My 1998 F-250 lost its lift. I was looking under it the other day and noticed the rubber overload bumper and the axle touching. I was wondering last year when I changed the tires why my plow was not as high as it used to be (blamed it on the tire size). I read some things about changing the "keys" but they are expensive. Is there an adjustment with out new keys? Do I need to remove the keys before adjusting or just crank up the torsion at the aft end? Thanks for looking.