RC Tank Warfare community hobby forum

The standard Heng Long metal gearboxes can be very noisy and sometimes prone to stripping a gear, this is a brief HOWTO improve them by shimming and bedding them in with grinding paste.

First off remove your gearboxes from your tank - see other posts on opening up and removing tracks / drive sprockets.
Undo the screws holding them down (usually 3) and remove from tank hull after unplugging the motors.
Remove the motors from the gearboxes by removing two screws in the end of each motor by putting a long thin pozi or cross head screwdriver through the holes in the opposite side of the gearbox. NB If you have older boards with soldered motor connections you may need to do this before you can remove the gearbox from the tank.
You should now have a pair of gearboxes like this To undo the gearboxes you need to remove two screws on the bottom and two screws into the braces on one side Screws removed And separate the side from the gears As you can see the gears are touching each other due to the amount of play in the gearbox Take the gears out of the bearings ready for shimming Place 4mm brass washers on the shafts on alternate ends to shim the gears And re-assemble into the gearbox bearings Replace the gearbox side and re-insert the screws - if the gears bind it may be necessary to add washers to the braces, I use 3mm brass washers just because I have them available. You can now see there is good clearance between the gears with the washers on alternate sides. Now its a matter of using grinding paste or other mild abrasive (toothpaste has been used) to smooth the gear teeth where they mesh, put small amounts of paste on the gears and attach a drill to the output shaft, run the drill alternately forwards and backwards for about 10 minutes which should be enough to smooth the gears where they mesh, once complete, strip down, clean off the grinding paste (I wash with paraffin) and reassemble with your chosen grease for lubrication.
Hope this is helpful.

Great write up Jonger

Excellent work.

I liked the idea of using grinding paste but was put off by the fear of not getting it clean afterwards, but this method solves that just fine.

thanks for the instructions......just wish i read this before installing left side gears(thats what i get for not checking here)

awesome post there jonger
very helpful, thanks
lister

Nice one Jonger, I have a lot of nitro clutch shims which are 4mm
Cheers Russell

Excuse the bump jonger .........

A tip this good needs a booster for the newer Guy's n Girls


.

This is a genius mod! It works and it's cheap. They don't come any better then ideas like this.

One mod thought I would run in the gears BEFORE taking them apart to add the washers again..Then you only have to take it apart once.