Wandering Nightmare

I'm not going to try and follow the electrical engineering route, but remember that "output" becomes "input" on a Ford chassis. If the coach has "body roll" the rolling causes the Swing Axle (Twin-I-Beam) to receive a steering input. The more we can limit roll (sway if you prefer), the less unwanted steering input we get. It seems improbable but the rear spring mountings (shackles and rubber bushings) allow the chassis to wander away from being centered on the axle. Since the steering is solidly mounted to the chassis in front, it doesn't wander in the same way as the rear. Rear wandering causes the coach to try to stray out of its lane. Driver corrects, and staying in lane becomes a seesaw battle. Rear Track Bar (Panhard Rod) fights that by keeping the Axle centered under the Chassis.