Finally got around to doing the toothpaste thing to a set of gearboxes, After two hours and 1/2 a bottle of Crud, they freewheel now! Funny thing though, about an hour into it one of the gearboxes froze up and the motor got really hot. I guess I caught it in time, sprayed those cans of air on it to cool it off, applied some more toothpaste changed the polarity to reverse the motors and away she went!

Thanks guys! 1 set down, 11 more to go!

BTW I hooked both motors directly to a 7.2v battery.

I've read that some people hook up the motor to a single D cell battery and let it run to break it in. You also want to seat the brushes in the motor besides breaking in the gear boxes.

I do this with my HO scale model train engines too, really turns a old athearn blue box from a loud growling beast to purring like a kitten. The best toothpaste to use for this I think would be pearl drops its a bit more abrasive then a regular toothpaste

I have a few questions about doing the toothpaste thing. First some say remove the oil and grease--how or what do I use to clean it before putting on the toothpaste? Second what do I use to clean the gears with toothpaste? And third do you run it forward for two hours and then reverse polarity and run again for two hours?
Thanks!

Don't forget a light coat of lithium grease. It'll cut the noise in half. I can now hear my speaker over my gears

I didn't clean the grease and oil off, just poured the toothpaste on. I made some paper sheds to cover the motors to keep the flying toothpaste from messing up my table. Use the same thing you clean your teeth with, water. I used some Dawn dish soap too. I picked a D-cell battery at first, I guess it was dead as it didn't turn the motor over so I grabbed a battery pack and hooked it up. The reason they ran for two hours was because I was in the North Atlantic in my U-boat hunting British convoys! I did reverse one gearbox for 30 minutes or so.

Perry, I'm partial to Penn Reel Lube myself.

I'm a huge fan of standard Crest, the original paste. My trannys seized after 20 minutes, and i found i needed to add water to keep the paste for seizing with the heat.

They work great now!

James, I knew you'd have it covered

I just edited this 2 hours later. I think that's actually a subliminal pun.

I ran my Tiger 1 gearboxes in yesterday straight from the battery. Did them with fine lapping paste for about an hour. Put everything back in with some Triflon, Teflon grease and fitted a grease shield to protect the circuit boards from any flying grease that may come adrift. Turned on and everything sounded great except the motors run backwards

No idea what has happened. Colour for colour the connections have been put back in the correct way.
Just thought I'd ask if anyone has come across this before?

The simple fix is just to swap polarity on the motors and swap the connections round left to right so the steering is right but I would like to figure out whats happened first.

Richard is totally right. When you want to run-in a brushed electric motor, the first and very important thing to do is to adapt the brushes to the collector. Achieving a good aadptation is better made with low currents, for 380 motors the thumb rule is running it with a single AA cell (at these low currents you don't need high discharge ratings) of between 1200-2500 mAh in one direction and another full cell in reverse. in aeromodelling we attach a cheap prop direct to the motor shaft in order to adequately ventilate avoiding the slightest increase in motor temp and mounting the motor to a simple motor mount, sometimes even a vise. Wiring can be made with crocodile clips, again, low amperages permits.
Hope it helps

After turning a gearbox for two hours are they broken in or broken? Meaning will they not perform efficiently now? I've never broken in any motor, didn't know you had to.

Hi Swathdiver
Running-in electric motors is not strictly necessary due to the progressive brushes adaptation with use. In electric flight we do it in order to obtain max. performances from our motors from the very first moment, it's imperative....fortunately for us, brushless motors and LiPo batteries have made e-flight much more easy.
In our tanks is more probable that we burn our boards before our motors break.... It was just a suggestion to enhance performances, but repeat, not stricitly necessary. When runnning static under heavy loads as in your gearboxes running-in process, the sparks between brushes and collector tend to be stronger than those that appear in well runned brushes. These sparks can slightly damage the motor's collector, but nothing really harmful, don't be worried , that's the reason low voltages and no loads are recommended for breaking-in of e-motors (excuse me if I merge the terms running-in and breaking-in, but I'm unsure about which is the correct one)
Cheers
Jose