I have just replaced my ADM MC&booster with JDM items and got two copper lines off the MC, along with JDM calipers,disc. and also new rear shoes & wheel cylinders.
i have just bled all four corners. took it around the block and the pedal has nothing for about 2-3cm the goes hard. and the brakes bite.
when you press the brake pedal...you feel/hear the booster whoosh, but its rather soft...then the pedal goes hard. the car pulls up, but i'm not sure how good they are though.
mixing copper lines with steel won't matter will it?

anyone got any ideas?
Ade Mc