E350/E450 Handling Problems are caused by too little + CASTER

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Harvard

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Feb 14, 2011
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Our 2004 E450 28 Foot handled terrible until we added additional + Caster to the front wheels.

The Ford Spec for front end CASTER is:

LH +1.3 to +6.8 Degrees
RH +1.8 to +7.3 Degrees

Our unit was:
LH +3.3 Degrees
RH +3.5 Degrees

We added + 2.0 degrees, so we are now at:
LH +5.3 Degrees
RH +5.5 Degrees.

Alignment problems on the E series follow the 80/20 rule in the sense that TOE and CAMBER is 20% of the story while CASTER is 80% of the story. TOO LITTLE CASTER will amplify any external force many fold to the detriment of stability.

If your unit feels like the steering box needs to be tightened up it is because of TOO LITTLE + CASTER.
If cross winds and wind gusts cause havoc it is because of TOO LITTLE + CASTER.
If you think the tail is wagging the dog it is because of TOO LITTLE + CASTER.
If you are needing to drive it all day and never relax it is because of TOO LITTLE + CASTER.

If your unit drives GREAT, like an SUV, it is because you have a proper amout of + CASTER which I am guestimating to be about +5.0 degrees or more.  (Note: The RH caster is always more then LH (CROSS CASTER = LH - RH))



 

cruzn57

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Oct 13, 2010
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boonies of so calif
I have an 89 E350 its pretty good on the highway, but does wander slightly.
I added 1/8" toe in and it is alot better, my question is, how is caster set?
I believe mine is called twin I beam suspension,  does it require heating and bending?
I agree more caster will be beneficial,  but will increase the steering pressure required,
its worth it either way,
thanks

 

Harvard

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cruzn57 said:
I have an 89 E350 its pretty good on the highway, but does wander slightly.
I added 1/8" toe in and it is alot better, my question is, how is caster set?
I believe mine is called twin I beam suspension,  does it require heating and bending?
I agree more caster will be beneficial,  but will increase the steering pressure required,
its worth it either way,
thanks

Yes, I also have the same suspension, and so does every E350/E450. The top mount of your upper ball joints are shipped from the factory with fixed non adjustable sleeves that need to be replaced.

In my opinion, your best choice in adjustable sleeves are from Ingalls Engineering. They are clearly marked as INGALLS 594. They consist of two concentric sleeves that have 360/24 = 15 degrees indices labeled A through X. In order to set them you need a "cheat" sheet which is on the web as "59400.pdf". These sleeves will allow adjustment of both CAMBER and CASTER up to +/- 2.0 degrees each, in any combination of CASTER or CAMBER. All you need to do is, using the cheat sheet, is take the max adjustable + CASTER change which is +2.0 any you will see a black and white improvement.
 

Harvard

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Feb 14, 2011
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By the way, there are no special tools or technique required to change out the CAMBER/CASTER sleeves. What I mean is there is no heavy duty ball joint work, you just jack up the wheel, remove the wheel, loosen the "horse collar" and the sleeves just pry up as per the instructions in 59400.pdf. Then you just slip in the Ingall 594s. Can't say for sure how corroded the sleeves might be in an older unit, use lots of liquid wrench etc....
 

cruzn57

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boonies of so calif
Thanks

I have a few cold ones sitting here , for your consumption.
since its so simple!  LOL

really- thanks for the tip, I'll get some ordered,
I have a caster/camber gauge I use on the race cars,  I can check it with that.

 

Harvard

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Moose Drool dark ale from Montana is my choice, but then I will drink anything that is greater then 32F (+5.0/-0.0) if you get my drift.
 

cruzn57

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boonies of so calif
I like your thinking!  LOL

I ordered the off set bushings (ingall 59400) from "Amazon"
went out and looked at the front susp. I see what your talking about.
guess I should spray it with WD40.
need to wait for better weather, I'll camp in this weather, but I'm a fair weather
mechanic!
been raining for last few days, snow is at 4000ft level,  were 3300'.
warm coffee, and insulated window,  now thats where I'm at!!
 

Harvard

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Feb 14, 2011
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Sorry, I should not have been so cryptic about my temperature tolerance for a good brew. I really meant to imply CASTER is a one way street having a POSITIVE tolerance BUT do not even think, in this day and age, of ever going for a more negative CASTER.

I would love to tell you the full story BUT to compress dealing with a "truck alignment shop" + 5 months and 1800 terrifying miles without any "light at the end of the tunnel" in 5-10 lines is not possible.

So as a recap,:
In a Wellton AZ campground, on 16th Nov last, (at 250 Foot ASL at about 75 Deg weather)  I pulled my front wheels one at a time and made the big adjustment of adding +2.0 degrees caster to each wheel. On that day, after making the adjustments,  I took the RV for a 10 mile return trip just to make sure the front wheels would not fall off as a result of my playing with something that I knew "little" about.

Our 2004 E450 then sat in the campground bone yard (we stay in a park model) until the 11th Feb when we headed out on a 220 mile trip to Laughlin, NV with a toad. This was to be my first real road test on the adjusted CASTER. By chance it turned out to be a fairly windy day. Well, the difference was a black and white improvement in handling.

We have since made the return trip from Laughlin and I had lots of time to think of just  how I could put this experience into words.

The chosen words are:

"When you drive an RV WITH TOO LITTLE CASTER on a windy day, you are going to be fighting the wind and fighting the RV, combined. When you drive the same RV in the same wind WITH ENOUGH CASTER, the RV is going to fight the wind and all you need to do is manage the situation."

I will look forward to your choice of words when winter has passed and you have had a chance to add creditability or debunk my theories about caster.

By the way, I am very interested in knowing about DIY front end alignment measuring equipment. I can do the TOE and CAMBER but I do not yet have a technique established for measuring the CASTER.
 

donn

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For years Ford E series vehicles have been known as wanderers.  Get it to a good alignment shop, and the problem will go away.
 

Harvard

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donn said:
For years Ford E series vehicles have been known as wanderers.  Get it to a good alignment shop, and the problem will go away.

Yes, but the challenge is to identify a "good alignment shop". That is the hard part! IMHO

I can tell you of one chain outfit in Canada, specifically the "truck alignment bay" in Calgary, AB that does not qualify as a "good alignment shop".

I am going to speculate that the bad alignment shops can run through 6-8 alignments a day on one rack. On the other hand, a "good alignment shop" is going to have a much lesser through put per day.

Which operation is going to look better at head office?

JMO that cost me CDN $167.95, Invoice# 623620743 o dated /10/15/10.

 

cruzn57

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Location
boonies of so calif
this is what we use to set  alignment on race cars,
it takes a little time to get used to it,
http://www.racingplus.com/alignment-tools/longacre/magnetic-c-c-gauge-w-case/1362p10523

for toe settings we use a plate  on outside ea wheel, and measure front and rear.
http://www.racingplus.com/alignment-tools/longacre/toe-plates-set-includes-2-tapes/1362p10556

hope thats some help.
 

Harvard

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OP here... since installing the extra +2.0 degrees of caster I have driven this E450 about 4500 miles, it definitely handles like an SUV. I cannot say enough about the difference in handling.

If you are not a DIY owner I would suggest you purchase a set of INGALLS 594 Camber/Caster sleeves then make an appointment with an alignment shop. Be very specific in your instructions asking them to install these sleeves SET TO 0.0 Degrees CAMBER and +2.0 Degrees CASTER then align the TOE IN to be within TOE spec while accepting the resulting CAMBER and CASTER AS IS!  Trust me, it will be well worth the effort IF you own a wandering E350/E450.
 

Molaker

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Springfield, Mo.
Glad it works for you.  My '99 E450 (31.5') doesn't have the same problem, however.  It handles well with Ford spec'd caster.  It might be interesting to know what the weight ratio is between your front and rear axles.  If the rear is loaded heavily, especially behind the axle, it might tend to make the front end a bit road crazy.
 

Harvard

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Molaker said:
Glad it works for you.  My '99 E450 (31.5') doesn't have the same problem, however.  It handles well with Ford spec'd caster.  It might be interesting to know what the weight ratio is between your front and rear axles.  If the rear is loaded heavily, especially behind the axle, it might tend to make the front end a bit road crazy.

Ford spec for CASTER is about +1.3 to +7.3 degrees and I am at about +5.3 degrees (thats neutral which is about +3.3 degrees + 2.0 degrees from the sleeves = +5.3 degrees) so I am well inside the Ford spec.

My theory is they probably handle badly below about +4.0 degrees which is still inside spec. Lets say there is a grey area between +3.5 to +5.0 where load distribution would add to the confusion. Below +3.5 is no mans land no matter what the weight distribution. IMHO.

Do you know what your caster is set at?

At any rate, I no longer have the handling problem since the caster adjustment and my load distribution habits have not changed from before or after the caster adjustment. For example my front weight on one trip weighed in at 4270# (max 4600#) and the rear 7860# (max 9450#).

Thanks for the input, I hope you had a look at:
http://www.rv.net/forums/index.cfm/fuseaction/thread/tid/24815915/gotomsg/25300144.cfm#25300144

 

Molaker

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I don't know what caster mine is set to, frankly.  I did take it to a truck shop specializing in frame work and alignment (bought new tires and wanted to make sure alignment was good), but I haven't a clue what they set it to.  However, it was not bad even before the alignment.  Right now I'm in a "if it ain't broke, don't fix it" mode as far as handling is concerned.
 

Harvard

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Molaker said:
I don't know what caster mine is set to, frankly.  I did take it to a truck shop specializing in frame work and alignment (bought new tires and wanted to make sure alignment was good), but I haven't a clue what they set it to.  However, it was not bad even before the alignment.  Right now I'm in a "if it ain't broke, don't fix it" mode as far as handling is concerned.

I agree with your mode of operation, believe me I did not go looking for this problem, it came to me with a used 2004 28' E450 that I bought last fall and it was a terror to drive at highway speeds. And yes, I did take it out for a test drive but it was not something a novice would pick up on first trip.
 

Harvard

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As it turns out, it is real easy to estimate the CASTER of any front wheel. To get the CASTER you need to make 2 CAMBER measurements per wheel plus a formula.  I bought a 10 inch Stanley bubble type torpedo level c/w rotateable degree index.  To measure the CAMBER I just place the level vertical on the front circumference of the rim where the ends of the level sit on the rim.

Here is the formula:

K = ( 180 / pi ) * ( ( C1 - C2 ) / ( T1 - T2 ) )

Where:
K is the estimated CASTER
C1 is the +CAMBER when the DS wheel is FULL LEFT or the PS wheel is FULL RIGHT.
C2 is the -CAMBER when the DS wheel is FULL RIGHT or the PS wheel is FULL LEFT.
T1 is the +TURN ANGLE when DS wheel is FULL LEFT or the PS wheel is FULL RIGHT.
T2 is the -TURN ANGLE when DS wheel is FULL RIGHT or the PS wheel is FULL LEFT.
DS is the Drivers Side Wheel
PS is the Passengers Side Wheel

To make things simple, the E350/E450 has a TURN ANGLE of about 25 Degrees at FULL LH or FULL RH. Also, the more level the terrain the better.

For example, This is my E450 sitting on a 1/2 degree side to side slope:
DS FULL LEFT +CAMBER = +4
DS FULL RIGHT -CAMBER = -1
PS FULL RIGHT +CAMBER = +3
PS FULL LEFT -CAMBER = -2

DS K = ( 180 / 3.14 ) * ( ( 4 - (-1) ) / ( 25 - (-25) ) = +5.7 Degrees
PS K = ( 180 / 3.14 ) * ( ( 3 - (-2) ) / ( 25 - (-25) ) = +5.7 Degrees

All we are trying to do here is determine if our CASTER less then 4 degrees or is it greater then 5 degrees to know if we have a vehicle with post factory alignment sleeves or not, the so called "truck alignment".

 

KY-Rver

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Sep 26, 2011
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Help.
I have read about the caster settings and now here is my problem.  My E450 2006 model had slightly less than 1 degree of positive caster.  I have installed a 3-1/2 degree bushing which gives me slightly under 4-1/2 degree positive caster. Handling has much improved, however, still some road wandering. Does anyone know of any bushing that will give me more caster? I would like to get to at least 5-1/2 degrees. Any help would be greatly appreciated.
 
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