Is the front fan on your Makerbot Replicator 2 or 2x broken or malfunctioning? No problem!
You can purchase one directly from Makerbot here for the low price of $6.50 and follow these instructions for a quick and relatively painless fix!
Step 1: Unplug Your Printer
A simple yet very important first step to this process. There should be no reason the printer needs to be plugged in to replace your cooling fan. Remember, safety first!
Step 2: Remove the Two Front Hex Bolts
The two hex bolts located in the front of the extruder assembly on the bottom left and right hand corners of the fan. These bolts are long and travel through; the fan shield, the fan, two plastic spacers, the heat sink, and finally into the extruder motor to hold everything in place. When removing these screws be careful not to lose any of the components. Place them in a container and set them aside for reassembly. Make sure to remember the order of the grill, fan, spacers, and heat sink.
Step 3: Remove Stepper Motor
To remove the stepper motor hold the side of the motor and remove the plug on the top of the stepper motor as shown here. Once you have unplugged the motor, it should easily slide out of place. Set the motor aside in a safe place for later.
Step 4: Remove External (Filament) Fan
Remove the filament fan by removing the two phillips head screws located at the upper left and lower right hand sides of the fan. These screws also secure the plastic vent or "fan duct" attached to the bottom of the fan. Carefully remove the screws and the fan should easily come off. Let the fan dangle down and out of the way.
Step 5: Cut Zip Tie Securing the Wire Encasement to the Extruder Assembly
Using a pair of wire cutters or scissors, carefully snip the plastic zip tie that holds the black mesh wire encasement to the top of the extruder assembly. After you snip the tie, peel open the encasement. There is a pre-made slit in the encasement and it should open easily with no further cutting required. Inside the encasement you will find the fan connection.
Step 6: Unplug the Front Fan
Hold one side of the plug firmly with one hand and use a set of small pliers (preferably needle-nose), pull the other side of the plug until the plug separates.
You can now pull the fan off by pulling the wire our carefully. Set the old fan aside or trash it.
Step 7: Plug in the New Fan
After you remove the old fan, reinsert the new fan wire the same way you removed the old wire by threading it through the opening near the top left of the filament fan. You should be able to use your fingers to attach the new fan connection.
Once connected, organize the wires back into the encasement and using a small zip tie, secure the wire assembly back onto the top of the extruder as it was before. Then attach the outside fan with the two philips head screws making sure the wires are passing through the opening of the top left of the filament fan without being pinched.
Step 8: Reinstall Stepper Motor and Front Fan Assembly
Now that the fan has been plugged in and the rest of the extruder assembly is back in place, you can now reinstall the stepper motor by sliding it back into place and inserting the plug into the top.
The stepper motor should slide easily back into place and will be secured when you reassemble the front fan with the hex bolts as you did in step #2.
Snug the hex two hex bolts slightly more than hand tight. If the hex bolts are too tight you might notice extra vibration or clicking of the fan guard if the bolts are too loose.
Now all you have to do is reload your filament and you are ready to print!
Good luck and Happy Printing!