RV Doctor Column RV Doctor #284 Dear Gary, I recently purchased a 1997 Coachmen travel trailer. By the time I got it home, I was sure it had no brakes. Now I want to test them while parked before tearing into them. Please give me some tips. Gene Starns, (Salem, OR) Good idea Gene. First thing; position the trailer on a flat section of roadway or driveway and leave it connected to the tow vehicle. Set the emergency brake on the tow vehicle. Raise one side of the trailer so that both tires on that side are off the ground. Place two safety jack stands under the frame on that side. Now, by hand, spin each tire on that side and activate the controller from inside the tow vehicle. Each tire should immediately come to a stop. Spin each tire again and this time depress the brake pedal in the tow vehicle. Again, they should immediately stop. Try a third spin test and this time pull the pin on the break-away switch located on or near the "A" frame of the trailer. When they lock, you should not be able to manually spin either tire. Be sure to reset the pin fully into the switch so as not to drain the battery. By the way, it is recommended that one side of an axle and the opposite side of the other axle be inspected at least once a year. Now is just as good a time as any for this inspection. Look closely at the electrical connections of each magnet behind the backing plates. Are they secure; clean, dry and tight? Look for abnormal wear patterns on the brake shoes and an uneven pattern of wear on the brake magnets themselves. Also, the drum, armature and all mechanical components should be checked. Replace like components on each end of the same axle regardless of the condition of the opposite side. For instance, if the left side magnet of the forward axle is in need of replacement, replace both magnets on that axle even if the right side looks okay. Keep like parts the same age on the same axle. Check the outer bearing during disassembly for the brake inspection and repack if necessary. Check the shoes and around the backing plate for evidence of a seal that might need replacing. Consult the axle manufacturer's recommendation for mileage intervals for packing and replacing the bearings and races and repack if necessary. After reassembly of the brakes and while the trailer is still on jack stands, spin each tire once again and activate the trailer brakes one last time to be sure. If the brakes need adjusting, fully tighten the shoes to center them inside the drum; so tight that you cannot spin the tire by hand. Then back off the adjustment so that the tire will spin about one revolution by hand and you can still feel a slight drag as the tire goes around. Finally, take the rig for a road test keeping in mind it still might be necessary to adjust and fine tune the brake controller. Dear RV Doctor, I am in need of relocating my sewer holding tank. Are there any basic guidelines for length of pipe to tank and angle from toilet to holding tank? My holding tank used to be located directly under toilet until I upgraded my receiver hitch and went to a Class III. Now there is no room for the tank. Gene Barrows, (Savage, MN) Gene, in order to maintain code compliance, the 3-inch drain pipe from the floor flange into the top of the holding tank can be angled at not more than 45 degrees. Do not use any 90-degree elbows; horizontal runs are not allowed since the drain flush is propelled by simple gravity and there is not near enough water pressure or volume from the toilet to keep a horizontal drain unobstructed. You didn't state what brand or model RV you have, but for this to work there must be enough vertical clearance between the bottom of the floor and the top of the tank for two, 45 degree, 3-inch ABS fittings, plus a connector pipe between them. Also, do not forget to keep the continuous vent pipe from the top of the tank up through the roof. It must maintain a minimum size of 1-1/4" diameter. On the outlet side of the tank, the termination valve, (dump valve), must be located within the first 36" from the outlet. New holes can be cut into the top of the tank once the location is marked and rubber grommet-type fittings used to connect the drain and vent. If the original toilet inlet and vent connection are not utilized, the holes can be patched by welding a piece of polyethylene plastic over them. Of course, if they are threaded fittings, simply install the appropriate pipe plugs. This is not a typical modification and I would wonder why the holding tank had to be relocated in the first place. Adding a receiver hitch, even a Class III, does not usually necessitate relocating the holding tank. Are you sure you have the correct hitch installed? Dear Gary, is it necessary to put a board under both wheels when leveling a fifth wheel trailer or is it adequate to just raise one wheel. Bernie Waltzer, (Riverside, CA) Bernie, on many RVs, damage to the sidewalls of RV tires is a common result of using improper blocking techniques during the leveling process. Always use a support board wide enough and long enough to fully support the entire footprint of each tire that needs to be raised. In a pinch, your suggestion probably wouldn't hurt for a quick over-nighter, but try to avoid this habit when possible. Raising only the one axle will eventually cause undue and uneven stress on the springs, shackles and mounts. It's much better to take the time to support both tires equally on that side. Dear RV Doc, what is the best thing for motorhome batteries during the winter? I have a new motorhome and this will be its first winter. Should I leave the batteries in and keep the coach plugged in or should I take them out and store them for the winter? How about the engine battery? Some people take them out, some people leave them in. Which is best? If I take them out should they be charged once in a while? Gil Rousseau, (Ludlow, MA) Gil, it is always recommended to completely remove all the batteries during a harsh winter. Fully charge them before storing them in a clean, dry location in a warmer shed or garage. Avoiding freezing temperatures will eliminate the fear of the water freezing in the electrolyte since a fully charged battery has less water and more sulfuric acid content than a discharged battery. There is probably no need to apply a charge during the actual storage period, but fully charge them just prior to re-installing them in the spring. It is only advisable to leave the RV plugged in during the storage period if the coach is equipped with one of the newer, computer-controlled battery chargers. Otherwise, there is a great risk of overcharging the batteries.
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