Question about black tank connection

BugsRLB wrote:
First and foremost DRAIN and FLUSH the black tank very well prior to disassembly!

As said, remove the 4 nuts and bolts from all four corners. Separate the black pipe on the right away from the from the blade valve. Insert new blade valve and bolt back up. I had to put a ratchet strap to my axle and "gently" move the black pipe back enough to get the new blade in with messing up the O-rings.

My cable was sticking as well and the blade was leaking. For the cost of a manual valve and cable and an electric valve, I chose the electric. Push button, valve opens. Push button, valve closes. Perfect!

Thanks again.

The job is done.

First I drained and flushed the tank with the built in San-T-Flush sprayer system. Then I refilled the tank and included 1 gallon of bleach which makes a disinfecting solution for 48 gallons and let it sit for an hour or so. Then I drained and flushed two more times and left the valve open overnight to allow for anything that would trickle out to do so.

Despite the fact a couple of the bolt heads on the old valve were covered with a hard cement that had dripped onto them at the RV factory during assembly making it impossible to get a wrench on them I was able to get the bolts out of the old valve easily enough by removing the nuts and tapping lightly on the bolts to drive them out.

The old valve came out without too much fuss but a trickle of water began to flow. I used an old dish pan to catch it. I also slowly pressed up on the bowed-out belly of the tank a few times which was below the drain level and this caused a gallon or two more water to come out. After that it didn’t drip any more.

It was a nightmare getting the new valve and seals into place. I wound up wedging a piece of 1 x 2 wood between the flanges and sprayed some WD-40 Specialist Silicone Lube (safe for plastics and rubber) on the outer surfaces of the seals and portion of valve casing that needed to squeeze between the flanges and was able to wiggle the new valve and seals into position.

I put about 10 gallons of water into the tank and let it sit for an hour or so to leak test the new valve. Then I added more water and waited awhile. Finally I brought the tank up to about 50 gallons and waited overnight. I used a garden hose water meter to measure how much I added to the tank. No leaks.

My old valve, BTW, failed prematurely because ABS cement dripped into the blade track during assembly at the RV factory and was also protruding past the end of the pipe at the flange which deformed one of the seals. Sloppy workmanship.

BTW, your ratchet strap idea is pure genius!

Thanks to everyone for your help!