Understanding your RV sanitation systems can prevent some foul problems

Motorhomes are self-contained with a fresh water system as well as holding tanks to handle waste water from the various plumbing fixtures. While dealing with waste water isn’t the most glamorous part of owning a motorhome, it is nonetheless an important part. Unlike a residential plumbing system like in your home, an RV has a number of things that have to be kept in mind and taken care of or else you’ll be in for a few messy and smelly problems. Fortunately, it’s not that bad if you understand how things work and pick up a few tips to help keep them working as it should. Let’s first look at how an RV’s waste water system is constructed.

Your RV Has Two Water Systems – Not One

To begin with, there are really two systems, not just one. The gray water system handles the waste water from the sink drains, shower drain and dishwasher, if equipped. The black water system handles the waste from the toilets. This method provides for two separate holding tanks, one to hold the black water and one to hold the gray. The reasoning behind this began in the early days of RV use. Drainage from sinks and showers contributed more volume than waste water from the toilets and needed to be drained more frequently. In addition, the gray water was relatively clean and could oftentimes be allowed to drain onto the ground, although many locations no longer allow that due to local public health laws. On the other hand, the black water wasn’t very sanitary and needed to be disposed of in a proper dump station or sewer connection. Having the two separate tanks made it possible to have multiple dump cycles rather than dumping all the waste at the same time. Another benefit to the two-tank system is that the gray water tank is relatively clean because it’s mostly soapy water while the human waste and toilet paper found in the black tank can cake up inside the tank walls, causing tank level sensors to foul and give errant readings.

The vast majority of motorhomes have a single sewer connection used to connect the sewer hose to the holding tanks. A pair of dump valves, one for each holding tank, connects via a wye connector to this common outlet. These valves are blade type valves to prevent clogging and can be either manually operated or electrically operated with a remote switch.

Each tank is connected to a vent stack that extends out of the roof to eliminate a vacuum from forming in the tank when draining and expansion as the tank is being used. It also allows for odors to vent from the tank. You may have a pair of vent stacks for the two holding tanks, or they may be tee’d together into one common vent stack. A hood is applied to the vent stack to prevent rainwater or debris from entering the tanks via the vent stack. These hoods can be simple rain caps or venturi style fittings that allow the wind to help ventilate the tanks.

Sensors

Of course, you’d never know when you have to dump your holding tanks without some kind of indicator. Early tank designs used three sensor probes that were inserted into the tank. One was located at the one-third level, another at the two-thirds level and one at the very top of the tank. These sensors were inserted through the sidewall of the tank and would conduct electricity when wet. A wiring harness connected them to a monitor panel inside the coach to display the tank levels. If the tank was full, all four LEDs would illuminate. If the fluid level in the tank reached the two-thirds level, only three LEDs would light up. At one-third, only two would light up and if below one-third, only the bottom “empty” LED would be lit.

This system worked for years but had a few drawbacks. For one, the sensors easily fouled and gave false readings, so it was imperative to keep the tanks as clean as possible. Another concern was their accuracy. If the tank level was just below the two-thirds sensor, it would register one-third full on the display. You might think you have plenty of room left in the tank but all you had to do was add a little bit of water to the tank and it instantly jumped to two-thirds full, so you never really knew exactly how full the tank was.

The next big improvement was the SeeLevel tank measurement system. This system used external sensors that used adhesive to attach to the outside of the tank. These sensors were full length and used radio waves to determine the precise level of the tank’s contents.

In addition, the external mount prevented the sensor from fouling. The only time an errant reading was displayed was if the inside tank wall was seriously caked up and needed a major cleaning. The display panel inside the coach was a digital display that reported in actual percentages, usually with 2-4% accuracy. The displays were available in multiple configurations that could cover the LP tank level if needed as well as switches for water pumps. Multiple displays meant you could have one display inside the coach with a second display in the wet bay. Eventually this sensor technology also found its way into the multiplex wiring systems, such as Firefly’s VegaTouch system, so that it could be displayed on their central touch screen panel.

RV Toilets

While sinks, showers, dishwashers and laundry centers aren’t that much different than what you would find in a sticks and bricks home, the toilets used in an RV are markedly different. A residential toilet has a large water closet that acts as a storage tank for clean flush water. It also has a trap that fills with water to prevent any sewer gas from backing up into the home. When you press the flush lever the tank water runs into the bowel with a vengeance, rinsing the bowl and using gravity to flush the water down into the sewer. The tank then refills with water to be ready for the next flush. An RV needs to conserve water because both the freshwater and holding tanks are limited in size, so a different design is used. In most cases an RV toilet consists of a blade valve that is kept closed except when flushing. These gravity dump toilets are placed directly over the black water holding tank. The blade valve is either operated manually via a foot pedal or electrically via a wall mounted switch. When you activate the flush mechanism, the blade valve opens to allow the waste to fall into the tank below and a measured amount of flush water is expelled to rinses the bowl and provide some water to the holding tank to prevent the waste from drying out.

In some cases, it’s not possible to locate the toilet directly over the black tank. This is especially true when your coach has a 1.5 bath floorplan with one toilet midship and another in the rear bath. In that case, a macerator toilet is used. A macerator toilet uses a motorized grinder to grind the waste up and pump it to the black tank regardless of where the tank is located. Instead of a blade valve, this style does use a small trap filled with water. When you push the flush button, the bowl fills with more water and then the macerator kicks in and pumps the waste through a smaller 1-1/4” line to the black holding tank. Then it adds some more water to the bowl. Macerators are necessary when the black tank isn’t located beneath the toilet. The only real disadvantage to them, other than cost, is that they do use more water when flushing than a direct gravity dump toilet, which can be a concern when boondocking with a limited water supply. However, the extra water used helps to keep the solids in the black tank suspended and will keep the tank walls cleaner.

RV Sewer Hoses and Fittings

You need to have a way to transfer the waste from the tanks to a sewer connection or dump station so that requires a sewer hose. Sewer hoses use a common 3” inside diameter hose with an industry standard bayonet connection. These “slinky” hoses are typically vinyl with a spiral wire reinforcement to prevent the hose from collapsing and come in various grades. The cheapest hoses are very thin and won’t last very long. You will develop pinhole leaks, cracks and tears quickly. Upgrading to a heavier vinyl helps but even with the extra heavy-duty hoses, you’ll still have issues. Many motorhome owners have gone with Camco’s Rhino Flex hoses, which are a step up over traditional vinyl hoses. These hoses can hold their shape more easily and are quite a bit stronger. My personal choice is Valterra’s Viper sewer hose. The Viper hose is unique in that it doesn’t uses any helical wire in the hose. The spiral wire used in typical sewer hoses keeps the hose from collapsing but it also leaves a corrugated interior to the hose, which provides restriction when dumping and lots of crannies for waste sediment to pack up inside the hose. This requires additional water to rinse the hose clean. The Viper hose has no wire and the interior is smooth so it rinses clean. You can also step on it to crush it flat and it will bounce right back, unlike a corrugated wire hose which will remain flat and kinked. It also remains flexible at down to -20 degrees Fahrenheit, so it really blows all of the other hoses away.

Sewer hoses have a male and female bayonet connector so you can connect multiple hoses together if you need additional length. They typically are available in either 10’ or 20’ lengths. I prefer to use 10’ lengths because I can always use two to get to 20’ if I need the extra reach. Plus, I keep a third hose on hand in case I ever have a failure. Various fittings are available to connect to a sewer connection. A campground sewer connection may be as simple as a bare pipe sticking out of the ground or it can be a PVC pipe with either 3” or 4” pipe threads. The most common connector for any RV is a 90-degree elbow with a female bayonet connector to connect to your sewer hose and a long snout to insert into the sewer. Most have a slide-on threaded adaptor that is molded onto the snout. This adaptor has both 3” and 4” male pipe thread so that it can fit either size sewer pipe. If you find you are at a site with a bare unthreaded pipe, you can slide a rubber or silicone donut over the pipe. This will allow you to press the elbow into the unthreaded pipe when necessary. It’s also typically used at a dump station, where the sewer pipe is generally just a hole in the concrete pad. These elbows can also be found in clear plastic so that you can monitor the color of your waste. This is helpful when you are rinsing your black tank and want to know when it is clean. Clear pipes that can be inserted in line with the hose are also available.

Sewer hoses do have limited use because they use gravity to dump. If your motorhome’s sewer connection is fairly low and the campground sewer sticks out of the ground quite a bit, gravity isn’t going to work very well for you on this uphill battle. If it’s not too serious, you can just walk the hose from the coach to the sewer after dumping to drain the fluid resting in the hose manually.

Another option is a macerator. A macerator uses a motor to grind the waste and pump it uphill, similar to a macerator toilet. While a 3” slinky hose has a limited length and cannot go uphill, a macerator uses 1-1/4” or 1-1/2” hose that can pump uphill up to 9’ vertically and 100’ horizontally. Some of these models, such as the SaniCon Turbo, are installed permanently in the RV and feature a 3” bypass port for a slinky. Other models are portable and will connect to the coach’s bayonet fitting on the dump valve wye. They are a bit slower to dump that a 3” slinky but offer the ability to overcome gravity when dumping your tanks.

Operation and Cleaning

Your gray water tank isn’t very fussy. As long as you scrape the heavy stuff off your dishes before washing them and keep from pouring oils and fats down the drain, your gray tank will remain pretty clean. The soapy shower water and dishwater help keep the inside of the gray water tank clean so that your sensors won’t give you any trouble. But your black water tank is a bit pickier, so you’ll need to pay attention to it to prevent any issues from appearing. The biggest problem with black tanks is that the waste can dry and cake up on the inside of the tank walls. This leads to unreliable sensor readings. The most important thing is to keep the waste fluid and don’t let it dry out. Saving water can be a disadvantage in that respect.

It’s possible to use a gravity dump toilet with very little water usage. When the toilet’s blade valve opens, the solid waste and toilet paper can just fall through the gate and lay in a lump beneath if the tank is low on water. With continued use, this “pyramid of death” builds and you’ll need a construction crew to break it up. Avoid this by using plenty of water when you flush the toilet. When you dump the black tank, be sure to add plenty of water to the tank so that you aren’t starting out with a dry tank. This water will help to keep future waste additions soluble. Some users like to keep their gray tank dump valve open, but this can lead to a tank with dry sediment caked in it over time. It also allows for certain insects to leave the sewer and enter the coach – you may wind up sharing a shower with them.

Many black tanks will have a flush mechanism installed. This is basically a spray head that sprays water around inside the tank. In some cases, this sprayer can rinse down any accumulated waste that is caked on the tank walls. In other cases, it’s limited to merely pushing any loose sediment on the floor of the tank to the dump valve. Frequent use of the sprayer whenever dumping the black tank is recommended. If you wait too long, the waste will cake up on the walls and be much harder to remove. If you find that this is the case, it’s best to mix up a solution of Pine Sol and fill the tank to about ¾ full, then drive to your next destination. The sloshing action while driving will help rinse the tank walls and put everything into suspension. Then dump immediately after arriving at your destination and finish off with the tank flushing attachment.

Never leave the black tank dump valve open when camping or you’ll experience severe caking and bad sensor readings. Always keep the valve closed unless dumping. It’s a best practice to always dump your gray tank after the black tank. The onrushing flow of soapy gray tank water will help flush any black tank residue from your sewer hose.

If you dump the black tank too often, you’ll never get the water level high enough to prevent waste from caking on the upper portion of the tank walls. Be sure to get the fluid level up high enough before dumping. Ideally, you can do this after a day’s drive to derive the benefit of the sloshing that has taken place. Also be sure to only put human waste and approved toilet paper into the black tank. Never put facial tissue or feminine products down the toilet. You don’t have to buy expensive “official” RV toilet paper from an RV dealer or camping supply store. You just need to use a septic safe paper that will dissolve and break up in water.

You can test your choice of paper by doing the Mason jar test. Place a wad of toilet paper into a Mason jar and fill it about ¾ full of water. Screw on the lid and shake it for about 15 seconds. The wad of paper should now be dissolved into a bunch of fluff suspended in the water. If it is – you pass the test and it’s RV safe. If it’s still a wad of paper and hasn’t broken down – don’t use it in the RV because it will plug up the system.

Chemicals and UViaLite

This brings us to chemicals. A common misconception is that you need to add RV-specific chemicals to treat your waste tank. This is not quite true. Both human waste and toilet paper will dissolve in plain water. You don’t need tank treatment chemicals to do that. If you neglect your black tank, you may need some heavy-duty tank chemicals or Pine Sol to clean it but under normal use, you won’t. One thing chemicals do is deal with odors – although that’s not all it’s cracked up to be either.

Some chemicals are nothing more than perfume. They don’t remove the odors, but they mask it by adding a more favorable scent to the tank. Other chemicals include enzymes that do react with the odors, but enzymes are organic organisms that take 5-7 days to become active. Most RV owners don’t wait that long to dump their tank, so they are basically flushing away good money every time they dump.

A great system that I am familiar with is the UViaLite system. I first noticed this system when reviewing an American Coach for a magazine article I wrote for another publication. I also noticed this system on a Thor diesel coach on another article and have since learned that other manufacturers are looking at implementing this system.

UViaLite uses proven technology that uses an ultraviolet light set to a specific frequency of 185 nanometers to react with oxygen (O₂) to create ozone (O₃). This unit picks up fresh air from beneath the coach and passes it through the UV module and into the top of the tank via a 1-1/4” PVC pipe. There are no moving parts because the system uses the chimney effect of natural airflow rising through the tank’s vent stack. 6 to 20 PPM of ozone are created in the unit and the thermal updraft of the vent stack draws the ozone into the holding tank at less than 1 CFM. Once powered up, the unit can remain on and only draws 0.8 amps of 12 VDC power, which is around 10 watts. The unit can remain on until the user stores the RV at the end of the travel season.

Ozone is a powerful oxidizer that will kill bacteria and chemically destroy viruses in seconds. The ozone generated by the eco-friendly UViaLite attacks the molecular bonds of viruses, bacteria & mold, breaking them up into harmless water vapor and carbon dioxide (CO₂). UViaLite removes the stinky smell caused by hydrogen disulfide in the tank by converting it to freshwater vapor and sulfur that falls out of the air and into the tank.

Eliminating odors rather than masking them with a perfumed scent will make a big difference whenever someone flushes the toilet, especially when the bathroom exhaust fan is on. Because it also kills any pathogens, it will prevent viruses shed from a sick person from wafting up out of the tank and possibly infecting other people in and around the coach. UViaLite does not affect anything in the liquid portion of the tank so it won’t affect any chemicals you may have in there. It only affects the air above the liquid, which is where the odor is anyway.

Keep in mind these few tips and you’ll qualify as an RV sanitation expert in no time!

Mark Quasius is the founder of RVtechMag.com, the past Midwest editor of RV Magazine, writes for numerous RV-related publications and a regular Contributor to FMCA’s Family RVing Magazine. Mark and his wife Leann travel in their 2016 Entegra Cornerstone.

Towing without a supplemental braking system is dangerous RV driving

A motorhome is an excellent choice for traveling. Everything is self-contained and you have the comfort and security of sleeping in your own bed and cooking your own food. The only caveat is that they are large, so using it as a daily driver to go shopping or sightseeing in a national park just doesn’t work out very well. Fortunately, motorhomes are equipped with trailer hitches, making it easy enough to tow a smaller vehicle for your touring while the motorhome is parked at your campsite. Towed vehicles can include a vehicle placed on or in a trailer or loaded onto a tow dolly, but the most common method is to use a tow bar to flat tow your vehicle – commonly referred to as towing four-down.

There are a number of vehicles capable of being towed four-down but there are exceptions, so you’ll need to check with your manufacturer to see if your choice is flat towable. If it is, the next step is to verify that your coach is capable of towing your vehicle of choice. Larger Class A coaches have ample capacity, and some can tow as much as 20,000 lbs. but some smaller Class C motorhomes may only have a 3,500 lb. towing capacity, which will limit you from towing any vehicle that exceeds that weight rating.

In addition to the rating stamped on the trailer hitch, you’ll also need to look at the Gross Vehicle Weight Rating (GVWR) and the Gross Combined Weight Rating (GCWR) of your motorhome. The GVWR shows you the maximum amount of weight that the motorhome can safely weigh. The GCWR indicates the maximum safe weight of both the coach and any trailer or towed vehicle and will always be higher than the GVWR. For example: if you have your coach loaded to the maximum GVWR (let’s just assume 32,000 lbs. as an example) and your GCWR is rated at 36,000 lbs. it leaves you with 4,000 lbs. as the maximum safe weight of the towed vehicle or trailer. Your trailer hitch may be rated at 10,000 lbs. but you must limit the towed weight to the lesser value of the hitch rating or GCWR. If you do not load your coach to the maximum GVWR, then the difference between the GCWR and your actual coach’s weight when fully loaded will increase and you may be able to tow a bit more than the 4,000 lbs. in the above example.

The GCWR also assumes that you have brakes on whatever is being towed. If you have an enclosed or flatbed trailer it will most likely have brakes on those axles that are designed to work in conjunction with a brake controller in the tow vehicle. As long as you have installed a trailer brake controller in your motorhome, you’ll be fine. But when you flat tow another vehicle – it’s a different story. A car, Jeep or truck has its own braking system that is controlled by the driver when driving that vehicle. When you hook up to a motorhome to flat tow the braking system on the motorhome and the braking system on the towed vehicle are two separate entities. They do not work together, so you have no towed vehicle brakes when towing.

Fortunately, there are a number of third party supplemental braking systems on the market that will allow you to safely tow your vehicle and be compliant with the GCWR requirements.

Questions sometimes arise as to the legality of towing without a supplemental braking system, which varies according to state or province. I’ve also heard a few arguments from RV owners about not spending the money on a supplemental braking system because “you can hardly feel the towed vehicle behind the coach”. While the towed vehicle is a small percentage of the total weight, especially on a large tag axle diesel pusher, tests have proven that there still will be a difference in stopping distance during a panic stop. A study taken by Roadmaster and published on their website showed a 34’ class A motorhome took 132 feet to come to a complete stop from 50 miles per hour. When a medium size car was connected to the motorhome the stopping distance increased to 209’. When a supplemental braking system was added to the towed vehicle this distance decreased to 137’. Those extra 72’ can make the difference between safely stopping in time or being involved in an accident should an emergency stop be required.

Another reason for a supplemental braking system is to protect yourself and others during a breakaway situation. Some systems include this and some offer it as an optional accessory, but in either case this is something that every supplemental braking system should have. A breakaway system consists of a switch that is mounted on the towed vehicle and is connected to the coach via a small steel cable. Should the towbar fail or for any reason the towed vehicle becomes disconnected from the coach while driving, the cable will activate the breakaway switch and the supplemental braking system will apply the towed vehicle’s brakes to safely bring the vehicle to a stop and prevent a runaway that could possibly impact another vehicle.

I recall one incident I experienced where a supplemental braking system with breakaway device saved me from some major damage. I had recently rebuilt my towbar and decided to replace my locking towbar and hitch pin set while I was at it. Shortly after we left for a long trip and not more than an hour down the road, I heard and felt a large jerk on the back of the coach. I looked in my rearview camera and saw that our Jeep was following us about 10’ back from the coach. I knew that something had failed in the towbar, so I pulled over to the side of the road and got out to investigate. I saw that the main 5/8” hitch pin that holds the towbar into the coach’s hitch receiver had failed, allowing the tow bar to pull out of the hitch and drag along on the ground. The safety cables held and kept the Jeep behind me and the breakaway cable applied my M&G supplemental braking system on the Jeep, keeping it at a distance from our coach. Had I not had a breakaway system, our Jeep would undoubtedly have plowed into the back of our coach once I attempted to slow down, damaging both the front of the Jeep and the rear of the coach. Our safety cables were stretched beyond being useable but I had kept the old set of locking hitch pins and a spare set of safety cables along, so I replaced them, reconnected the towbar and happily went on our way with no damage to either vehicle.

Types of Supplemental RV Braking Systems

Supplemental braking systems are available in several different versions. Some systems are portable and can be taken out of the vehicle when not needed while other systems are permanently installed into the vehicle. In either case, these systems will provide supplemental braking ability to the towed vehicle. Both methods have pros and cons so let’s look at the differences and see which method works best for you.

Portable systems are placed upon the floor of the driver’s footwell. They operate by actuating an arm that clamps onto the brake pedal. These units use 12-volt battery power to actuate the arm that connects to the brake pedal and use decelerometers to detect when the vehicle is decelerating. The main module is a box that contains the mechanism and sensors and rests on the floor, but generally must be placed against the driver’s seat so that the box stays in place when the brake pedal arm extends so that the box doesn’t move instead. Some of these systems may have additional brackets to help keep it from sliding while others simply rely on the seat cushion to prevent it from moving rearward when the brakes are applied. If you want a portable, you’ll have to consider how soft your seat cushion is and whether that will affect your choice of portable braking system. Popular systems are available from a number of manufacturers, such as Blue Ox’s Patriot 3 system, Brake Buddy’s Classic 3 and Select 3 systems, Roadmaster’s Even Brake system and Rvibrake’s Rvibrake 3.

Another caveat to a portable system is that they still do require some installation, so you can’t just drop it into any vehicle and expect it to work. You will need to mount a breakaway switch to the front of your vehicle and run its wires back to the footwell where they will plug into the brake controller. You’ll also need to provide a 12-volt power receptacle to plug the unit into. Many cars will have a 12-volt receptacle that is connected to the ignition key switch. That won’t work because the receptacle will not have any power when you are towing. You may have to install a constant-hot receptacle someplace in your dash area.

While these installation tasks are minor compared to a system that is permanently installed, you still have to deal with setup every time. This begins by placing the unit on the floor and connecting the clamp on the arm to the brake pedal. Then plug in the breakaway wires and power cord and position the unit so that it can’t move backward when the brakes are applied. You may also have a calibration routine to go through, depending on the manufacturer of your braking system. Once you are done towing you will have to disconnect the wires, remove the clamp from the brake pedal and find someplace to store the system.

The last consideration is that these systems use sensors to sense when the vehicle is decelerating because there is no communication between the towed vehicle and the coach. If you are using the coach’s Jake brake to slow down when descending a downgrade, the supplemental system will unnecessarily apply the brakes on the towed vehicle because it assumes you are braking. This can result in excessive wear and heat buildup when traveling in the mountains.

A system that is permanently installed takes a bit more labor to install but, once installed, it’s pretty much a hands-off forget-about-it system. The simplest is NSA’s ReadyBrake, which is permanently attached to the towbar. This is basically a surge brake system that senses the forward pressure of the towed vehicle under braking. As the module moves, it pulls on a steel cable that runs through the towed vehicle’s engine compartment to the area around the brake pedal. This cable attaches to the brake pedal and applies pressure to the pedal in response to the pressure applied to the towbar mounted actuator.

A number of popular systems are available for gasoline powered motorhomes. These use an actuator that attaches to the towed vehicle’s brake pedal, generally via a cable. The cable is behind the brake pedal so it doesn’t get in the way when driving the vehicle. Most use a decelerometer sensor to sense the rate of deceleration but are also connected to the motorhome’s brake light switch so that the brakes will only apply when the driver steps on the brake pedal in the motorhome, preventing any brakes from dragging when descending steep grades. Common systems include Brake Buddy’s Stealth system which is a dual-mode system that can also use the cockpit-controlled module to actuate trailer brakes as well as towed vehicle brakes.

Other systems are Roadmaster’s InvisiBrake and Demco’s Stay-In-Play Duo. These systems can be used on diesel powered coaches as well, but they lack the true proportional braking available from a system that is designed for a coach with air brakes.

With a diesel-powered coach that has air brakes, you have lots of choices. If you recently upgraded from a gasoline-powered motorhome to a diesel pusher, you can continue to use your existing towed vehicle’s braking system. Or, you can upgrade to a pneumatic system that utilizes the air pressure from your coach’s air brake system to apply the brakes on the towed vehicle. The biggest benefit is that you can now get true proportional braking because the brakes on the towed vehicle will apply in the same amount and at the same time as the brakes on the motorhome. The harder you step on the coach’s brake pedal, they harder your towed vehicle’s brakes will apply. You can now coast and descend grades without any worry about prematurely applying or dragging the towed vehicle’s brakes.

These systems involve the installation of a module under the hood that generally actuates a cable that pulls on the back side of the brake pedal arm. This module connects to 12-volt battery power to operate the breakaway valve and in some cases will operate a vacuum pump to provide a source of vacuum to the brake booster behind the master cylinder so that the power brakes are in operation. A pair of wires runs to the front of the vehicle and connect to the breakaway switch while a small air hose also runs to that area to serve as a connection to the coach’s air brake system. In addition to the usual trailer light umbilical, a steel cable for the breakaway switch and an air hose are also used to connect to the rear of the coach.

Some diesel pushers come from the factory prepped for supplemental braking systems and have a quick disconnect coupler at the rear of the coach. If not, you can get a DOT approved kit to allow your diesel chassis to do that. You can’t simply tee into a brake line some place or you may risk a loss of brake pressure on the coach should the air hose to the towed vehicle fail. These systems will add a small air tank and the necessary valves to isolate the towed vehicle’s supplemental braking system from the coach’s brake system to prevent any failure from affecting the braking of the coach. The most popular pneumatic true proportional systems are the M&G Tow Brake and Demco’s Air Force One.

Note that either of these systems can be used on a gasoline-powered coach but it requires the purchase of an installation kit which includes a 12-volt air compressor that converts hydraulic brake pressure to pneumatic so that you can deliver true proportional air to the towed vehicle. These optional kits are a bit pricey but do give you true proportional braking and your towed vehicle will be ready for a diesel pusher if you decide to upgrade later on.

Selecting the correct system will depend on your needs. If you tow multiple vehicles and don’t mind living with the lack of true proportional braking and storage issues, then a portable system might be your best choice. If you want an “install once and forget about it” system, a permanently installed system should be your choice. If you are reasonably talented, you might make this a DIY installation but if not, you’ll want to have it done correctly by a certified chassis tech, such as those at National Indoor RV Centers. Electrically operated systems can be used on both gasoline- or diesel-powered coaches while pneumatic systems that tap into your coach’s air brake system can give you true proportional braking that will match the application of your coach brakes and prevent any false readings that can occur from inertia sensors used on many electrically operated systems.

Regardless of which system you prefer, it’s important to have a good supplemental braking system with a breakaway switch to be safe when towing. Towing without one is dangerous and is tantamount to driving without insurance and throwing out all your fire extinguishers. It’s just not an area to ignore.

Mark Quasius is the founder of RVtechMag.com, the past Midwest editor of RV Magazine, writes for numerous RV-related publications and a regular Contributor to FMCA’s Family RVing Magazine. Mark and his wife Leann travel in their 2016 Entegra Cornerstone.