This could be a heat issue. How hot do the hyd. lines & swivel get during operation? If they're hot to the touch, a jump up to next size hyd line may be in order. I've had this issue before with internal hose routing with a paper roll clamp. Unit kept blowing hyd. lines. Found that temp of hoses was too hot- over time weakening the hoses. Stepping up to the next size hose solved the issue.