RE: RC Tank F.A.Q.
Q: What is the best way to break in the metal gears in my Heng Long tank?
A: Here is the method I use:
1) Remove the gearboxes from the tank. It's not necessary to desolder the motors from the board.
2) Spray strong commercial cleaner/degreaser onto the gears.
3) Use a brush to clean off grease and cleaner.
4) Rinse and dry.
5) Obtain a can of medium grit lapping and grinding compound. If you can't find one, then use a good non-gel, tartar control toothpaste. However, the toothpaste will take longer and won't do as good of a job as the grinding compound.
6) Apply the grinding compound or toothpaste to all gear teeth.
7) Screw a 3mm allen bolt into the drive shaft for the drill chuck to grab onto.
8) Insert the allen bolt/drive shaft into an electric drill and run the drill at low to medium speed. Be sure to wear eye and mouth protection.
9) Grinding compound and metal shavings will spray everywhere, so be prepared. After an hour or so, use a degreaser to clean the gears. Then rinse and dry. Give the drive shaft a quick spin with your fingers. The gears should continue to spin freely and smoothly for at least two seconds. If not, repeat from step #6 above.
10) Repack the gear teeth with grease suitable for gears, such as molybdenum, and reinstall the gearboxes back into the tank.