First build ,cat D11

[Cooper]

I started building the hydro parts. I'm making the pistons out of aluminum, it doesn't have any contact anywhere. Do you guys think it would be better to use brass, as I don't want to contaminate the oil, or is that the case when aluminum has contact with something? I'm using brass for the cylinder and stainless for shafts. Honed and polished. The piston has two o-rings , more for guides, and one x-ring for the seal. And the rod seal will consist of a actual seal with o-ring for a wiper, or x-ring.