Your Mopar is exhibiting an annoying vibration coming from the front of the vehicle at speeds above about 110km/hour and nothing you do seems to correct the problem. The Pitman Arm, the Idler Arm, the Upper & Lower Ball Joints, the Upper & Lower Control Arm bushes and the Tie Rod ends have been replaced. You have even had the front wheels balanced to within one eighth of an ounce on both the inside and outside rims. You have measured the run-out and the diameter on your front wheels to see whether the results are within specification. The annoying problem persists.

More than likely the source of the fault is a cracked front chassis rail, a not uncommon fault with the Chryslers and Valiants manufactured in Australia during the 60’s and 70’s. As the cracked rail is usually on the Steering Box side of the car, particularly in those vehicles equipped with power steering, the chassis rail will require a close inspection to find the fault. The crack may be difficult to find on a fully assembled vehicle so the best method is to remove the Steering Box from the rail, clean thoroughly with a dirt and grease remover and then inspect the rail surface using a strong light. Badly cracked rails are easy to identify but hairline cracks are not quite as easy to spot.

Chassis Rail repair sections are available from a few specialist Mopar parts suppliers. The repair section should be welded to the rail along its full length and then soaked in fish oil before the Steering Box is remounted. This will cure your problem and that annoying vibration will cease.