Under extreme circumstances your X/Y axis may break. Typically this would only happen in an extreme shipping accident. By X/Y axis, I mean the interconnected set of parts that bridge the X and Y dimension of the printer including both the left and right carriages, the extruder mount, and the bars that make up the X axis.
These parts are considered deeply related, and cannot be easily separated. While the Y axis rods can be easily removed from the carriages, this is not at all true of the X axis rods, which are glued in to place.
Here are the steps to replace your X/Y axis:
Step One: Remove Belts
To replace the X/Y axis assembly, you will need to remove the belts left and right carriages. This should be as simple as removing the two screws which hold each belt in to place.
Step Two: Remove Extruder
You will need to remove the extruder from it's base in order to removing the rest of the assembly. The extruder is held to the base by two screws positioned directly behind the extruder. Remove the entire extruder assembly, and allow it to rest on the printing area.
Step Three: Remove Rods
You will need to remove the rods in order to remove the X/Y assembly. To do this, remove the host clamps in the back of the machine. Be careful not to cut yourself on the sharp edges. You will need to unscrew the clamps before they will release.
Once the clamps are removed, you should be able to pull out the rails.
Once the rails are removed, the X/Y axis should fall free for removal.
Step Four: Replace the X/Y Assembly
Place the new X/Y assembly on the rails.
Replace the host clamps.
Replace the belts
tension the belts.
Replace the extruder assembly.
You have now replaced your X/Y assembly.