Rear compartment leak

[TheBluebird]

Hello, I have a leak in my rear compartment with the water swelling the fiberboard on the interior wall of the compartment on the entry door side. I replaced the compartment door seal but that didn't seem to fix it. Could I have an interior leak? I looked at the diagrams and can't tell if there are water lines near there (from the bathroom sink, I suppose). Does anyone have any suggestions how I might access this area or test whether it is rain or plumbing. I am now fulltiming it in this, thanks.

[Blue~Go]

Yes, there are both water supply and drain lines in or near that compartment. Supply to bathroom sink, supply to toilet, supply to outdoor shower in some cases (think yours is on the side though). The waste drains for the kitchen sink, toilet, shower, and bathroom sink are also in that area. If you remove the driver's side compartment wall (may need to remove back wall too) then you can see all of this plumbing -- and also see how you can increase storage in that compartment

A couple of thoughts:

1) It doesn't take much water to damage the MDF "walls." Like, teaspoons. They are little sponges.

2) Water can easily run "downhill" from the entry point to where you find the damage. In other words, where you see a problem may not be super close to where the water is getting in (or it might be). Depending on how you are parked or slanted, "downhill" can mean different things. I find I'm rarely parked perfectly flat (even on a flat surface as my Chinook is "perky" in the stern). The entire floor of the Chinook is flat except for a very few places (water heater "tub," cab floor, entry steps, generator box). Other than that it's pretty much flat, so water is free to roll around.

3) You could put some food grade coloring in the water system to see if it's a plumbing leak. Could be, but I think leaks around outside openings are more likely. OTOH, have you noticed any leaks when it's NOT raining (or hasn't rained recently)? Do the "leak" events have anything in common (like it happens when you run water, it happens when you flush the toilet, it happens when it rains, when you are parked a certain way, etc.

4) Typical places are penetrations in the shell. The one-piece shell means there are no seams between panels, but of course windows/hatches/lights still mean holes. Any Chinook is old enough that things may need to be re-bedded (meaning, remove the thing, clean up the old bedding, re-bed under the flange, re-install the thing).

Some possibilities:

1) Rear hatch door seals (COMMON), or rear hatch frame surround.
2) Running lights
3) Door frame
4) Door lockset
5) Refrigerator lower vent (COMMON culprit).
6) Base of waste tank vent on roof
6) Any of the mounts for things on the roof (railing, vents, ladder, etc.).

Etc.

[dougm]

Pay attention to your water pump. If the system is water tight with no leaks the pump should only turn on when you actually open a faucet or flush the toilet ect.... if you hear the pump turn on for no apparent reason randomly threwout the day its a good indicator that the system has a leak someplace. On my concourse the bathroom sink had a PEX fitting that had aged enough it was leaking water causing the water pump to turn on randomly to build up the pressure again that was being lost from the slow leak. I exhausted my search and finally yanked out the interior of the trunk area and sure enough there was water dripping. When i finally found it and started unscrewing it from the bathroom sink faucet the fitting literally fell apart in my hand. With that said i decided every fitting in the rig was most likely the same age as the one that failed so i replaced all of the PEX lines as well as every PEX fitting on it just for peace of mind. Mind you i did not opt to use sharkbite fittings, i purchased the clamp crimper tool, tubing cutter, clamps, and all of the clamp style PEX fittings at Lowes. I just do not trust those sharkbite fittings. Its just to much work to go about it the lazy cheap way imo.

[chin_k]

Is this the compartment behind the spare tire below the outdoor shower? I have similar problem there, and it is due to the bathroom faucet not tighten onto the fiberglass sink, so whenever people used it to wash their hands, the small amount of water pooled near the cold/hot water handle will leak down below. This is the first issue I fixed when I got my rig. I removed the faucet and reinstall it with chalk so that the water will not leak below into the compartment. You can test this by purposely pour water around the bathroom faucet and see if you can see the water drips down below.

As for the MDF, it is *not* a sponge. It is more like baby diaper that will sponge up the water *and* swell up 20 times of volume. For sponge, you can squeeze the water out, and when it dries up, it will return back to original. Not with diaper/MDF... well, I never try to recycle baby diaper, so maybe diaper is just like sponge...

[Blue~Go]

As for the MDF, it is *not* a sponge. It is more like baby diaper that will sponge up the water *and* swell up 20 times of volume. For sponge, you can squeeze the water out, and when it dries up, it will return back to original.

Too funny! As I typed the word "sponge," I thought "but wait, a sponge is supposed to get wet and doesn't get ruined by water..."

[kdarling]

When I took off my running lights to scrape away all the years of accumulated caulking, I was amazed at the size of the light holes underneath. So yeah, check those.

In my case, though, a rear leak turned out to be a single long top ladder screw. The leak then ran along the underside of the roof to the door, hiding its origin.

Kev

[eporter123]

Check the rear brake lights. They are held in with 4 screws (which are probably loose) so pull them out and take a look inside. One of mine was leaking, so I added butyl tape all around the opening. The other side was also really loose, so I tightened up those screws. That seemed to fix both leaks.

I have another healthy drip back there that seems to be coming from the bathroom toilet tank vent hole. It's too cold right now to chip away the goopy sealant on top, so I patched w/ some butyl tape on top.

[Blue~Go]

Check the rear brake lights. They are held in with 4 screws (which are probably loose) so pull them out and take a look inside. One of mine was leaking...

I think Blue Bird's year of Chinook has the later Ford Explorer (Expedition?) taillights. They don't screw in but are a press fit. They can be identified by the three-part "Michelin Man" bulgy look vs. my era (probably same as yours) which are the stock Ford van taillights of the time. Smooth faces, black rubber trim around the edges, and screws.

[sdblacksheep1]

Discovered that the carpet in the rear compartment was soaked, as was the particle board used to build the storage box. Turns out the J PVC fitting from the bathroom sink was cracked, and it appeared a previous owner tried to patch it. Didn't hold. Why even try that for a $6 part. Had to rip out the carpet, part of the sub-floor, and the waterlogged box. On the bright side, might as well add in a storage compartment accessible from the inside, as there is some useful wasted available space back there.

[chin_k]

For most case, PVC is not worthwhile to patch/replace, unless someone just can't figure out where to buy the part, or how to install it. Too bad that you have to deal with someone else bad decision.