Patch, Repair, Or Replace?
Dear RV Doctor:
We own a 1999 National RV Tropi-Cal motorhome. The gray water tank leaks when it reaches about two-thirds full. The tank was installed on the chassis over the gas tank. The floor and bathtub were then installed over the water tank. Because of this installation, there is no way to get to the gray water tank to repair it. We dry camp a lot, and this leak has become a real problem. Do you have any ideas about how to fix it? Is there something we can put into the tank that would seal it from the inside, or a way to get to it that we haven’t considered?
Gary Shuchat, F173605, Cape Canaveral, Florida
It’s quite unfortunate that National RV is no longer in business and that they installed the holding tank buried like that. In any case, you’ll have to find some way to expose the location of the breach.
Typically, nothing connects to the sides of the holding tank with the exception of the monitor probes and possibly a hose fitting used to flush out the tank. All waste plumbing and vent stacks must enter/connect to the top of the tank. The good news is that all holding tanks are constructed of polyethylene or ABS, both of which are a type of thermoplastic. That means it can be heated and cooled numerous times without changing the molecular structure, so plastic welding is the preferred repair method. Even though epoxy-type repair kits are offered in the aftermarket, they are best described as a temporary patch only. The only surefire way to repair a plastic holding tank is by plastic welding.
Unfortunately, I do not know of any product you can pour down the drain and have it seal the leak. (You were thinking something such as Bardahl’s Radiator Stop Leak, right?)
According to your description of how it was installed, I’m guessing that the tank was mounted in a stressed situation and a crack developed somewhere on one of its sides. As the tank filled, the extra weight added more strain and the crack got bigger.
One important code requirement is that all holding tanks must be removable. That said, it may be necessary to half disassemble the motorhome in order to remove it, but it has to come out of there somehow! The best scenario is that you can locate the crack or hole with the tank installed by removing minimal components.
Plastic welding requires special equipment, and not all RV repair facilities are so equipped. You’ll have to locate a shop with a plastic welding machine. Welding with hot air or nitrogen is the only cure that would warrant a guarantee. A simple patch using a kit may work temporarily, but it likely will leak again at some point.
With all that said, you have to decide whether to patch the tank temporarily, fix it permanently, or replace it altogether. Only you can decide. Start by trying to locate the leak visually. The degree of difficulty to do that may determine your ultimate decision.
Relocating A Vacuum Cleaner
Dear RV Doctor:
I have a 2007 Monaco Type A motorhome. The central vacuum canister is located in the curbside storage compartment and takes up space, sticks out, and blocks the movement of stored items. I would like to know whether there are restrictions related to moving the vacuum to the driver’s-side water compartment (behind the water management panel) where there is enough access room to change the bag and filter. Just a small amount of tubing and some wire would be needed to accomplish this. In the compartment where the water heater and furnace are located, there is also plenty of free space. What are the rules for drilling small mounting holes in the compartment walls that appear to be white PVC? I would greatly appreciate your input.
Ivan Montague, Brandon, Mississippi
It is indeed possible (and logical) to relocate the existing vacuum system to a more suitable spot in the motorhome. Sometimes, I think, design engineers view a floor plan without deeper thought concerning practical usability from a motorhome owner’s standpoint. With storage space at a premium on most coaches, it makes sense to consolidate equipment if possible.
From a tubing standpoint, as long as a bunch of elbows aren’t required to facilitate the move, you should be fine. If you must turn corners to make the connections, try to use longer, sweeping elbows instead of quick-turn elbows. Also, when extending the conductors for any 120-volt-AC circuit, be sure all connections are created in a dedicated junction box equipped with a blank cover plate. Use the proper size wire nuts and apply black electrician’s tape to secure the wire nuts to the conductors. If your vacuum motor happens to operate on 12-volt-DC power, there is no requirement to encase the connections inside a box, but it is preferred since they must be kept clean, dry, and tight. You certainly wouldn’t want to accidentally disengage any of the wires.
As far as drilling and mounting anything to thin plastic or metal, the preferred method is to use bolts, nuts, and lock washers. If you cannot gain access to both sides of the PVC wall you mentioned, a device called a nutsert — a threaded insert — can be installed into the plastic panel to receive the mounting machine screws or bolts. You can watch a video that shows the operation of a nutsert at http://goo.gl/GMnN8. You may have to click on one of the nutserts in the list to see the animation.
Be aware of how thin the PVC partition may be. If it’s too thin, it might not support the weight of the vacuum even if it is bolted through. Also, be aware of what is behind that panel before you drill holes into it!
Replacing Roof Vent Lids
Dear RV Doctor:
We recently were caught in a hailstorm that damaged the three roof vents on our 2001 motorhome. I have looked through the literature and searched online, but I cannot come up with the manufacturer of the vents so I can replace the covers. I really don’t want to replace all of the vents. The one in the bathroom has a fan, but the rest are nonmotorized. I hope you can help.
Ray Wayne, Neoga, Illinois
You did not mention what brand motorhome you have, but a call to the manufacturer should be your first course of action, if possible.
A few different suppliers sell14-inch roof vents for the RV market. Aside from proprietary vents, you’ll also see brands such as Ventline, Jensen, and Elixir, which manufactured both powered and nonpowered roof vents. Most have an “old style” and a “new style” to consider, but I’m certain yours can be found in the aftermarket. You just have to identify the type you have on your motorhome. Then you’ll have to choose between transparencies. Replacements are available in plain white, smoke, amber, and even aluminum.
Look closely at what remains of your vents. There should be identifying marks somewhere on the lid denoting the manufacturer. It also may be labeled somewhere on the ceiling assembly inside. All offer replaceable lids, so I understand your reluctance to replace three entire assemblies. Just a little more sleuthing is all it should take. Perhaps a local dealer can help identify the brand and type on your motorhome.
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