Front end wobble

[booster]

Originally Posted by GallenH

I don't know if this is relevant with your particular RV. I have a 97 PW on the Dodge 3500 chassis. If an alignment is done with the Dodge 3500 specs it's off from what PW recommends. Their values are different from a Dodge Ram van. They caution you to use their specs. A good alignment shop probably knows this.

Beyond that point, even, is that a GOOD alignment tech will be able to drive the vehicle and come up with the best settings to make it drive the way the owner prefers. Those setting will often be much different than the spec calls for. You have to remember that the spec for a van has to cover a full range of use from empty to full capacity, so they will be a compromise most of the time in normal use. When you have a B conversion, the weight and distribution has very little variation by comparison, so the settings can be dialed in to better match the use with no huge compromises.


Factory specs are often set very wide so they are easy to build and still be in spec, and you can have vehicle that handles horribly that is still within the the limits, or "green" as they now say based on the machines.

[Paga]

Papalee,

Sorry for the delays in getting back to you but it took some time to answer some of the questions I had about your 1991 E250 frontend. The first thing I looked at was whether the 2008 and up complete E350 front axle assembly, with the much larger disc brake rotors and calipers included, using an all brand new conversion takeout from a 2018 or 19, would fit into your van.

One of these would also have ball joints, which makes the caster and camber adjustments possible and fairly easy to do. After I resolved my wandering 92 E250 problem, I went ahead and had this frontend upgrade done in 2016, and did the same alignment correction to the caster on the new front end.

So I a new 2016 E350 frontend with less than 100 miles on it in my 92 E-250, with far superior brakes up front as the icing on the cake. A huge improvement that was frankly inexpensive.

This would have been a wonderful upgrade for yours, at a low cost for the complete setup including professional installation, here in Portland.

Unfortunately the frame rails on the 1980 thru 1991 E-series vans are narrower, and so that rules out this upgrade.

In parallel with that investigation I also looked into what parts were available to add the ability to increae your positive caster given there is no adjustment provision on your kingpin frontend. I found a aftermarket bushing that is installed in the bottom of the radius arms under the axles, an eccentric bushing which then allows the positive caster to then be increased up to 4 degrees.

The good news in this is that if caster is the primary issue with your wandering E-250 there is a solution that is inexpensive.

Have you had any luck getting the alignment readings from your shop ? If not that is something we could do on a level surface with some tools I have. It's not difficult to measure your toe, camber and caster yourself.

If we did that, or a shop did it, at least we'd have a baseline of where the frontend alignment is now. Increasing the positive caster often results in improved forward stability, which means the wheels want to track straight and not wander or follow ruts. The steering wheel will return to center when you let go of it after a turn, which is part of the improved stabilty we really desire.

I have proven all of this to myself without any doubt on my van. I could not believe the improvement I saw, it was the first time I had been able to completely relax driving my van at freeway speeds, passing and being passed, and in wind situations in general. I increased my positive caster using aftermarket adjustable camber/caster bushings I personally installed in my top ball joints in place of the OEM bushings.

So exploring this possibilty may benefit you as well, that of increasing your positive caster.

Here is the post I read when I began searching for solutions to the wandering, like you are. The poster is a fellow named Harvard who had the same problems with his E-450 RV. This is well worth reading if you haven't already:

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

Well, this is a long reply to you, but perhaps it will be of some help. If you'd like we can get together for coffee sometime and talk in person. I'm in SE Portland and I think you are in the metro area as well.

Regards, Paga

[Paga]

This should have read:

So I had a brand new 2016 E350 frontend with less than 100 miles on it in my 92 E-250, with far superior brakes up front as the icing on the cake. A huge improvement that was frankly inexpensive.

Also, regarding the eccentric caster bushings I found that would work on your 1991 E-250's radius arms, it claims to be able to add up to an additional 4 degrees of positive caster beyond what you have now. So if you are at 3 now, you could go to perhaps 7 degrees positive.

I'm running basically 7 degrees positive in my 1992 E250 with the new 2016 E350 frontend installed. When I increased the caster on my original 1992 frontend from 3.5 or so to 5.5 the improvement was dramatic. I used a bushing with even more adjustment in the 2016 frontend to acheive the 7 degrees I run now, with great results.

Paga

[Papalee]

I checked with Courtesy Ford and they had NO record of the numbers, called Les Schwab
and talked to one of their technicians and found out that they have numbers in the machine
But they can adjust as needed. He also said the steering problem could be the tires.
I would like to get together some time soon as I get over this cold.

[dicktill]

Originally Posted by Paga

Papalee,

<snip>

Here is the post I read when I began searching for solutions to the wandering, like you are. The poster is a fellow named Harvard who had the same problems with his E-450 RV. This is well worth reading if you haven't already:

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

<snip>

Regards, Paga

Wouldn't it be nice if this guy Harvard was universally correct that the only way to cure handling/wandering problems is more positive caster? Unfortunately for many folks, loose parts/steering box and/or poor toe/camber setting and/or tire inflation problems can contribute. More caster may help the situation but is in no way a "cure-all" for what ails you, as some of the old elixirs promised. YMMV.

[dicktill]

Originally Posted by dicktill

Wouldn't it be nice if this guy Harvard was universally correct that the only way to cure handling/wandering problems is more positive caster? Unfortunately for many folks, loose parts/steering box and/or poor toe/camber setting and/or tire inflation problems can contribute. More caster may help the situation but is in no way a "cure-all" for what ails you, as some of the old elixirs promised. YMMV.

I should have added to the list above: weight distribution. If you have too much weight in the back, it tends to raise the front. Even if the alignment has been done in this position/configuration/distribution (which of course changes a bit as you use fuel, water, etc.), the (temporary) front end geometry changes (toe/camber/caster) that occur as you encounter wind/ruts/bumps/curves (and these unfortunate changes are a necessary evil with any suspension; if you have insomnia some night, you can Google "bump steer" and "roll steer"), can be different to what they would be if the front end was at the design height (although I doubt this is as serious an issue with the twin I-beam front suspension rather than the much more common double A-frames). Along with this is the issue of having the suspension aligned when relatively unloaded, and then how that changes when the vehicle is then fully loaded (in whatever is your typical traveling arrangement is).

In my opinion, a lot of darting/wandering problems are caused by toe-out, rather than the correct toe-in. A small amount of toe-in is specified so that when the vehicle is traveling, and the necessary "slack"/looseness in the suspension allows things to move slightly (absolutely necessary, otherwise the entire frontend would be frozen), so that the front tires are essentially straight as you drive down the road. What happens with toe-out (or possibly, excessive toe-in) is that as you encounter wind/ruts/bumps/curves, one side of the vehicle is loaded more than the other, and that front tire takes over and steers the vehicle that way, and vice-versa. A good way to tell if the toe setting is wrong is to carefully check the tires. Here is one link to tire-wear-vs.-alignment, but you can Google many others: https://www.knowyourparts.com/techni...ing-tire-wear/ These charts can also help diagnose other alignment problems. Of course, they don't show up two blocks from the alignment shop, so you need probably hundreds of miles to form them, and of course maybe longer to "erase" the old ones, although they may never really go away.

Good luck, Dick

[booster]

All of what Dick has been saying is right on, and the fact that so many individuals and shops immediately point to the same solution for all the problems is very disheartening. Suspension, steering, handling is a dynamic and always changing thing going on and there are lots of parts involved that can cause the issues. It takes experience and thinking to work through the tougher issues as just throwing "cures" on it rarely works.


The cheapest and easiest improvement is often toe setting. As Dick said, toe out can make it like herding cats to drive. You can do it in your own driveway with a tape measure, piece of chalk, a nail, and a jack.


Of the list that Dick had, I would add that cross weight, or wedge as the racers call it, can also be added right with front back weight, although it usually would cause pull rather than wander.


If the van does have the twin I beam setup, they can be aligned, but it ain't easy. It takes a frame shop with a frame pulling rack to do and involves bending the lower control arms. I have seen it done, way back around 1985 and it wasn't pretty. On one pickup the control arm broke, loudly. They welded it back together and continued.


The need to find an old school, truck focused, shop, is very important in stuff like this, as all the newer machines will spit out is numbers and the techs don't have much of a clue what they mean.