Occasionally you may need to take an extruder apart for troubleshooting purposes. This is a simple process that will require no tools other than the 2.5 mm hex wrench you received with your MakerBot Replicator.
- Unload the filament from the extruder that's giving you trouble and move it out of the way. To run the script for unloading filament, go to the LCD panel and select Utilities > Filament Options, then select Unload for the nozzle you wish to unload.
- Switch off the power on the MakerBot Replicator and unplug the power supply.
- Now take a look at the front of the extruder. Unscrew the two bolts at the lower corners of the fan guard using your 2.5 mm hex wrench. As one piece, remove the fan guard, the fan, the heat sink, and the spacers. Keep these pieces assembled and move them out of the way, leaving the fan wire attached.
- Now look at the top of the extruder. There are two bolts on the extruder cap, right up against the extruder cable. Unscrew them both and disconnect the motor cable. You should now be able to pull the stepper motor out of the extruder.
- The extruder is now broken down into its main assemblies. To remove any filament stuck in the thermal barrier tube, turn on the MakerBot Replicator and choose Preheat from the main menu. Once the extruder is heated, use a pair of pliers to pull the filament free.
If your extruder is jammed, you can watch this video to learn how to clear a thermal barrier tube block: