You might have to lap your brake pads a bit if they're new to get a good bite into the rotor. You also may have an air pocket in your break line.
Did you make sure and bleed your calipers real good after you did your break work? Usually -- air in the brake lines will give you a Mushy break feeling, but sometimes it can be a higher resistance feeling without actually gripping.
You also did reset your calipers by pumping the breaks a few times after your work to get the right rotor/pad width right?
Rael.
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