Recently a customer called in with a prime mover complaining of vehicle wander. He claimed that on choppy road surfaces the vehicle wandered and darted badly. Although the vehicle was 10 years old it was in generally good condition. An inspection of the steering system failed to reveal the problem.We were looking for worn linkage , a partial seizure in the steering column or king pins.
We road tested the vehicle on a rough stretch of road luckily near by and sure enough the truck did move around. We noticed that we were getting some steer from the drive axles when we applied and released the accelerator.
On returning to the workshop, we inspected the 4 leaf spring rear suspension and found that the springs had worn the slippers badly so that there was about 18mm side movement of the springs.
The correct way to test for this is to find a quite piece of road and providing its safe to do so drive at about 50-60 KPH and apply and release the accelerator looking out for any tendency for the rear to steer the vehicle.
Although in this case the truck has 4 leaf spring rear suspension the same fault will present if there are worn axle torque rods. Its worth noting that you just cant assume the fault must be in the steering system. As this example proves the drive axles will also cause steering problems.
Should you experience steering problems contact your nearest Hydrosteer facility.
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