E450 Alignment with FOUR Degree Adjustable Bushings

[j-d]

Background: 2002 Front Axle, Radius Arms and Brakes replaced with Same from a new 2012 E450 being converted to 4x4. I did NOT replace the Springs, so they are OEM 4600-lb from 2002. I also did NOT change alignment, rather I installed the 2012 axles with their factory Ford bushings. RV sits and rides nose low. Drives relatively well.
Project: Replace OEM 4600 springs with 5000 SuperCoils to increase axle capacity to 5000 and improve ride height.
Problem: Raising the front of a Twin-I-Beam Suspension does NOT increase the Caster Angle as with a double wishbone design. It actually REDUCES positive Caster. My guess is the 2012 axle was configured for that "default" 3-3.5* and the low ride height increased it to 4* or so. This can be corrected with adjustable Caster/Camber bushings and this is how I plan to do this as part of the Spring Upgrade
Plan:
1. Remove OEM "Camber Bushing" (retains upper ball joint), place on Cardboard and Spray Paint the outline of its footprint, including the Center Hole, noting the Index Tab (which also has a notch for Pinch Bolt, can't fall out if Pinch is only loose, Pinch has to lose its nut and fall clean out before OEM Bushing can escape). Do this for Driver and Passenger Side Bushings.

2. Match an Adjustable Bushing to each of Driver and Passenger paint patterns. Done by orienting the Outer part of the Adjustable to the Pinch Bolt notch AND turning the Inner part within the Outer.

3. Consult the Chart that comes with Adjustable Bushings. De-Code the meaning of the setting made in 2.

4. From position in 3. consult Chart and find a setting that adds the most Caster to setting from 3. without disturbing Camber.

5. Install Adjusted Adjustable Bushing in same orientation as OEM bushings. This should add Caster to the OEM angle.

Oh. Step 000. Pray a LOT first!

I hope I can measure Caster and Camber using an adjustable Level, and decode to Degrees using a formula Harvard sent me. AND that I can adjust the Bushings with Wheels in Place and Tires on the Ground. I bought two sheet "Teflon" cutting boards. Plan is to grease between them, pull up onto the greasy board sandwich, and be able to tweak the position. Like the floating plate on a Rack.

My reading up tells me the Ford Van is set up with very little Caster, +3* being the center of a range that runs up to +7*. The result of +3* is Oversteer. Steering moves off center then moves still farther than wanted. Purpose of all this is add +2* to +4* changing the characteristic to Understeer. Resists going off center by shifting steering axis farther forward of Tire Contact Patch. Distance from where Axis meets Road to where Patch centers on Road is called Trail.

Most OP's have done this job with Ingalls "594" bushings. The equivalent from Specialty is SPC 241810. Both of these can adjust Caster by about 2* to 2-1/4*. I'm interested in bushings that can go to 4* because I don't know what the actual alignment actually is, let alone what it'll be when the ride height increases with the new springs. That's why I'd like to have the 4* adjustment range available. NAPA NCP 264-3950 and probably ACDelco 45K6525 and Moog K80109 are other 4* bushings. I went to NAPA today and used my phone (no copier available) to copy the basic instructions and the degree chart for 2WD Fords. I also looked at a 264-3950 bushing and was surprised to see it's a two-piece bushing. I'd thought it might be three-piece somehow to allow for more adjustment range, but it's not. What I think that means to me, is that it'll be tricky to dial in since each degree of twist is twice the change it would be with a 2* bushing. Here are the two photos.
Your thoughts, please...?

[pauldub]

I set the bushing for max correction on the passenger side and then gave up a little caster to get the needed camber. I didn't need as much correction on the driver side and that side didn't rotate on me. I don't recall if the inner moved relative to the outer or if the whole thing moved. To pin it, I drilled through the two bushings in situ. I pounded in a pin that was a slight interference fit. The pin is in the pinch slot so the difference in the diameter of the pin versus the width of the slot is all that it can now move.

[j-d]

So you set it for Max Caster (was that 4*?) and Zero Camber?

How'd it drive that way?

Did the Inner slip within the Outer? What did you do when you pinned it? I can picture drilling and tapping for a 1/4" screw and then grinding the protruding pieces off...

[pauldub]

The bushing that moved on me was set at the max angle. I did install a new pinch bolt and re-torqued it but it moved again so that's when I decided to pin it in place. Not much rust here in the west to help it not move.

[j-d]

I heard the "shops" don't like adjustables, which is why I've asked here.

Hendersons is emphatic that if the adjustable bushings are installed and torqued properly, they won't come loose in RV service.

Remembered one OP who'd had a problem with them, and pauldub is apparently that OP.

Do you happen to remember what your Settings were on the Bushings, and what Caster/Camber they produced? As I mentioned before, the 4* range interests me because I don't have a way of knowing where the angles will be when I get the springs installed. I don't want to need 3* and only have 2* bushings!

What I'm wondering is if the 4* is more likely to slip like that than the 2*...?

Or just the Luck of the Draw?

The same bushings fit many Fords, maybe even some Dodges. That said, some of the manufacturers don't recommend them for "commercial, RV, box truck, dual wheels, etc. Others specifically say "E450" and there are no E450's with single rear wheels, so that tells me those manufacturers aren't concerned with loosening.

[Harvard]

pauldub wrote:
.... One of them wouldn't stay in place and would slowly change the alignment setting.....

Now that concerns me. My adjustable sleeves are so rusted I cannot imagine how they would ever rotate. How you managed to detect the movement AND execute your fix is impressive.

[pauldub]

You can buy a caster/camber gauge for $150 or so, I have a used one that I bought off eBay for a lot less. I think the best way to measure toe is to scribe a line on each front tire. I jack up the tire and set up a scribe so it will make a nice line while I spin the tire. Measure front and back side of the tire at the same height off the ground and shoot for 1/16 to 1/8" less in front. I have the NAPA bushings that you're looking at. One of them wouldn't stay in place and would slowly change the alignment setting. In the end, I drilled a hole through the bushing where the pinch slot is on the knuckle and then pinned it in place. I'm using plexiglass squares with grease between them for turn plates and they work quite well.

[Harvard]

I cannot remember exactly what I set the toe at but it would be something like 0.25 inch. I did the dastardly deed while staying an RV park in Wellton AZ. Whatever the setting was I can definitely say I have had NO abnormal tire wear. I have been using Michelin Winter Rubber because of Snowbird driving just before New Years.

IMO, all this alignment preciseness is over blown BUT that is only because of 7 years in hindsight.

[j-d]

The Four Degree can be set to Zero. The Two Degree apparently cannot, since those instructions start with removing existing bushings, installing a Zero Degree (from Ingalls, or Specialty, etc.) then checking Alignment on the Rack. Use that info to dial the Two Degree in. For Four Degree, they say to set it to Zero/Zero and to the same "alignment sweep." Makes me wonder if Two Degrees and Four Degrees are determined from the same benchmark/Zero...
Anyhow, our new axle came with offset bushings. That suggests Ford's "Generic Alignment" doesn't use Zero Degree Bushings.
There's a lot to be done on other fronts before I can take on Springs, Bushings, and Alignment.
Harvard, when you set Toe with a Tape Measure, what "difference" are you looking for? I tried to get ours about 3/8" less across the Fronts of the Tire Treads, than the Rear.

[Harvard]

My theory is with the factory 0 degree bushings and a 1 degree nose down chassis the run time caster will be about +3.5 degrees. Just a theory derived from hear say... good luck.

[Harvard]

Where you end up at with +4 is going to depend on the nose up/down angle of your chassis. Worst case my guess is you will have up to +7.5 degrees. Adjust the toe with a tape measure and take it for a ride before you head for the alignment shop.

If you can get LH +6 and RH +6.25 from the alignment shop, go for it.

Finally, tell us all about the experience... :):):)

[j-d]

So you don't seem to have concerns about the 4* vs the 2*. The only OP we read who used 4* was "Taco" in one of your threads on another forum. You requested info from him but we never heard back. I thought you said you'd seen problems with 4*. When I went to NAPA yesterday, I was expecting to see that 4* was going to have a third sleeve in between the Outer and Inner you see on Ingalls and Specialty. If there WAS a third sleeve, I'd be concerned the 4* might come apart in use, more easily than a 2* with two sleeves.
You're one of the OP's I hoped would weigh in on this. If I don't get replies opposing 4* from actual experience, that's how I plan to go.
The axle I installed, from a new E450 that wasn't aligned beyond factory original. has offset (but not adjustable) bushings. You'd think the "generic" alignment would have been with Zero Degree Bushings... Outer sleeve and inner hole concentric...

[Harvard]

I would install them set for +4 Caster and 0 Camber and take it to an alignment shop.

[j-d]

Upgrading Axle and Brakes was a huge improvement. I wanted to do Springs at the same time but they weren't available. The part I missed in this, is the way more ride height means LESS positive Caster on a Ford axle. So in a sense, I'm trapped in the dreaded Mission Creep. This Alignment issue wasn't in the spring upgrade plan.

I hope I can get alignment good enough to not have to use a shop. Cost is one thing, but there are three others:
1. Some shops don't actually DO anything with Caster and Camber on Fords. They just do the Toe.
2. Some shops don't want to work to toward the extreme ends of the spec range. They're used to setting Caster at 3* and think the sky will fall at 5*
3. Many shops don't want to use Adjustable Bushings

[T18skyguy]

All I can say is "wow" your really into it. Are you going to take it to a shop for a final alignment or do you have have a system available? Either way you seem to be doing good work.