Howdo
I've some seals, but as to what exactly they are is anyone's guess, and tbh they are really close in inside diameter.
I would say one is thicker slightly, but I know these to be mini pro trial caliper seals, and checking the documents it lists it as a different parts number for the seal. inside diameter appears to be 25mm, which is the same for C2 and mini trials. I cant see that the seat on those two can be so radically different, and for that matter cant see how the O2 is that much different if its the same sized piston.
0.06 or 0.07 of a mill arent critical sizes here. This isnt microbiology those differences are so tiny that im sure -/+ in manufacture would easily eat them up. Its rubber, not ceramic alloy.
Without looking at all the components, and the caliper sides and piston, and im not in any way denying you're at fault, or even wrong, I just cant see how it would make that great a difference that tiny.
If thats a help :? sorry cant really offer any more assistance