Oboy 1 1/4 Ton Replace Seals- help

[sakols]

Hi, My Heinwerner Oboy 1 1/4 ton floor jack has started leaking at the end of the main cylinder and is weeping past the pressure relief screw, next to the pump cylinder. I have found seal replacment kits, but would love to find a serivce manual or guidance so I do this right. Can anybody point me to some resources? I think on the pump cylinder there is a sleave that should not be touched. I have no idea how to adjust anything on this jack. can the slotted brass ring on the end of the cylinder be loosented by using a hammer and drift? Any tips or guidance would be appreciated. Thanks -dan