RC How To:
Clean & Maintain a Brushless Motor - 2
Step 3 - Clean the Solder Post
The 3 solder tabs on the back of the motor are usually set very close to each other, and it's easy for debris to get stuck between the posts. They can potentially cause a short in the motor and possibly damage.
First, clean out any debris from the post and then take a look at the solder. You want to make sure that the solder is not touching more than one tab at a time. If you see too much solder, heat it with your soldering iron and quickly wipe it away with a wet rag before it cools. A solder sucker (wick) will also work.
Step 4 - Open up the Motor
Before you open anything, make sure you mark the timing if your motor has this option. This way it will be easy to set when you put it back together. You're now ready to open the motor.
The parts disassemble easily and can only go back together one way, so there is nothing to worry about. Make sure to pay close attention to the placement of any small washers that might be on the rotor when you remove it and place them back in the same place when rebuilding. You might also take a few pictures of everything that way you can reference it when putting it back together if needed. Be careful when removing the rotor so you don't damage it and make sure you have a clean spot to put it free of dirt and debris.