If it's just torn boots then Vent the boots to make sure you aren't just blowing the thing from vapor pressure. Cut the clamp on the shaft side (small diameter end) and slip a small brass pipe from a model store or straw from a can of brake cleaner in a pinch. Reclamp with zip ties or the appropriate band clamp. See if that helps them last. Greg hit on the larger scope mechanical wear affecting items but solved similar issues to those you describe this way.