I have a Prusa-Mendel (I believe this is the i2) that was working fine, but for the last three weeks has been printing the leaning tower of Pisa. I noticed my bearings were worn so I replaced the smooth rods and bearings for both X & Y. Then I leveled the frame and hung a plumb line to make sure the Z axis was straight. Then I tightened the Y axis belt a tiny bit.
Nothing helped. Whenever I print anything the object slopes back towards the motor end of the Y axis. I can print a perfect square or circle as long as it's 1mm tall. Anything more than that will be crooked on the Z axis. Any suggestions on what else could be wrong?