All I Learned About a Ford E350/E450 Wheel Alignment

[Ron Dittmer]

CLICK HERE then scroll half way down through the opening post where I later added my experience with a recent wheel alignment. I included many pictures for clarity.

The article is about my 2007 Ford E350 rig that is 23'-8" long. I had changed my front coil springs to softer ones which changed the original wheel alignment.

Much will apply to every E350/E450 based motorhome.

Many people on this forum talk about making sure to have 5 degrees positive caster which falls in-line with nominal specs covered at the very end.

[DonaC]

Ron, how much distance do you have between the I beams and the rubber bumpers above them that limit their travel? I wanted to lower my front end as you have done, but it appears that I wouldn't have much suspension travel left if I did this.

[Ron Dittmer]

Originally Posted by DonaC

Ron, how much distance do you have between the I beams and the rubber bumpers above them that limit their travel? I wanted to lower my front end as you have done, but it appears that I wouldn't have much suspension travel left if I did this.

The short answer is "I don't know".

What I can share are the "mechanics" I used in determining my particular application. I compared my actual front axle weight (loaded on a trip with us sitting in the front seats) to that of the next lower-rated E350 chassis. The weight on my front suspension was well within so I was very comfortable making the change.

As I recall, I had the option to step down two ratings lesser for an even softer ride, but was not comfortable stepping down twice. Sometimes we will have extra passengers so I didn't want to "push" it under those rare conditions.

Each motorhome will have its own "mechanics". It starts with weighing your front axle during a trip with everyone in their normal seated positions.

[sibe]

You went down a road less traveled.... LOL

Optimizing ride and alignment based on your specific vehicle and load requirements..

Some thought, knowledge and good alignment shop can yield good results.

Personally I run a Auto Service since 1984 that is now a full on Collision center, I am a techie geek...also.. I need to know why.. the theory, supported math and practicality.
every day I still learn.....

Things that have been important with twin I Beam since early days in school late 74ish-80's...
Ride Height, vehicle load...
Back in the DAY there was NO cams kits or radius bushing kits etc.. we had a JIG that was purchased that we could tweek/bend the I BEAM to get it dialed..
One of my mentors had his Hunter alignment set up on a Chief S21 frame rack.... He would get a ford van as near perfect as possible....
The Jig would set camber well, on the rack we could twist the jig to get caster.......

the OP here provides some great insight...

Newer E350 and E450 have come a long way, engineering and some changes have made it a tad better but still the design warrants some knowledge to dial in..
Suspension is better with the Rear using modern leaf design that holds up and flexes well at a variable rate. producing a better ride than the old days of 12-14 pack rear springs.. Fronts are better with variable wound sprint that produce a soft ride in the first inch or so of travel then hold weight well.

The RV Class b/ C / Super is on a universal chassis and is a hit/miss at best. especially today with varied floor plans and weight distributions that are skewed by options and even customer add ons and personal loading of their stuff,.
One Model to the next on sane base chassis should have a specific spec by RV Manufacture to Adjust or tweek suspension.. BUT they use a chassis with a beefy design to fit the spread.

SO BLAH BLAH my rant..

Hence the reason so many here, and in RV world seek out After market from springs that add load or make a better ride or rear bags or mods.. then we go to stabilizers / track bars and that rabbit hole....

[DonaC]

In case anyone is curious, this is what mine looks like. About two inches of travel before the I-beam is hitting the bumper. This is back at the frame, so if my geometry isn't wrong, it translates to about three inches of travel at the wheel. And the bumper doesn't completely stop the beam, it compresses, so there is more. Still, I decided not to take any of it away.

[Ron Dittmer]

Originally Posted by DonaC

In case anyone is curious, this is what mine looks like. About two inches of travel before the I-beam is hitting the bumper. This is back at the frame, so if my geometry isn't wrong, it translates to about three inches of travel at the wheel. And the bumper doesn't completely stop the beam, it compresses, so there is more. Still, I decided not to take any of it away.

The next time I have my rig pulled out of the garage, I will measure and report back doing the same as you show with a picture and tape measure.

My E350 front sat exceptionally high before changing front coil springs. This picture was taken before the change. The fancy aftermarket fender flare makes the stance appear lower than it actually was. I wonder what your bump-stop measurement was. I suppose it could be calculated based on your comments. The change to softer front coil springs lowered the front by 1-1/4" measured here.

[sibe]

bumpers wear out too

[THenne1713]

DonaC, I will WARN that MOST RV owners are trying to RAISE as dragging at drives, even gas stations/ Interstate RAMPS, etc.... Dragging REAR due to overhand distance from REAR Axle is worst issue.... I had GEN MUFFLER damage and ENGINE TAILPIPE DAMAGE AND LPG HEAT SHIELD DAMAGE.

[Ron Dittmer]

Originally Posted by THenne1713

DonaC, I will WARN that MOST RV owners are trying to RAISE as dragging at drives, even gas stations/ Interstate RAMPS, etc.... Dragging REAR due to overhand distance from REAR Axle is worst issue.... I had GEN MUFFLER damage and ENGINE TAILPIPE DAMAGE AND LPG HEAT SHIELD DAMAGE.

Hi Terry,

Just to clarify, DonC and I are discussing lowering the front end through the installation of softer front coil springs done primarily to address an excessively rough ride up front. Lowering an excessively high front will "raise" the rear by some amount.