Y axis is messed up, calibration hosed  

Y axis is messed up, calibration hosed

I was getting nice, stable prints, PLA/ABS primarily.

During one print, a stray piece of plastic, about 1 cm thick, (unrelated to the print) fell at the back of the Y axis. The impeded travel interfered with the print, and now everything seems to be off.

I've taken the heat bed off and it appears that theres about 2.5 cm or so of lower resistance travel before it binds. This is causing the Y axis calibration to fail.

It happens all along the travel of the Y axis. The rods are smooth and straight.

I can manually move the stepper through the menu, and there is no binding along the path, however, it does think it's about 100mm back of the carriages true position (ie: when I start to adjust the position, what is showing as 0mm is about 100mm in front of the actual rear stop of the carriage)

I upgraded the firmware to 3.2.1, and downgraded to 3.2.0 and finally back to 3.1.1 (what it shipped with), factory reset all data, and attempted to re-run the calibration.

At first, I was able to pass the XYZ check without issue, homing was good. The first layer calibration introduced a lot of Z crashes into the heatbed, subsequent calibration was where the 100mm offset started getting introduced (doing the 9 point mesh leveling, it would start in the middle of the heatbed, and run out of Y axis and crash)

This is when I started winding back the firmware to 3.1.1.

Any ideas on how to address this?