I just bought a used rig w/WESCO trailer & Tie Down Engineering single torsion axle. The torsion cords/bushings are obviously shot because the tires are worn real bad on the inside, no shock action with the torsion arm almost touching the frame. I can see that the camber is way off. Question: Are the rubber torsion cords serviceable/replaceable or do I have to buy a new axle?