Hi,
My 1991 E350 7.3 Diesel cutaway Born Free RV has steering issues! The beast never has been very keen to stay in a straight line on the road once a bit of speed has been built up. I've fitted a steering damper which did help and tightened up the steering box which helped a bit more but it still tends to take off to the left or right at random which is a bit disconcerting with oncoming traffic. The power steering seems to be much too powerful leaving no feel of the road and no willingness of the truck steering to return to centre and stay there. Am I right in thinking the caster needs to be made more positive and how can I achieve this on this vehicle/what parts would I need?

Thanks for any help,

Bryan

 

You didn't mention that you ever had the alignment checked? To me the issue sounds like you have toe out! That is both wheels are turned outward slightly when the steering wheel is set to go straight. Until you have this checked you can't really determine how to fix it. You should have toe in.

 

Thanks for that, it's going to the garage on Monday for investigation so am looking for pointers from more experienced people to help them out.

Does this vehicle have ball joint steering with the cam in the top joint? Can the camber and caster be altered by turning the cam or do I need to fit a different cam?

Thanks,

Bryan

 

While most Ford truck suspensions are not that adjustable Toe is always adjustable. The steering arms that connect to the steering box and then to the arms on each knuckle have a coupling sleeve that has locking bolts. Loosen them and you can turn the sleeve, sort of like a turn-buckle. This changes the length of the arms, changing the toe settings. Other vehicles have other methods but I have never seen a car/truck that Toe could not be adjusted on.

Your coach is based on the E Van chassis. I have an '88 E250 which is very similar to your coach, just a bit lighter duty then yours.
I have over the years checked my Toe and have never had to adjust it but then this van gets very few miles put on it each year. I only use it to tow my race car and move big stuff.

 

Thanks again, I have the 1991 Ford workshop manual and the Ford motorhome chassis manual but nowhere can I find the toe in measurement for this vehicle in either inches, centimetres or degrees.
I have a cold just now and am a wheelchair user (one leg) so don't fancy getting under at the moment but I believe from the books that
the E350 does not have ball joints but a spindle and that the camber on an Econoline is not adjustable. I have read online that the caster service kit (E5TZ-3K064-A) involves a template and cutting away the bottom of the radius arm and then welding in a cam which gives up to 3 degrees but this should not be done on a post 01/04/1984 as the caster has already been increased after that date.

 

Here's a link to a series of diagrams of the front suspension.
Near the bottom is the steering linkage and it shows the adjusting sleeves for changing the toe.
While I don't know the factory specs for toe A good guess would be 1/16 to 1/8 of an inch toe in. This means the distance between the leading edge of the tire is that distance closer to the opposite side tire then the trailing edge of the tire to the tire on the other side.

An easy way to do a quick check is with the help of one other person get two lengths of a straight piece of metal or wood. I use a square piece of aluminum tubing (1 inch) that you can buy at most any hardware or home improvement store. You will need about 6 ft cut into 2 3ft lengths.
Hold the tube against the sides of the tire sidewall as close to the center of the wheel. The tube should be horizontal and extend past the outer edges of the tire. Using a steel tape, measure the distance between the front tires both in front and behind using the tubes as a more accurate point of reference then the tire itself. Compare the difference. "Toe in" is when the front measurement is less then the rear and is what you want to see. Any measurement giving you "toe out" where the front is greater then the rear is a very good indication that that is your problem.

Ford E-350 Van Suspension & Steering Parts

 

I had this issue after i got new tires and an alignment.
my van felt like a death trap!

It turned out to be the specs they aligned to.

Factory specs have the toe on the right side different from the left to compensate for the engine being shifted slightly to the right.

The solution was to do a standard equal toe in alignment.

It has been much better since

 

I now know I have kingpins and the caster and camber cannot be adjusted but I have found this would it work?

http://www.ebay.com/itm/E5TZ3K064A-Ford-ADJUSTER-KIT-FRT-AXL-E-CASTER-CAM-/390822076800?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item5afecfa180

 

Slightly off-topic but for the best alignment I'd look for a local spring & frame shop that specializes in big trucks; semi's, school buses, etc etc. They're equipped and tend to be knowledgeable about our E-Series vans.

The king pin front suspension are pretty much old hat to them---they'll have the equipment and know-how to properly bend the I-Beams as is the common practice for the best alignment.

Avoid those alignment shops in tire stores, dealerships or those whose focus is on cars. They're more about up-selling raspberry scented Freon, chrome license plate brackets and forever wiper blades, NOT proper alignments!

 

Too much tire pressure will also lead to mishandling. Due to a pressure gauge problem I drove an F150 for several years - cursing it's handling characteristics.

Once I replaced that expensive "quality" gauge with an el-cheapo the problems went away.