I just bought a 1988 F250 4wd 351 f.i. (5.8 in the socialist countries) in excellent condition. I have wanted an F250 4wd for about 30 years. In the course of repairing a pinhole leak in a heater hose I noticed that the bottom ( crank) pulley wobbles, as if it were bent, when the engine is running. The engine is running as smooth as silk ( as smooth as a FORD)... but this wobblin pulley is driving me nuts. I loosened the serp belt and the pulley doesnt seem loose. And I cant find very much tech info online or in my books on this problem. Any ideas???