'79 Safari H2O tank drain help

[apltrez]

I am working on a , new to me, 79 Safari 23. After 2 Argosies and a couple of Casitas, I think I know what I am seeing but need some more experienced eyes on it. On the underside of the tank, inboard, between the axles, is where a drain valve should be. I jacked the trailer up and set it as high as I dared on Jack stands to inspect the underside of the tank cover and some time in the past an inspection/repair port with a cover plate has been done...quite helpful. The pictures that I will try to attach will show what I found which appears to be the threaded port for a drain valve at the low, outboard, side edge..maybe 3/4 " and a larger port... maybe 2 in. in the bottom with a threaded plug that seems to be leaking

The PO said that he had only over used the pump to drain the tank and he was the second owner and had bought the trailer, worked on it a bit and never used it before selling. According to him this is the way it was when he got it. It is a NM trailer and I am in NM.

Freezing isn't a big deal but still I am a bit concerned. Has anyone seen a set up like this where the tank is drained through the system, by the pump?

My plan would be to take out the larger plug, clean everything up and install a new plug/bushing with a radiator pidcock in it and leave the side valve off...hence pumping the tank out than open the pidcock for any residual and the balance will likely dry out in a week or so in this climate.

Help & Thanks

Greg

[dbj216]

Hi from frozen Minnesota. I often drain my fresh water tank with the pump. I have that "winterizing port" on the inlet side of the pump where I can draw in RV antifreeze to the pump and suck down a gallon or so to fill the fresh water system with RV antifreeze and thus protect it from -3 below zero like this morning. When I open the port, I "assume" the little bit of water in the inlet tube from the fresh water tank to the pump drains back in to the tank.

I am not concerned about an inch of water in the bottom of my fresh water tank freezing up over the winter. So I don't open the cheap plastic drain valve that is stuck anyway.

Your photo shows an old plastic tank with "spin welded" fittings, a very common practice with molded tanks. That plug in the 2" port may be good and stuck. The spin welds won't take a lot of torque. So if you can break it free without much force, go ahead and plumb in a petcock drain. If not, then leave it. It is not worth cracking your tank to install a drain valve that you really don't need.

By the way, there is no charge for my advice!

David

[apltrez]

Thanks David

Also thanks for the torque advice. I had thought if it didn't come easily I would drill it, at the center and progressively larger until I can break the old fitting out repace it and then plumb to the street side wall of the tank cover and then use this flange, from EBAY, with a pidcock and some clear tubing.?????

RV FRESH WATER DRAIN VALVE FLANGE 3/8" or 1/2" WON'T FAIL EVER AGAIN, WHITE!!!

Total: $23.45
Seller: brucejonh (3299) Item Id: 171070722860

[dbj216]

That looks like a reliable petcock valve. We use them at work all the time. The outfit I work for makes fuel tanks as well as other products. It will likely have a right hand thread on it, so it opens by turning counter clockwise, backwards from what a guy might think.

Good idea to drill out the plug in the spin weld. Even a hole saw might work to weaken the plug until it collapses. You have to preserve the threads in the spin weld fitting, so take your time with it.

The ad is sure right. Those cheap plastic RV valves just don't last very long. Mine was stuck shut. I just use the pump to run the tank low. Good enough for me.

David