Sorry, I went back and re read your first post. You did say that.
YOU MUST bench bleed the master BEFORE install as several have said. Glad you are getting a new one. That will probably fix the issue. Those instructions come with every unit as well as the bench bleed hoses. Follow them exactly. Then install and bleed the system.
if you kept the old MC, they are real easy to rebuild. Yours, being fairly new, just had Chinese rubber seal failure. Kits are cheap.
You may want to study up on silicone brake fluid if you intend to use it. There is much discussion on that. None of it addresses whether unknown Chinese rubber compound can take it or not. Whether it's actually better for unknown Chinese rubber compound or not. If upon taking the old one apart you see the rubber seems "OK" but there is a black fluid coming off of them, it's the brake fluid eating them. Dissolving them. The reason we have trouble from parts we buy for our trucks is that it's all Chinese. The bad batch syndrome happens more often now-a-days. Therefore it looks like a bad vendor. They all buy from the same Chinese broker, So it's not their fault. They can't "switch" to another source. China is improving quality like Japan did. Aftermarket restoration parts are low on the Totem pole. So we live with it and change it out when it goes bad if we can't fix it. Whatever it is.
