Holding tanks, need help

[twilder]

I have a 1970 25' Trade Wind. I am diving into the underbelly for the first time, this is a recent purcahse and my first RV. I have a leak in the grey water tank that is showing up at the back of the trailer. I am totally confused by this system. The tank appears to be located in the mid section of the trailer. The black water tank at the back. Looking underneath, the tank has an outlet that has a bung in it, with a 3/4" copper pipe coming out of that. Following the pipe to the street side under the hot water heater, there is a tee, with a valvue coming off of the tee. The pipe continues on to the back bumper storage section, where it transitions into a hose fitting. It would appear that this is where to drain it, yet when I put water into the system, it comes out of the dump valve for the black tank ( the side port of the dump valve.) I have no idea what the side valve is for, other than to possibly back flush. I also do not see how to turn off grey water dump. In other words, there is no way to get the drain hose onto the tanks without the grey water coming out all over the place. There is a hand written note that says "drain the grey water first, valve under the hot water heater". But I swear that valve does nothing. Help! Thanks, Tom

[Chuck]

well, I'm not sure I have a clear picture of what you've described, but A/S did not put grey tanks in until 1974. (73 on some models it was an option). My 73 had a tank in the middle of the trailer, but it is for fresh water. are you sure that's not what you're looking at?

the hand written note must mean that your trailer was retrofitted w/ a grey tank....but it is confusing. sounds like they may have set up some way to collect grey water in some external auxiliary tank, but I can't imagine why they would do that

the normal "no grey tank" configuration has a 3/4 inch pipe that enters the 3" dump outlet, below the valve for the black tank. waste water from the sinks and shower just flow right out into the 3" extension pipe, and on to the ground...or down the sewer hose, if it is attached. nobody cared about grey water in 1970. now, they do.

when you say "put water in the system", do you mean "run water in the sink/shower? if thats the case, and it comes out that 3/4 inch pipe and runs onto the ground, it sounds like you don't have a grey tank.

you can get an external tank that has wheels on it that you slide under the trailer to collect the grey water. when it fills, you drag it over to the dump station to empty it. the bigger one's can hook on to your truck and you can tow them over there....slowly!

[twilder]

Thanks Chuck, that helped to unravel the mystery! Yes, I meant by putting water in the system that I ran it through the sinks and shower. It all comes out the side of the dump valve. It looks like somebody added a grey tank to the underbelly. There is a cap that goes onto the dump valve with a hose bib thread on it. Looks like I screw the short section of hose onto that cap, and the grey water travels out of the original dump valve and through the retrofit copper to the new holding tank. I drain that tank with the gate valve that is on the T. Knowing my 70 did not have a grey tank from the factory makes sense of it all now! Thanks!