Trailer hubs rarely fail, except under extreme conditions. Boat trailers used in salt water would be a good example of such conditions; failing to rinse the hubs with fresh water could lead to corrosion forming around the rear seal or rust formations, weakening the lug studs. The metal dust cap could erode beyond service specifications. In some cases, water intrusion seizes the bearings. In all of these cases, the hubs become useless and must be replaced.

DC circuit breakers are available in a wide variety of sizes, styles and capacities, for marine and automotive purposes. Midrange circuit breakers are available at ratings of 30, 40 and 50 amps. High-amperage circuit breakers are available at ratings of between 50 amps and 150 amps. Circuit breakers cannot be freestanding, and to function they must be installed inside a circuit breaker box. Multi-breaker boxes are familiar as the first user-accessible component on a domestic 120-volt service, and single-breaker boxes manufactured for 12 volt use are similar in appearance and function.

When towing a vehicle behind another, there are a few options. You can leave all four wheels of the towed vehicle on the ground and use a tow bar, but there are limitations on some vehicles as to how far they can be towed without causing damage to the transmission or other components. A better option may be a tow dolly, which is essentially a single-axle trailer that the front wheels of the towed vehicle can be driven onto. For this reason, a tow dolly may be ideal for towing front-wheel drive vehicles, as only the rear wheels of the vehicle will remain in contact with the road.

Sunlight, snow and most weather in general can be damaging to your RV. Protect your motor home or travel trailer by covering the roof with a cover, but forget about using a plastic or canvas tarp; sometimes these do more harm than good. An RV cover is made of a special material that is breathable, yet blocks out water and sunlight. It can be installed in about 15 minutes by either standing on your RV or using a stepladder. Though you can do it by yourself, it is easier if you have someone helping you.

A low-side service port is part of an automobile's air conditioning system. It can be found inside a vehicle's engine compartment on the air conditioner's metal pipes. The port is intended for recharging the Freon levels within the air conditioning system.