Well, here's what I've gotten myself into this time.........
From the little bit of research I was able to gather, I went ahead and bought a can of penetrating oil and sprayed down the 20 or so bolts holding the tank pan in place. I read a few stories about rusted bolts that either wouldn't back out, or just snapped altogether. While visually mine didn't look corroded, I figured better safe... than sorry!
There is not a whole lot of room between the ground and the underneath side of an Airstream, however we live in this thing, so raising the chassis up a foot or so would have been ideal, just not in my situation. (and I'm "lucky" enough to be a small dude that can fit in small places & work)
I let the bolts "soak" for a few days, then used some 2X4 pieces to prop the corners of the pan a bit just so it didn't just fall to the ground when I removed the bolts. Luckily enough, all the bolts came loose with no issues. The pan slowly dropped a bit to rest on the lumber supports, and one by one, I worked it to the ground.
**** Be sure that both grey and Black tanks are EMPTY, before you do this ****
From what I've read( and now seen) the tanks themselves are not terribly heavy and the pan itself does most of the support. Once you remove it, basically the vent pipes and the stool flange is all that keeps them from falling to the ground.
There is roughly an inch of cheap styrofoam laid out in pieces on all sides of the pan. These help "support & cushion" the tanks and prevent shifting during travel. I'll likely be replacing the styrofoam with something a bit sturdier. (and cleaner!.... Our tanks have been leaking into the pan.... )
So, I worked the pan out from under the Airstream and promptly into the back of the PowerWagon. It's going to the carwash for a good deep cleaning.
As a precaution, I cut some 2X4's and fashioned up some support across the middle of the tanks. Just to make sure nothing shifts, or drops out of place.
Now that I can see ALL the "workings" of the tank system I can clearly see the issue we're having. But, more importantly I can now determine exactly what parts I'm gonna need.
Here's what I've found....
So, the black tank is on the left and the grey is on the right. I was pleased to see that with the tanks exposed I can also see the tank flush fitting (which stopped working about 6 months ago)
So on closer inspection I can see that likely, the valves themselves are working as they should. The issue I believe is being caused by the (I'm going to call them tank adapters) little plastic black pieces that the valves are attached to. These Adapters are the piece that allows the valves to mount to them, in turn sealing them to the tanks. BOTH of mine are cracked in multiple places. Which I'm sure is allowing liquids from the tanks to weep out of the tanks, into the pan and out of the drain holes.
This would also make sence of the fact that the leak got worse as the tanks filled. ( higher head pressure on the cracked adapters forced more liquid through the fitting)
Here's a few pics of the valves & adapters.....
Bottom of the Grey valve/Adapter.
Bottom of Black valve/adapter
Front view of Black valve/adapter
Look closely at the pics and you can see the broken adapters. The adapters are actually what the valves attach to. The valves attach to the adapters, which in turn attach to the tank.
The breaks are on all sides. What caused them? Hard to say. We have never traveled with anything in the tanks. Never hit any bumps hard enough to bottom out the rear end of the Airstream. (shock) My best guess is age and elements.
Armed with the knowledge I needed I headed off the LazyDays here in Tucson (local Airstream affiliate) for the necessary parts.
Black & Grey valves are the same.. Thetford p/n 08709
I'll have to edit and post later.... They didn't have the "tank adapter" and had to order them from Airstream. I'll get p/n & pics up later.
The tank flush is within reach now that the pan is off. It's located on the street side of the black tank, high up towards the top of the tank, just below the subfloor.
I'm hoping the existing one is "serviceable" as it looks to be made from Brass. This replacement I picked up from Lazy Days looks to have suffered from company cutbacks & executive decision! (plastic junk
One thing I need to figure out is what type of sealant has been used on these connections to the tanks. I can see around the tank flush and also on the adapters that they have used some type of semi-hardening liquid sealant. It looks like when I'm ready to disassemble everything, that this stuff is pliable enough that it will clean up good. Anyone know what it may be? Or, what I should be using during replacement?
More info & pics to follow at some point this week when the rest of my parts arrive.