You need to keep dirt out of the brush hoods,
because if a brush hangs even just a little, it will arc,
which will wear the comm, and brush fast.
You can buy a comm pen that you install in the brush hood, once you pull the brush out.
Push it in, then spin the shaft by the pinion gear many revolutions, and it will clean up the comm, if you don't have a lathe.
Run cooling fins on the motor,
check for motor heat with a temp gun, the rear motor is going to run hotter.
Once warm-hot stop running the truck, let it cool.
Look at comm often, you can sight thru the brush area and see it.
when it starts to look dark, clean it with the comm pen..
Look at your brushes for wear, and groove marks in them.
If they get scratched- grooved, they will in turn wear the comm down faster.
(not the factory cut grooves that are in some brushes new)
Break the motor in some at a slow speed, before you just full throttle for a whole pack..
Check brush length often, once it wears, to well before it's half of it's original length,(or so,, well don't go too short))
replace it, the shorter it gets, the less spring tension is on it.
The less spring tension, the more chance of brush bounce,
which will lose power, and start arcing, which will make more wear..
You can put a a drop of comm fluid on there but not much, sometimes it helps the brushes set-in, and if you put too much it will just arc the current thru it, and not make power, but make a mess...
Take motor cleaner , and spray out the brush end of the motor, let it dry (blow it out with air)
then re-lube the bearings wiht light oil, a drop or so is all you need of oil...
The softer the brush you buy , they less time it lasts,
the harder the spring you use the less time it lasts,
The ole P94 style brushes I replaced very often, and the would hang using them in dirt.
I use the round style brushes now, like orion revolution or team checkpoint,
and they make awesome power, and last a good while..
The more timing you run, the harder on wear it is,( but I like alot of timing:willy)
Just make sure if you run timing , you need to reverse the way you time the rear motor.
Outerwears makes motor covers now that should work good,
that rear motor in a fast clod on dirt catches lots of debris,
and thats like running your nitro without a air filter.....
I can get , I am sure at 20 li-po packs thru mine before they would need attention...
But I just judge by the looks, and wear, and not time..:tmb
But once you comm gets worn, power, brush bounce, and arcing will just get worse, and worse..
It will change the timing, of the motor, and well needs attention..
Even if you don't have a lathe, you can take the armature out, chuck it in a drill, then take some 400 grit wet sandpaper, wrap it around known flat surface, and lay it against the comm while running the drill, (use a light oil while doing this to keep the paper open)then go to 600- 1,200 grit paper, and cleanout the grooves with a x-acto..
You will see the low spot where the brushes ride, and you can keep going, removing then the high spots.
In a pinch this will let you keep using your stuff..
