I need help finding seals for my Pneumatic High Pressure Pump (Gas booster pump, air-driven liquid pump)

I need help finding replacement seals for my usun xt25 pneumatic liquid pump, its the dual stage dual acting pneumatic gas booster pump. I know STK and USUN also sell the same pump
http://www.sitec.cn/Product-view-id-1105.html

Also if anyone knows of a good teardown guide that would be cool to cause the one I have is from the chinese company who makes same model and the translation is not great. If no ones has done a video of it yet or at least a pictorial then someone should and if Im gonna be doing it anyway I can but im know other people use these so there most be good documentation somewhere.
Ideally I would love to get a replacement o-rings locally but if there is a whole kit I would go for that.