Your unit has too little + caster....Ford ships these units with about +3.5 degrees of caster which is OK for city driving but you need about +5.5 degrees for highway driving.
Wandering at highway speeds
Reply Post by 2kGeorgieBoy
Re: Wandering at highway speeds
Reply #36 on: March 14, 2018, 09:07:02 PM
Jeff..Although we have a 2000 Georgie Boy 31' Maverick "C" on a Ford E450 chassis, I can fully agree on the caster effects, at least for us. When we got the unit in Jan 2014, the dealer had us take into a truck shop for an alignment. It turned out OK....A trip to Moab shortly there after brought out the problems. I then started reading the threads and comments here about the caster settings....esp., from Harvard. I checked the data from the first alignment and found that it was set at about 3 1/2 degrees positive...about in the middle of Ford's recommended range. Shortly before a cross country trip to Maryland in fall of 2016, I returned to the shop where the first alignment was done. I talked to the service manager and he knew of the problems with the E450's and was happy to increase the caster as I asked. The alignment tech was also familiar with it and ended up with settings close to 5.5 degrees positive. WHAT A DIFFERENCE! The unit tracked straight down the road, passing semis no longer caused a white knuckle hold on the wheel, and overall it was just a lot more enjoyable. It did however increase steering effort a little but not anything to worry about. But, be sure that the shop you go to is willing to "think outside of the box". Our first alignment was "plain vanilla", right in the middle like it was always done. Second time out, they were very willing to increase settings beyond what normally would be done, and still stay with in Ford's guidelines (0-7 degrees, I believe). I realize that our E450 chassis is an entirely different animal than yours, but I was trying to add support to the caster increase thinking and how it helped us......if you go down that road.