RC Car Maintenance
General Cleanliness :
A clean car is a happy car! Not only that, but you will be able to spot problems easier on a clean car than on a dirty car, and also while cleaning it, you can give the car and body a quick look to see if anything is wrong. Use a large natural-hair bristle brush (from a hardware or paint store) to remove dust from the chassis and inside of the body. Use some denatured alcohol or motor spray to clean off tire and asphalt marks from the outside of the body.
Compressed air also works better for cleaning after a good day of racing. But an old sock always does the trick to clean your car sparkling and shining. The soft wool or cotton wipes off the dirt like magic. A small paint brush always cleans unreachable areas and cleans them gently. To wipe of sticky mud under the chassis or on the body of the car using a toothbrush to brush it off also helps. But make sure not to scratch your cars paint with a too hard brush bristles.
A lot of dirt gets accumulated under the chassis and the most to get affected are the screw heads. To get clean and sparkling screw heads under the chassis, spray denatured alcohol on screw heads and then pick the dirt with the help of paper clip. It is an effective way to clean your screw heads that are packed with dirt enough so that your hex driver can have enough meat to grab on. It is recommended to use denatured alcohol as it seems to work better than the simple green or motor cleaner.
Shocks:
Shock absorbers soak up bumps in the track and let the tires maintain constant contact with the racing surface; they also let the tires dip into depressions in the track. If you are a 'backyard basher' or casual hobbyist who doesn't race, you should give your shocks a look over before each time you run the car. If you see any leaks, you need to rebuild your shocks. When rebuilding shocks, you should always use brand new o-rings. Never re-use old o-rings!
Drive Pulleys:
These either turn the belts (on the gear shaft) or the belts turn them (at the diffs). Whether you race indoors or outdoors, you should check the teeth of each pulley before the day's racing begins for any rocks, tire debris, tape, etc., that get stuck in there. Use a hobby knife or a dental pick ('teeth' cleaner, get it?).
Drive Belts:
Provide a way for power to be transferred from the gear shafts to the diff pulleys. The belts should be replaced if you notice any significant wear on them (if you can see threads hanging off the belt, that's significant!). Also, if the belt gets so loose that no amount of tensioning helps, you should replace the belt. Belts are a wear-and-tear item; they must be replaced periodically, just like the belts on a real car!
Bushings:
Used on most rotating parts on sport or budget kits, bushings are better than direct contact between the parts, but not as good as ball bearings. Bushings don't need any maintenance to speak of, just keep them clean and grease them when they are first installed.
Ball Bearings
Used on most rotating parts on pro-level kits, bearings provide a way to eliminate almost all of the resistance that bushings have and serve to make the car quicker overall. For kits with the standard shielded bearings (metal shields on the side), just brush them off every now and then. You may want to put a very light dab of oil and let it soak into the bearing, but for the most part just brushing the dirt off the bearing is fine.
Gear Mesh:
The relationship between the primary drive gear (pinion or clutchbell) and the secondary drive gear (spur gear). A tight gear mesh (the spur cannot 'wiggle' when installed) has too much friction and will cause the motor or engine to work too hard and could melt the spur gear from the friction. A loose gear mesh (the spur can move significantly) will probably cause the pinion gear to strip the spur gear, ruining the spur gear.
To set a proper gear mesh on electric cars, use a small piece of normal notebook or copier paper and put it in between the pinion and spur, and tighten the motor onto the motor mount. Remove the paper, and that is how much gear mesh you should have. For Nitro cars, you can get away with a little bit looser gear mesh than on electric cars because the gear teeth are much larger. Use the same technique described above, but fold the paper once before you put it in between the gears.