The E450 has many suspension and steering parts that wear with age and contribute to poor handling and ride issues. I believe a lot of aftermarket suspension 'improvements' are installed when there is an underlying issue with worn suspension parts or an out of alignment front end.
LDs, fresh from the Mothership have Ford's generic alignment. Most rigs need to be fully loaded and then driven a couple thousand miles before the final alignment. Before alignment, you need to have the rig weighted first and the tires adjusted, using the tire Manufacturer's recommended pressure, for the weight of each axle. This is a great time to make sure neither axle is overloaded. Try to get each wheel weight individually, to make sure the load is evenly split from side to side. Overloading one side can cause handling issues.
There is a tire pressure/weight chart in your LD Owner's Manual.
The springs and other parts need to seat in before aligning if not, this can affect the camber and toe-in settings. Both change as the front ride height changes.
As the rig ages and the springs slowly collapse, the toe-in and steering wheel centering will change and needs to be reset, possibly along with the camber.
Both camber and caster adjustments are made by changing the alignment adjustment bushings. They are not a big deal to change and any decent alignment shop should be very familiar with them.
For our 2003 E450, Ford specifies a caster setting of 4 degrees on the left and 4-1/2 on the right-hand side, plus or minus 2.75 degrees, with a 1/2 degree maximum split or the difference between them.
When new, our LD was Factory set to 3-1/2 degrees on both sides and was prone to wander. I soon reset it to 4-1/2 degrees, reducing the wander significantly.
Several years later, I set it to 5 and 5-1/2 degrees and saw even better results. Maintaining the extra 1/2 degree offset to the passenger side seems to eliminate any pulling to one side or the other.
If, during an alignment, the caster is found to have changed from an earlier alignment, suspect worn ball joints.
Beyond the alignment, there are several rubber bushings that cause handling problems.
Shock bushings, especially on the front shocks very often are blown out. This is particularly an issue on Bilstein or any other aftermarket shock, primarily due to the inaccessibility of the driver's side upper shock bushing. These bushings are often not tightened enough, allowing the bushing to move and wear out. The rear shocks also have the same type of bushing and need to be check periodically for tightness.
Loose top shock bushings, front or rear, can cause very poor handling and sway problems.
Both the front and rear Factory sway bars have rubber bushings that can be badly worn by 50,000 miles. Replacing them with inexpensive polyurethane bushings will remove the play in the worn bushing and will provide a performance upgrade, due to their greater resistance to flexing, compared to the soft Factory rubber bushings.
The Twin-I-Beam suspension has four bushings that allow the two radius arms to move up and down. The rear radius arm bushings are prone to wear in higher mileage E450.
Wheel bearings wear and loosen with miles of use and can cause steering looseness and tracking problems. They should be check regularly for proper tightness and either cleaned and repacked with grease or replaced when the front brakes are serviced.
With higher mileage or poor maintenance, ball joints wear out, allowing uncontrolled movement of the front wheels. This can cause a multitude of ailments including drifting to one side, pulling to one side when braking and overall looseness in the steering.
New LDs, have grease (zerk) fittings installed in both the upper and lower ball joints and lube them every time the engine oil is changed. Doing this allowed our LD's ball joints to survive 112,000 miles before being replaced.
Besides the ball joints, the tie-rod ends and pitman arm can wear as well as the steering box, producing steering looseness.
A good alignment tech should check all of the above items for wear, there is no way to accurately align the suspension with worn suspension parts or loose wheel bearings.
While usually not causing handling problems, the steering stabilizer can wear and allow more action in the steering wheel. Our Factory stabilizer was bad at 50,000 miles, the Monroe HD replacement lasted about 40,000 miles. Our LD now has a Bilstein HD stabilizer, we will see if it stays intact any longer.
Taking care of the possible issues above allows our 2003 to drive and handle as well as it did when new.
With Bilsteins, upgraded polyurethane sway bar bushings and a proper alignment, I have never seen a need for bigger sway bars, steering centering devices or a rear track bar. YMMV
Replacing the front and rear sway bar bushings with the listed polyurethane bushing kits is an inexpensive performance upgrade for even a new LD. On our LD, both the front and rear sway bar bushing were visibly distorted. On the front, if you can see any space around where the sway bar passes through the I-Beams, it's worn.
The rear sway bar bushings are easy to replace, once the LD is lifted high enough to allow access. Unbolt each bracket, one at a time, and replace the bushing before moving on to the next.
The front sway bar requires removing the sway bar so the bushings in the I-Beams can be punched out and replaced. It's a little more complicated and requires two workers or the use of jack stands to hold the front bar in position.
Changing both the front and rear sway bar bushings was a Saturday morning project.
I definitely felt a change in handling and sway control after installing the new bushings, which wasn't surprising considering the stock bushings were worn and replaced with much better polyurethane bushings
Larry Wade