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RV Doctor ColumnRV Doctor #340 Dear RV Doctor, we purchased a used Gulfstream Sun Voyager last year as our introduction into the RV world, and have loved it ever since! I have read in many RV magazines, including RV View, that protecting the tires on these units is critical. Our RV has been in outside storage without covers since December now. When we bring it out in the spring, I would like to "dress" the tires with something to help keep the rubber soft and protect their life some. What is the best thing to buy or use for this? Tom Morton, (West Chester, PA)
Tom, I have had good success over the years using a product called 303 Aerospace Protectant. It used to be called AP 303 in the old days. It's available at any large RV retail store or at any Camping World location. Avoid products containing silicone or any other type of petroleum distillate which can actually dry out the tires making the thinner sidewalls more vulnerable. Ever notice a real "shiny" finish on a recently dressed tire? Yes, it looks nice, but chances are it is not helping to extend the life of that tire or protecting it from ultraviolet sun damage or that nasty ozone that is common in many locales. 303 will not leave the tires shiny, but it is effective. And still consider some tire covers for the next storage period also. You can't beat double protection.
Dear Gary, I have a completely redesigned and restored a 1973, 26-foot Open Road on a Chevy P30 chassis that I take all around the country. Despite its age, I've changed about everything it needed without much difficulty, until now. The gas tank just started to leak so I pulled it out and confirmed that there was in fact a rusted hole along the lower front seam. I have tried the local new parts stores, junk yards, and repair shops but no one has a replacement or wants to touch it. The tank is a simple solid rectangle about 48" x 24"x 15" and should be easily fabricated. Since the tank is already out, I could even supply it to someone as a sample. So my question to you is: How can I get this tank either restored or replaced? Phil Rastocny, (Conifer, CO)
Phil, I feel your pain. It's difficult when one component holds up the whole restoration process. By your dimensions, your fuel container is probably an aftermarket tank installed by the coach manufacturer, and who knows (or can remember) which supplier actually built it. There are many aftermarket fuel tanks available; perhaps you can find one at a supplier called Transfer Flow (www.transferflow.com). They produce many fuel tanks for all kinds of vehicles. They may have one close to the size you need. The engineering, tooling and setup costs for a tank made to your specs is quite expensive. According to the people at Transfer Flow, it would be well over $1100.00 plus shipping. If it were me, I would opt for finding a replacement tank, as close in size to the original that still fits in that location on the chassis. No shop will try a repair (wisely so) because of the liability risk of welding on or near a gasoline container.
Dear RV Doc, I'm new to RVing and am wondering exactly how does a refrigerator run off LP? Eugene Olson, (Washington, DC)
Eugene, of all the appliances found in today's recreation vehicle, the one that is probably the most perplexing to the RVer, is the absorption refrigerator. Understanding the theory of absorption and contemplating why it takes heat in order to make cold can be baffling at best. Then toss in the fact that this is all accomplished with no moving parts and is done silently. Here's a quick primer: Today's RV refrigerator can use three energy sources; 12-volts DC, 120-volts AC, and LP gas. All three energy sources are utilized as heat producers. The 12-volt DC and 120-volt AC electricity are used to power a heater element, while the LP is burned at an open burner. The main component of any RV absorption refrigerator and the one that is most visible on the back of the refrigerator is the cooling core. All cooling units consist of four major component parts: Boiler, condenser, evaporator and absorber. Through these four main components circulate the pressurized and sealed contents of the cooling unit in an endless cycle during the time the refrigerator is turned operating. All cooling units are sealed and, therefore, are not field repairable. Specialized machinery and unique material handling make it mandatory that if a cooling unit is determined to be at fault in a non-working refrigerator, it must be replaced. Inside the cooling unit, added in precise amounts during manufacture are; water, liquid ammonia, hydrogen gas and a compound chemical called sodium chromate. As temperature and pressure act on the contents, they undergo various states of evaporation and condensation, all within the confines of the sealed cooling unit. Because of the caustic nature of liquid ammonia, the sodium chromate is added to protect the insides of the pipes during the refrigeration cycle. When heat is applied to the boiler portion of the cooling unit, the ammonia and water begin to boil. Bubbles of ammonia gas are produced which rise into the percolator tube along with an accumulation of weak ammonia and water. As the ammonia and water solution pass into the tube, the ammonia vapor continues into the water separator. Any water vapor reaching this point is condensed and falls back into the boiler section leaving dry ammonia vapor to pass to the condenser. As air circulates over the condenser fins from the outside, it removes heat from the ammonia vapor inside causing it to condense into a liquid which flows to the low temperature evaporator. The low temperature evaporator portion of the cooling unit is positioned in the wall or shelf of the freezer section of the refrigerator. The evaporator is internally supplied with hydrogen gas which passes across the surface of the incoming ammonia and subsequently causes the vapor pressure to allow the liquid ammonia to evaporate. The evaporation of the ammonia removes heat from the evaporator section through the walls of the freezer, and through the tubing, removing heat from the freezer section of the refrigerator, including any food stored there. The net result is that through the theory of absorption and its principles, the RV refrigerator isn't making cold, but simply removing heat. Cold, therefore, is simply the absence of heat. From the low temperature evaporator, any remaining remnants of liquid ammonia and hydrogen gas are passed lower into the high temperature evaporator which is positioned in the lower section of the refrigerator. This continues to remove and transfer heat from inside the box to the outside, but not as much heat is removed. That's why it is warmer in the food section, or lower portion, than in the upper freezer section. After the ammonia and hydrogen gas pass through the evaporator, the contents flow to the absorber section. Upon entering the upper portion of the absorber, a continuous trickle of weak ammonia solution comes into contact with the mixed ammonia and hydrogen gas which readily absorbs the ammonia from the mixture, freeing the hydrogen gas and allowing it to rise back through the absorber coil and to the evaporator section. The hydrogen gas effectively moves back and forth between the absorber and the evaporator sections. The strong ammonia solution produced in the absorber flows down to the absorber vessel (the large tank-looking container located below the absorber coils) where it is held, mixed with water, and fed into the boiler section, and the process starts all over. Study hard, there might be a test in the next issue!
Dear RV Doctor, I recently graduated to the bigger rigs from towing just a small pop-up camper to a 25-foot Aerolite trailer. I tow this with my 1998 Ford F-150 Extended cab, four wheel drive truck, which came with a heavy duty towing package. This business of tongue weight, gross weights and how it all works together has me thoroughly confuse. I have been towing things for about five years now but never anything so large. I experienced some sway when an oncoming semi passes and it is pretty scary to say the least. Winds seem to do this also. I usually settle down after the first fifty miles or so and seem to anticipate these situations better. I know from reading that tongue weight along with tires, etc., is all very critical but wonder how it all fits together? Should I pack my refrigerator or carry food in the rear of my pickup? Also is it to my advantage to carry more in the rear of my truck instead of inside the trailer? Generally it is just myself on these trips so I am not packing a whole lot of gear. I wish there where a small scale available for sale to check my own tongue weight each time I go out. I do not have a weight distribution hitch nor a sway control. I was told I did not need them by the dealership. It is rather inconvenient to just hop in the truck and trailer and visit my nearest truck stop to weight the tongue prior to each trip. There just has to be a better way! Richard Zawatzke, (Racine, WI)
Richard, obviously, a hitch is the crucial connection between tow vehicle and trailer. Choosing a hitch is determined by weight rating. It is paramount to know exactly what your trailer weights when fully loaded and what the capacity of your tow vehicle is. Then simply choose a hitch that falls within those parameters. Is it that simple? Just about. All good service facilities that install hitches will first ask you about the total weight you will be towing. Next, they will ask you about tongue weight. Tongue weight is that percentage of the total weight that will be placed directly on the hitch assembly. It usually amounts to approximately 12 to 17% of the total weight of your loaded trailer. Any cargo stowed in the tow vehicle behind the rear axle must also be considered and added to the tongue weight when trying to determine the hitch required. It is better to equitably distribute the weight of all cargo inside the trailer rather than add additional weight to the tongue. There are two basic types of hitches: weight carrying and weight distributing. Weight carrying hitches literally carry the weight of the trailer on the hitch and rear axle of the tow vehicle, like yours does now. The maximum weight or limiting factor, for weight carrying hitches is 3,500 pounds. By far the most common type of hitch today is the weight distributing, or load equalizing hitch. Always mounted to the frame, this type of hitch, by its design, distributes the weight to both axles of the tow vehicle. Weight distributing hitches are the preferred method of towing all but the lightest forms of travel trailers. If your trailer, with all cargo, canned goods, personal gear, etc., weighs more than 3,500 pounds you will need a weight distributing hitch. Quite possibly you will also need a sway control. But it is vital that you have the complete towing configuration (truck and trailer) weighed, loaded as if to travel. Aside from having the correct towing equipment, knowing your towing weights will also enable you to properly inflate the tires. Once your typical weights have been determined there is no need to continually measure the tongue weight unless you drastically alter the towing configuration. As long as you remain below the capacity of your truck and have a properly installed weight distributing hitch and sway bar, your towing concerns should be alleviated and you can then enjoy the benefits of towing that RV.
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