Mopar Action On-line – Tech Questions
Harlan Schauer, Kabetogama, MN, 1970 Plymouth Duster 340
I have ’70 Plymouth Duster that I did a total resto about tenyears ago and driving since then with no issues. Now my issue is analignment issue. I swapped in manual steering unit and got rid of the powerunit. Now the car pulls very hard to the left. I took it in for an alignmentand everything checks out fine and alignment is dead on. Problem is when Ihit a bump or give her the gas the car will pull hard to the left. After thecar relaxes it is fine again. It’s fine if I drive it like a granny, butthat’s no fun. Brakes are not applied when this is happening. It’s when thefront end lifts up during acceleration or a bump. Torsion bars maybe?
Your symptom is called “bumpsteer”; what’s happening is that the toe ischanging as the suspension moves through its travel. Exactly what’s wrongrequires careful inspection and measurements; the primary points to checkare:
> Center link must be level
> Tie rod sleeve angles must be identical side / side
Since you indicate that the symptoms began when you swapped the chuck, I’dcheck to be sure that the mounting is correct and that the pitman arm isn’tbent.
A good chassis shop can measure and correct this. Explicit details are alsoin the Mopar Performance Chassis manual; that info, in turn, was ripped offfrom a ’60s dealership “Master Tech” service training booklet.
Minimizing bumpteer is one of the keys to having a fun-to-drive Mopar.