Use engine oil periodically as a fifth wheel lube in cold weather. If parts are very stiff from cold grease or snow, using methyl alcohol or diesel fuel conditioner will loosen the parts up so that they will work quite freely. A small propane torch works well for thawing out relay valves, etc. With the small flame it's easy to watch around airlines. If you are close to hot tap water, pouring hot tap water over the valve will also work. Putting airline antifreeze into supply lines will work also; sometimes I have done all these to get valves to release again. The air line antifreeze helps to prevent freeze ups. Some new trailers advise not to use additives with their filtering systems. If you are in an emergency type situation, I would use the air line antifreeze anyway. Always carry a few spare glad-hands rubbers that were adequate in warm weather should problems arise when weather turns cold.

Using a straight gas line antifreeze of methyl alcohol in air systems dries out gaskets and is very harsh on rubber seals so always have some air line antifreeze with you.

Always carry a spare set of fuel filters and a filter wrench. Carrying a siphon hose with a small squeeze pump on them work well for getting fuel from your tanks into filters when replacing them. If you have the hose long enough, it can also transfer fuel from one fuel tank to the other in case of a frozen cross over line.

Don’t dump large amounts of fuel conditioner in your tanks. Use what is recommended which is usually 1/4 of a container when you fuel up and your tanks are 100 gallons and down better than 1/2. Larger tanks can handle more. Having meltdown on hand works quite well as a rule for fuel gel or freeze up situations. Many cases the meltdown will open up things when poured directly in the fuel tank alone.

If filters are badly gelled up and so are your lines. Pour Meltdown directly into the filters with some fuel and you should be up and running in a short period of time.
 

Carrying some type of container with a squirt cap containing the axle gear oil your equipment uses so that you find an axle housing low on oil you can squirt enough in to keep you going. This very seldom takes more than a few ounces, unless they’re a major leak. In cold weather, driving down the road a few miles will warm up inspection cap and bearing hub, preventing breakage of the plastic cover. These covers can get very brittle over time, so care should taken when removing cap at any time. If you find one that seems brittle have it replaced.

Buying a 50-ft air hose with a supply line glad-hand on one end and an air chuck on the other puts an air supply to all parts of the trailer for pumping up tires, etc.

A 12-volt spotlight usually with a cigarette lighter end on the cord can be rewired to a trailer light socket end. You can easily plug into trailer or tractor sockets to put light at the back of a trailer or wherever necessary.

Purchase a 3/4" airline splice or coupler. This will allow you to remove the airlines from the air dryer and reconnect the lines thus by passing the dryer in case it freezes up. This will get you going when otherwise you would be sitting.