My 1968 convertible top has seal leaks at the top of each hydraulic cylinder. I see a snap ring above the seal. Is this seal serviceable? Or is it necessary to buy new/rebuilt cylinders? Aside from the leaks they work fine. Then I find that the outer pivot bolts that retain the cylinders to the male hinge are impossible to get off. The Fisher body manual says that simply unscrewing both bolts will let the cylinder down. I can't get either side outer bolt off without removing the entire male hinge assembly. Am I doing it wrong? If so please wise me up. Also if I need new cylinders what brand is best? I see them going for between $100 and $150 and of course the Fleabay specials 'two-for-$99.99'.