RV Clinic October 2015
Max Tire Pressure Versus Reduced Pressure
Q: It’s an old question, but I do need your advice. I just bought four new tires for my trailer: P205/75R14 by MotoMaster, made in China. The dealer inflated them to 35 psi, and the tire sidewall reads, “Max pressure 51 psi.” What would you put in? The trailer weighs 5,000 pounds.
I had Towmax Power King trailer tires that were two years old with lots of sidewall cracks and 1/32 inch of wear. The Towmax dealer would not give any warranty for them, and that’s why I went with passenger-car tires, which I had on all my other trailers with no problems.
Marc Bazin, via email
A: First, we do not recommend you use passenger-car tires on a trailer. Trailer tires (called special trailer or ST) should be considered first because they are designed specifically for the way trailers are used — other tires are not. Failing that, light truck tires (called LT) can be used. That being said, the dealer probably left the pressure lower because he felt the tires had excess weight capacity for your trailer’s weight. Each tire manufacturer supplies a weight and loading/tire pressure chart for each tire it sells, and your tire dealer should be able to supply that chart. If your trailer weighs 5,000 pounds and your tire capacities add up to 8,000 pounds, for example, you can somewhat reduce the inflation pressure to provide a softer ride.
However, if you have not weighed the trailer (individual wheel weights would be ideal) and therefore do not know its true weight, we recommend you use the maximum inflation pressure listed on the tire sidewall to provide the highest load-carrying capacity.
Those MotoMaster tires are very inexpensive, which is a red flag, and I hope they do the job for you. Drop a note later and let us know how they work out. — Jeff Johnston
Q: I purchased a 2013 Coleman 249RB last year at the Camping World here in Las Vegas. I was wondering if there could be a way to move the island entertainment center toward the rear about 6 inches or so. The bed is just a bit too short for me, making for some uncomfortable nights. I don’t think it is a load-bearing wall or anything like that. It seems like only screws attach it to the floor and ceiling. The wiring would have to be adjusted, this I know. I would sacrifice some room aft, but I’m willing.
Gene Johngrass, Las Vegas, Nevada
A: That island entertainment center at the foot of the bed may not be a bearing wall in the same sense as defined in a fixed residence, but it is part of the overall structure of the trailer. A shift in the wiring is likely called for, and it’s important that, if you move it, you have it secured well to the appropriate-size structural floor and ceiling members to maintain the unit’s body strength. You also need to be sure its new position won’t interfere with the slideout room when stowed for travel.
This could be quite a project, so unless you’re really good with this type of remodel, you may want to leave it to a shop with qualified technicians. — J.J.
LED Light Interference
Q: We own a 2010 Forest River Rockwood 8265 ultralight fifth-wheel. We have been replacing the 12-volt DC incandescent lamps with LED lamps to save energy. The problem that occurs is that, when the TV antenna signal is poor and these light fixtures are used, the TV reception is reduced or shut off completely. The same seems to occur with different brands of LED replacement lamps.
I have checked all of the cable connections front to rear that I can access, but there has been no improvement.
Dave Thayer, Auburn, New York
A: Each of those LED lamps contains a small electronic circuit board to regulate the voltage to the bulbs, Dave, and those circuits vary a great deal in complexity, cost and design. They also vary in how much radio frequency (RF) emissions they produce or feed back into the RV’s 12-volt DC system. The more RF produced, the more likely it’s going to cause interference.
At the same time, your TV should have fully shielded cables connecting it to the antenna and signal amplifier, and those should help protect it from stray signals. A low-power channel means that a reduced-strength signal can be subject to more interference by outside sources such as the LED light circuits. First, check the coaxial cables to be sure the shielding hasn’t been damaged and the contacts aren’t corroded. This situation could also be aggravated by a bad ground connection in the power lines to the TV, the amplifier or antenna. Inspect all of your ground-wire connections, including those right at the battery and converter. This is your best bet for tracking down the source of the interference. — J.J.
Stuck Dump Valve
Q: We recently purchased a 2014 Coachmen Brookstone fifth-wheel, and we are the first owners. There are three holding tanks: two gray and one black. We opened the black tank only two or three times before it would not close off totally; the same thing happened with one of the gray tanks. We put lots of water in the black tank before we flush it. We have tried filling the black tank with freshwater at least five times to clear any debris from the valve. What would you suggest we try next?
Don M., Safford, Arizona
A: It seems like your trailer is under warranty, so this is the type of situation your dealer should be able to clear up for you in person. Your trailer isn’t old enough for this to be a corrosion-related problem, and dump valves normally operate smoothly for years before jamming becomes a problem.
A black-tank valve could theoretically become jammed due to some solid obstruction dropped into the tank, but a gray tank, with nothing but liquid waste in it, should not cause the valve to stop closing completely. We don’t have all the specs on your trailer, but if it uses valves controlled by flexible cables, the cables have probably gone out of adjustment. This is a common problem with this type of dump-valve actuating system, as some manufacturers tend to use cable attachments that aren’t especially robust, but it’s a fairly easy problem for the dealer to adjust and set right, once access is created.
Our best advice is to visit your dealer and have them adjust the cables, and you’ll probably find the valves will close completely again. You can also check an RV accessory shop for waste-tank additives that include valve lubricants, and those may likewise help out. — J.J.
Q: I have a 2010 Suburban that I use to tow a 35-foot travel trailer. The GPS on the Suburban works well, but it does not seem to know that I pull a trailer, so it continually routes us through some tight places to save a few feet of travel distance or a few seconds of time. Is there an update to the GPS map/system that would be more sensitive to someone pulling a large trailer? It would seem logical that there would be, since people pull heavy trailers with the large Suburban, and surely they don’t want to go down small roads with 10-foot clearances.
Dick Donovan, Reston, Virginia
A: If you can determine the model number of the GPS (it should be on one of the screens), you can try an online search for an update. It’s often a simple disc that’s relatively cheap. You can also check with a Chevrolet dealer.
A vast percentage of those who use GPS navigation systems are driving solo vehicles, so factory systems aren’t geared toward those who tow trailers. There are a lot of different trailer sizes, so it would be difficult to come up with a one-size-fits-all GPS towing program. Garmin, Magellan and Rand McNally offer GPS devices designed for RVers. All of these devices allow you to program a personal profile and guide accordingly. — J.J.
Awning Edge Slipping
Q: I just noticed that on our A&E slideout awning the edge of the fabric with the sewn-in rope is coming loose. This problem just started, and I would like to know the best way to get the cord back in the tube. We’ve had the camper since 2005. I tried unwinding the tube but could not get it completely unwound. Any help will be greatly appreciated.
Dave Meekins, Blythewood, South Carolina
A: It seems like the polycord is sliding out of the fabric. During manufacturing, the polycord is sewn into the fabric. You’ll need a partner to help you unroll the fabric from the roller tube. Use a cotter pin in one of the holes in the head casting, through the main shaft, to immobilize the spring. At this point, you should be able to slide the polycord back in place. Install a screw through the edge of the fabric into the roller tube to prevent future sliding. Do not use a long screw that may interfere with the spring assembly. Pull the cotter pin, and the fabric should roll back. There’s lots of tension on the spring, so both people must hold on tightly, and it’s wise to wear protective googles. If you’re not experienced with this type of repair, seek professional assistance. — J.J.
Towing a Jeep
Q: I recently purchased a tow dolly to tow my 1986 Jeep CJ7. It is a 258 inline-six engine with a five-speed tranny. I need to know the procedure to tow. Do I have the key on to keep the steering wheel unlocked? Can you advise me on how to tow this vehicle?
Rebecca Risher, Charleston, South Carolina
A: When you are towing with a tow bar, with all wheels on the road, the steering wheel needs to be unlocked so the towed vehicle can follow the tow vehicle. However, when you are towing on a tow dolly, the front wheels are tied down onto the dolly and don’t turn. Therefore, you don’t need to keep the steering unlocked. Since the rear wheels will be on the road and spinning, you need to place the transfer case into neutral and put the transmission into fifth gear.
You also need tow lights and safety chains or cables. Additionally, you should have brakes on the tow dolly that are activated by a conventional and readily available trailer-brake control. — Ken Freund
Trailer Sway Problem
Q: We just bought a Forest River Salem Hemisphere Lite 282RK travel trailer. We pull it with a 2013 GMC Sierra 1500 crew cab with 20-inch tires. I bought five-ply XL tires. We have an Equal-i-zer weight-distributing four-way sway-control hitch, and we drive only 60 mph. The problem is, it still sways — the back of the truck moves back and forth in the wind or if a semi goes by. The dealer put the hitch on. Should I buy a sway-control bar for the truck, or do I need to get a better hitch set?
Tim Almich, Tea, South Dakota
A: The 282RK is 35 feet in total length, has a gross vehicle weight rating (GVWR) of 8,700 pounds and a claimed hitch weight of 700 pounds. These so-called lightweight travel trailers, especially long ones like yours, are more easily moved around because there is a lot of surface area for the wind to blow against and not a lot of weight to keep everything planted. That trailer is also a rear-kitchen model, which may be putting more weight at the rear than other travel trailers, and that can cause unstable handling.
The first thing I suggest you do is weigh the combination on a truck scale and check the axle weights with the truck and trailer fully loaded for a trip with fuel, water and all supplies on board. Make sure the trailer’s weight is properly distributed, loading as many heavy items in the forward storage compartment as possible.
You did not mention if you travel with the water tank full or empty. If the tank is forward of the rear axle, traveling with it full may help stability. If it is behind the axles, you should travel with it empty or with just enough water for flushing the toilet, washing hands, etc., while on the road. Be sure to compare the truck’s rear axle weight to the gross axle weight rating (GAWR) tag, which should be located inside the driver’s doorjamb.
Next, inflate the tires to the manufacturer’s recommended inflation pressure, based on the actual load, by using a load-inflation chart (available on manufacturer’s websites and at tire dealers).
The Equal-i-zer hitch incorporates weight distribution as well as sway control, and it is a proven design that works well when used properly. Verify that the hitch is correctly adjusted, as this sounds as if your spring bars aren’t tight enough, which can lead to unstable handling. — K.F.
Q: We have a 2011 Bighorn 38-foot fifth-wheel. I tow it with a 2003 Dodge Ram 3500 dually. When having to make a panic stop, I do not feel secure in the braking capability it has, and I am considering installing disc brakes. A fellow RVer who had installed disc brakes on his similar fifth-wheel told me he was dissatisfied with the results. He then said he had the disc brakes removed and had the 7,000-pound axle upgraded to an 8,000-pound axle. He said this axle upgrade improved the braking performance. I am undecided on which is the best way to go.
Rickard Standish, Dallas, Oregon
A: It’s possible your friend may have had an improper match between his trailer-brake control and the electric-over-hydraulic disc-brake actuator. Not all brake controls, including some integral ones built into earlier model trucks from the factory, are compatible with all disc-brake units. When they’re set up right, the aftermarket trailer disc brakes are fantastic and slow a trailer down with enthusiasm. Disc brakes are also an improvement over the stock brakes; they tend to get rid of heat and resist fade due to heat buildup on long grades better than drum brakes. — K.F.
Diesel Smell in Cab
Q: I own a 2011 Ram 3500 diesel and have had problems from early on with a strong diesel smell in my cab when stopping at traffic lights after driving 50-plus miles. I have had two dealers check this problem, and neither knows the answer. From looking at the Cummins Forum, I have read about a lot of other people having the same problem. Is there anyone with an answer, or is Chrysler just dodging the problem?
Jerry Dews, Port Neches, Texas
A: We’re not sure if you mean the smell of unburned fuel or the smell of diesel exhaust. When you are having the problem, pull over in a safe spot and quickly walk around the truck, sniffing for the area that the scent is strongest. Pop the hood and look for signs of fuel leakage or the sound of exhaust leaking. The air intake for the cab interior is located at the base of the windshield, so the engine compartment is the likely source of the odor. — K.F.
Q: Had you asked me last fall if I had winterized our 2008 Coachmen correctly, I would have said, “You bet!” This spring when I filled the water system, I found out I did not do so well. There is now a leak in the hot-water tank. Try as I may, I cannot locate a repair manual. Can you help?
Jim Snider, Novi, Michigan
A: If the leak is in the steel-tank part of the water heater, there is probably no realistic way to repair it. A hot-water tank that’s been split or cracked due to the expansion of freezing water would need to be fully removed from the RV, cleaned, welded by a certified welder that can work on low-pressure steel vessels, and reinstalled. The weld would be subject to rusting inside the tank because it wouldn’t be galvanized like the rest of the tank interior, so you’d have rusty water after a short time. In short, if the tank is split and leaking, you’ll need to invest in a new water heater.
If the leak is in the pipes or fittings near the tank, it’s just a matter of following basic plumbing procedures and replacing or repairing the defective parts. — J.J.
The Tech Team
KEN FREUND: Ken is a former ASE Certified Master Technician, service manager and shop owner who has authored numerous books on automotive repair.
JEFF JOHNSTON: Jeff served as technical director of Trailer Life for 20 years and has been an RV enthusiast, mechanic and writer since he could hold a wrench.
RV Clinic from October 2015 Trailer Life