secure it
Drill the remaining 2 holes with a 9/16" drill bit
Test fit the steering box and check for clearance issues before welding
Clean the frame in preparation for welding
It is common to have a fuel pump and fuel lines near this area- double check there are no fuel leaks and use a temporary shield barrier, such as pieces of sheet metal or a welding blanket, to prevent sparks from reaching the area with fuel lines.
Have a fire extinguisher handy.
Have someone else there watching for flames and ready to put them out immediately. Seriously, don't burn your truck down!
Weld the steering plate in the frame at the points indicated in green below. It may not be possible to weld every surface of this, as the frame flanges are different sizes. As long as you weld the good majority of it, it will do fine.
This is a supercab plate pictured- others will look a little different, but the same idea.
Step Four: Steering shaft
Bolt the steering plate against the outside of the frame using three 7/16" bolts and nuts. Then, use the plate, combined with the pictured step spacers, as a template to drill the two new holes in the frame. Use a 9/16" drill bit. You'll notice that these steps have some overlap with the track bar bracket installation. Borgeson part no 000970 works great
Step Five: steering drag link
Weld the included tube ends onto the 1.5" DOM tube that you buy separately. Part number TU1031 from Summit Racing works great and is what I have here.
The goal is to have this tube be an overall length of 32" and therefore you will cut the 1.5" DOM tube to a length of 26 7/8" to accomplish this. Please tack-weld for testing before fully welding!
You will want to install jam nuts before installing the drag link. The picture below does not show the jam nuts
Also, the pitman arm nut requires a 46mm socket in case you need to remove or install this.
Step Six: Install radius arm brackets
These radius arm brackets use 5 factory-drilled holes. Most trucks seem to have all 5 of these holes drilled, but only use 2 or 3 holes for the transmission cross member.
Remove the rivets one at a time, and before you move onto the next rivet, install a 1/2" bolt and nut in its place. This lets you drill or pound out the other rivet on the same bracket without removing the small bracket that sits inside the frame.
Also, it's helpful to do one side at a time, start to finish, so that both sides of the transmission crossmember are not loose at the same time.
Support the transmission in the middle of the transmission crossmember. Don't press too hard up against this; it weighs a lot less than an engine.
The drilling template will line up with the holes on the side of the frame. If it only lines up with one or two holes at a time, you likely have right/left mixed up. It is common to need to ream out the holes going through the vertical side of the frame.
Driver side pictured above, passenger side below
Bolts installed through vertical surface of frame:
This require reaming but not drilling new holes
Bolts installed through vertical surface of frame- this requires drilling 3 new 1/2" holes
Install both radius arm brackets with a total of eight 1/2" bolts/nuts/washers per side and torque to 75 ft/lbs
F25C Applications:
On the F25C frames, you don't have the 5 bolt pattern up on the frame; you just have one vertical bolt holding the engine crossmember in place. That 7/16 bolt becomes the locator for the radius arm brackets. Those 7/16 bolts don't seem to be consistently spaced on the frame, so I made that multi-slot hole to allow you to place the radius arm bracket where it needs to go. To make it easier to locate, I made the horizontal holes the same as F25a, both in pattern and in intended location relative to the axle centerline. So use the 11 5/8 measurement shown in the F25a fitment guide to locate that bracket over the multi-slop hole, and see the pictures in the F25a fitment guide to make sure the correct side is forward. I would recommend only drilling one hole per side to begin with, then mock up the radius arms and axle to make sure the front/back location is correct. Here is a link to the fitment guide. You'll be going about 1/4 the way down this page:
https://www.battlebornbrakes.com/f25-fitment
Step Seven: Bump Stops
There are two components to the bump stops- Prothane Bump Stops, part no. 19-1311-BL that connects to the spring buckets and frame, discussed earlier, and then the passenger side axle bump stop extender.
These are important as the differential will contact the engine cross member without.
Use the bump stop extender as a drilling template. Drill a 7/16" hole, and bolt down the extender with the included 7/16 bolt.
Step Eight: Brake Lines
Use common 3/16" brake lines. You will likely need 40" for the driver side and 60" for the passenger. The lines are not included, but are readily available at most parts stores.
For the rubber brake hoses, use 2005 Super Duty rubber brake hoses. They mount to the axle itself, and then the top front of the new spring buckets has 2 holes. Use the 1/4" bolts and nuts to attach the rubber lines here.
Other Tips and Info
Shock Absorbers
The shocks will match the springs. If you are using a 2005 F350 front axle/spring, then get a shock for that same application. A factory spring and Bilstein 24-186674 work great together.
Brake Booster/ Master
Most factory brake systems will not put out enough brake fluid volume to feed the large Super Duty calipers. Your brake pedal will feel squishy and be hitting the floor even when the brakes are properly bled. I recommend upgrading to a Super Duty booster and master at the same time you do this swap. Those systems come with a 1 3/8" bore master that puts out plenty of fluid.
Lift
This kit will have the effect of lifting your 2WD about 7". If you want more, it will accept a Super Duty lift.
Rear Axle
A sterling 10.5 works great and will match your new front axle. I am working on brackets to make this a direct bolt-in conversion with SD lift springs.
Front Driveline
The 2005 SD axle I used for the swap in these pictures accepted a common 1350 U joint. You can either get a conversion U joint to make your original driveline work, or you can get a 1350 yoke for your NP205 transfer case and upgrade to a new, higher quality driveline meant for 1350 joints. 1350's and a new driveline are really the way to go if you have the budget.
Sway bars
I am working on this, but it looks like the best rear sway bar option is a Ford Ranger sway bar, and the front SD sway bar should be able to be fashioned to the highboy frame easily enough. More info to come!
Alignment
Have the alignment shop align the vehicle as if they were aligning the Super Duty donor vehicle, not your old truck
Death Wobble?
Super Duty trucks have been plagued with death wobble issues, and the fix is simple. These parts wear out, and now is a great time to replace them if your donor vehicle had high miles or unknown miles- track bar ball joint, track bar bushing, tie rod ends, and ball joints. Rockauto has good prices. You will get it aligned anyway, so bite the bullet and do it now!
Wheels and Tires
The Super Duty axles are wider, so to keep a factory-like track width, you will want wheels that have a larger backspacing. A minimum of 17" wheel size is required to clear the brakes. I measured the overall tread width on the original Super Duty wheels/tires and compared them to my original highboy axles/wheels and 33" tires, and it was within an inch of the same. The 33" tires are a good amount wider than a skinny factory tire, though. I ended up going with a 17X9 wheel with 5.71" backspacing- the part number is KMC XD82979087918. The tires I used were Yokohama Geolandar LT285/70R17, part number 110133320. These work great with factory height SD springs, right great, look great, and have great traction. With this wheel/tire combo, I gained only 1/2" of overall tire width from an original highboy axles/wheels/285/75r16 tires.