Replacing the Full Hotend Assembly

Sometimes, a simple cleaning or part replacement isn't enough. A catastrophic leak that encases the heater block in plastic, a broken heatbreak, or simply upgrading to a new model may require replacing the entire hotend assembly.

Safety First: Hot Components & Electricity

Before you begin, ensure the printer is completely cool and unplugged from the wall outlet.

Procedure

1. Access the Hotend: First, you need to get clear access to the hotend. On the Stealthburner toolhead, this typically involves removing the front fan shroud and possibly the part cooling fan duct.

2. Disconnect Wiring: Carefully disconnect the wires for the heater cartridge, thermistor, and the hotend cooling fan. If you have a toolhead PCB, unplug them from the board. Otherwise, disconnect them from their respective connectors in the wiring harness.

The toolhead with its front cover removed, showing the hotend assembly, its mounting screws, and wiring connections.

1. Unmount the Old Hotend: Locate the main mounting screws that hold the hotend to the extruder body (e.g., the "groove mount"). Unscrew these and carefully remove the entire hotend assembly from the toolhead.

2. Install the New Hotend: Mount the new hotend assembly, making sure it is fully seated and aligned correctly. Fasten the mounting screws securely.

3. Reconnect Wiring: Neatly connect the wires for the new heater, thermistor, and fan. Ensure the connections are secure and there are no exposed wires that could short.

4. Reassemble Toolhead: Re-attach the toolhead shroud and any other parts you removed.

Calibration is Mandatory After Replacement

After replacing the entire hotend, you must perform the following calibrations before printing: * PID Tune: The new heater will have different properties. A PID tune is essential for stable temperatures. * Z-Offset Calibration: The new hotend's length may be slightly different. You must re-calibrate your Z-offset to get a correct first layer.