Alignment Issues Causing Unstable Steering and Road Wander
Posted: Fri Sep 21, 2012 3:37 pm
Before buying steering stablizers and larger diameter sway bars make sure first that your E350 or E450 chassis has a proper front end alignment. Two alignment adjustments that if set wrong can cause mild to severe steering wander. Those two items are toe in and caster. If toe in is actually set to toe out rather than in, your coach will wander. Toe in should be set to approximately 1/8". The other is caster. The Ford Spec for front end CASTER is:
LH +1.3 to +6.8 Degrees
RH +1.8 to +7.3 Degrees
It is best to have caster set to near the high end of this spec. Having the caster set to around 5 degrees will make a dramatic improvement in steering stability, sensitivity to cross winds and when meeting or passing large trucks.
The Ford E350 and E450 chassis are delivered from the factory with only the toe in adjustable. Camber and caster are fixed and the only way to adjust those two are either to bend the twin I-beam suspension arms or best to have your alignment shop install what are generally called adjustable camber/caster bushings to replace the factory fixed ones. Any light truck alignment shop worth its salt knows about and stocks these adjustable bushings. From my research on other RV forums one source of these bushings is the Ingalls Engineering P/N 59400 a photo of which is provided below.
Have the alignment tech set the toe-in to 1/8" and the caster set to around +5 degrees - about 0.5 degree higher on the right side vs the left side to compensate for the crown of the road.
Then see how your coach handles. The improvement may be rather startling and you may not need to buy a steering stabilizer or heavier duty sway bars.
Any alignment experts on this forum that have better information please post it.
LH +1.3 to +6.8 Degrees
RH +1.8 to +7.3 Degrees
It is best to have caster set to near the high end of this spec. Having the caster set to around 5 degrees will make a dramatic improvement in steering stability, sensitivity to cross winds and when meeting or passing large trucks.
The Ford E350 and E450 chassis are delivered from the factory with only the toe in adjustable. Camber and caster are fixed and the only way to adjust those two are either to bend the twin I-beam suspension arms or best to have your alignment shop install what are generally called adjustable camber/caster bushings to replace the factory fixed ones. Any light truck alignment shop worth its salt knows about and stocks these adjustable bushings. From my research on other RV forums one source of these bushings is the Ingalls Engineering P/N 59400 a photo of which is provided below.
Have the alignment tech set the toe-in to 1/8" and the caster set to around +5 degrees - about 0.5 degree higher on the right side vs the left side to compensate for the crown of the road.
Then see how your coach handles. The improvement may be rather startling and you may not need to buy a steering stabilizer or heavier duty sway bars.
Any alignment experts on this forum that have better information please post it.