Technical Inquiries: March 2003

Towable Vehicles

Q: My wife and I just purchased a 29-foot 1997 Flair motorhome, and now we’re looking for a vehicle with an automatic transmission to tow “four wheels down” behind the motorhome. We want a used vehicle that is towable without the odometer rolling up miles, and one that doesn’t require frequent stops to care for its drivetrain. Is there a list of these types of vehicles available? We just joined FMCA.

Jim Kiefert, F314608
Olympia, Washington

A: The January 2003 issue of Family Motor Coaching magazine contained an article about vehicles that can be towed four wheels down without significant modifications. The article “Towables For 2003” (page 66), was compiled from a survey of manufacturers and contains their recommendations in that regard. It pertains only to 2003-model-year vehicles. The 2002 and the 2001 articles are available to FMCA members on FMCA’s Web site “” www.fmca.com “” in the “For Members Only” area. We also published similar articles about the 2000 model year (March 2000 issue), and the 1999 model year (March 1999 issue) that are not available on the Web site. To obtain a photocopy of any of these articles, please send a self-addressed, stamped, business-size envelope along with your request to: Family Motor Coaching, 8291 Clough Pike, Cincinnati, OH 45244, Attn. Editorial Assistant.

These articles do not address the issue of which vehicles accumulate mileage while being towed. As a rule of thumb, however, vehicles equipped with electronic speedometers/odometers, such as many General Motors cars (Saturn, Chevy, etc.), do not accumulate mileage as they are towed. Mechanical odometers do add mileage. If this is an issue for you, you might wish to contact Remco Manufacturing (800-228-2481) and ask about the speedometer disconnect.

Q: I have owned my 1999 Windsport, built on a Ford V-10 platform, since it was new. For the first time since I bought the motorhome, I experienced a problem with the engine stumbling while I was driving in the rain. (We must have had exceptional weather on all of our other trips.) I remember reading about the details of a fix from Ford in FMC magazine, but do not remember the particulars or in what issue I had seen it.

John Marklewicz, F62523D
Pittsburgh, Pennsylvania

A: The fix you are referring to was titled “Water-Filled Air Filter” and appeared in the Technical Inquiries column of the June 2001 issue of FMC magazine. Apparently, when some Ford models are driven in the rain, water is able to get into the air filter and cause a loss of power or stumbling. The fix described in the answer to that letter was a minor modification to the air cleaner housing that was made available under Ford part number YC3Z-9K635-AA. Contact your dealer for inspection and possible modification.
“” J.B.

Q: My 1995 Safari Sahara has a 35-gallon propane tank and a 2,000-watt Freedom 20 inverter. During extended dry camping, it is difficult to keep the batteries charged due to limitations posed by the size of the propane tank. Propane for the generator can’t be used when there is only a quarter of the tank left. This only leaves about 20 gallons for the generator. I would like to use a lightweight auxiliary gas-powered generator to provide some recharging of my batteries, and to run my ice maker, television, and some lights during extended dry camping. I do not need air conditioning, as I usually dry camp in conditions that don’t require it. I’m considering buying a Honda EU2000 generator to provide the above amenities.

I spoke with another Safari owner about this problem, and he said that he used a Honda EU1000 generator in this situation. I spoke with the inverter manufacturer (Xantrex) about this before taking any action. They advised me that the Honda EU1000 generator would be too small and offered the following concerns. My motorhome uses four house batteries. When shore power or the on-board generator (an Onan 6.3-kilowatt propane-powered unit) is activated, the inverter directs power first to the battery charger. This battery charger uses 600 watts of power; therefore, the first 600 watts is directed to the battery charger.

The inverter remote in my Safari is just an on-off toggle switch; therefore, there is no way to turn off the battery charger function. In addition, the inverter has a power share feature that can be set from 5 to 30 amps (the default setting is 30 amps). So, the battery charger’s function will not be reduced until the power exceeds 30 amps. Xantrex officials recommend reducing the power share to 5 amps if I use a smaller generator. In this way, more power would be directed to the appliances; however, battery charging would be slower. Xantrex officials were of the opinion that since all this power would first be directed to the battery charger, the EU1000 would shut down as soon as it was plugged in.

The only way to turn off the battery charger function and change the power share is to purchase another inverter remote control that allows the user to change this. I would rather not get another remote if I can work around that.

Would a Honda EU2000 generator provide a solution for me without causing any problems to my inverter or motor coach? Do you have any other recommendations that would help?

Jim Dickson, F184930S
Matthews, North Carolina

A: With 600 watts going to battery charging and 450 watts to operate the U-Line ice maker, the 1,000-watt generator (EU1000) would be operating slightly beyond the ragged edge. The 2,000-watt machine (EU2000) would be a much better choice, as I have found that when sizing electrical equipment, it’s advisable to calculate the constant loads and double that number to allow for intermittent loads, loss of efficiency, and de-rating for altitude. For instance, a normally aspirated engine will lose about 4 percent of its power for each 1,000 feet in altitude due to rarefied atmosphere. In Denver, Colorado (elevation 5,280 feet), the generator would operate at 80 percent of its capacity; in Leadville, Colorado (elevation 10,430 feet), that efficiency would drop to only 60 percent.

There is, however, another problem. The ice maker requires that 120-volt current be available 24 hours each day. True, it does have a thermostat that will cycle the compressor off when sufficient temperature is attained, but in warm weather, it will be running more often than not. So, you must rely on the battery power to sustain the ice maker when the generator is not running.

Most campgrounds have quiet hours “” 9:00 p.m. to 7:00 a.m., for instance “” during which time you must rely upon the batteries to run the ice maker with inverter power. Of the 450 watts needed to operate the ice maker, about 120 watts of that is used to drive the harvest cycle. You can raise the bail “” not make ice “” during the night, and reduce the load to 330 watts. But that may not be desirable. This equates to about 28 amps per hour times approximately 10 hours, which equals 280 amp-hours needed to get the machine through the night without the generator running, not considering any loss of efficiency.

With four 12-volt batteries (I’m guessing that they are all rated at 105 amp-hours each), multiply 420 (4 batteries X 105 amp-hours) by 35 percent usable (discharged to 50 percent and recharged to 85 percent) and you arrive at only 147 amp-hours (420 X 0.35) of usable energy between recharges. This is far short of the 280 amp-hours you would need. If your batteries are of larger capacity, recalculate using those numbers. Also, consider that the amp-hour ratings of batteries are for new and/or well-maintained batteries.

This is probably the primary reason that ice makers in RV refrigerators have become so popular, since they need 120-volt power only during that brief two or three minutes of the harvest cycle.
“” B.H.

Q: We have a 40-foot Allegro Bus and pull a Saturn four-door sedan, and we have been told by other RVers that we need a supplemental braking system in some states. Is this true?

Kenny & Jacque Dornhoff, F296622
Minden, Nebraska

A: The January 2003 issue of Family Motor Coaching magazine includes a chart on pages 108 through 112 that lists weights at which the various states and Canadian provinces require supplemental braking. Gathering the information from the states isn’t easy, because you end up with differing opinions. Also, there has been some debate as to whether these laws, many of which were written for “passenger car trailers,” pertain to motorhomes.

State and provincial laws aside, the laws of physics always apply and safety is an issue. In addition, as towing has become more popular in recent years, chassis and motorhome manufacturers have clarified their positions regarding supplemental braking. Here is what the Ford literature says about towing and braking: [The] “towing vehicle’s braking system is rated for operation at GVWR “” NOT GCWR. Separate functional brake systems should be used for safe control of towed vehicles weighing more than 1,500 pounds when loaded.” Other literature has shown the weight that can be towed without supplemental brakes as even lower. The RV industry borrowed some of its weight terms from the trucking industry, and in that industry it is assumed that trailers being towed have independent braking systems.

The July 2001 issue of Family Motor Coaching included an article that described many of the supplemental braking systems on the market today. In addition, the magazine has published articles in the past about RV weights (most recently in April 2000).

If you are interested in obtaining a photocopy of any of these articles, please send a self-addressed, stamped business-size envelope to Family Motor Coaching magazine, 8291 Clough Pike, Cincinnati, OH 45244, attention Editorial Assistant. The “Motorhome Regulations” chart from the January 2003 issue also is available to FMCA members in the “For Members Only” section of www.fmca.com.

The motorhome leaning problem Bob Fisher wrote about in the September 2002 issue of FMC (“Leaning To The Right,” page 26) is the same as we had on our 1995 Winnebago Vectra motorhome. Mr. Fisher’s motorhome is built on a Spartan chassis, while ours is on an Oshkosh chassis (now Freightliner). In any case, the equipment placement is basically the same: generator, LP-gas tank, etc. In addition to what was reported earlier, Mr. Fisher needs to do the following:

1. Verify that all of the leaf springs are in good condition, and that springs with the correct part numbers were used.

2. Verify that both the front and the rear stabilizer bar brackets are in good condition and of the latest type.

3. Mount a new tire winch on the frame cross member between the fuel tank and the fresh water tank (if applicable). This moves the spare tire and wheel off the right-rear corner.

4. Install air bags. I installed an Air Lift kit on the front axle with an automatic height control valve to maintain ride height. The air supply for this system is from the accessory port of the motorhome’s air brake system. With this setup, when I deploy the leveling jacks, the system automatically dumps the air bags and refills them to exactly the same preset air pressure.

5. If necessary, add air bags to the rear axle (pending application).

Note: I installed the air bags at approximately 10,000 miles, and our coach now has 47,000 miles on it. The ride, cornering, and handling are still superb, and the motorhome is still level with no lean. Balance Master tire/wheel balancers were installed on the front and rear to prevent vibration from shaking the suspension to pieces.

Next, I had all four corners of the coach weighed at a rally. With the loaded individual wheel weights known, I unloaded the coach and weighed my load by the piece or box. I then placed all the pieces and boxes back in the basement area in such a manner as to equalize the weight at all four corners. It definitely required a lot of effort, but it worked then and continues to work today.
“” R.H.

Q: We have a problem with our motorhome. It is a 33-1/2-foot 1996 Holiday Rambler Vacationer SE on a 1995 Ford Super Duty chassis with approximately 32,000 miles on it. While driving on the highway, the motorhome started to shake, vibrate, shimmy, and jump until I was able to stop the coach. I thought I had blown a front tire. I inspected the tires and the undercarriage as best I could, and I found nothing loose.

We drove on to our winter base, and stayed there for four months. On the way back home, it did it again. I’d driven about 1,000 miles between shakes.

I contacted Ford Motor Company, but the representative there said to “bring it in and we’ll check it out, but we can’t guarantee anything.” Of course, the inspection would be at our expense.

Ross Browning, F254032
Chariton, Iowa

A: If you want to know what’s causing the vibration, you’re probably going to have to take the coach to a Ford dealer “” or some other motorhome repair facility “” for the inspection. It sounds like your motorhome has some worn suspension and/or steering components, even if you were unable to find any problems during your brief inspection. If you’ve inadvertently overloaded the front axle, even with only 32,000 miles on the coach, the extra weight may have caused accelerated wear to the various components.

When the motorhome is inspected, make sure the technician checks the slip yoke and the slip yoke support in the center of the driveshaft, as well as all U-joints. Have the front brakes checked for a sticking brake caliper. Also, have the rubber bushings on the front suspension spring eyes checked. If they are worn, you might want to consider replacing them with polyurethane bushings.

Before taking your motorhome to the dealership or service facility, load it as you would for a normal trip and take it to a truck scale to be weighed. Weigh it in the following manner: front axle only on the scales, both axles on the scales (total weight), and rear axle only on the scales. You should know these figures anyway to help you determine whether your motorhome is properly loaded and balanced. Plus, if the weights indicate that the motorhome is not overloaded, you can show this to the technician during your discussion.
“” J.B.