Question about black tank connection

Hopefully there is never a next time. But if there ever is, there is a simple way to prevent drips while working. Gravity is your friend.

Find a way to park the trailer so the valve is on the downhill side of the tank. For a north or south valve just use the jacks to tilt the trailer. For east west pull the tires up onto some lumber or up on a curb.

After it drains all night reverse the tilt and go to work drip free.

BugsRLB wrote:
Sorry I was a little late with the ratchet strap idea! We tried everything as you probably did. Pry bars, wood wedges, brute force, swearing etc. Manufacturers should allow a little play in the pipe. Cause sooner or later, it's gonna need replacing.

Better late than never, as they say. Although I may still have such a strap from the days I used to tie down my motorcycle on the back of my Class C I don't have any with me at this time. I might have gone out to buy one as a last resort upon your suggestion.

Don't get me started on what RV manufacturers should do, LOL.

Sorry I was a little late with the ratchet strap idea! We tried everything as you probably did. Pry bars, wood wedges, brute force, swearing etc. Manufacturers should allow a little play in the pipe. Cause sooner or later, it's gonna need replacing.

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!

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!

https://rvtipoftheday.com/general-tips/barker-auto-drain-waste-dump-valve/

opnspaces wrote:
I use plumbers silicon lube to hold the seals in place for assembly. If you are worried about the grease trapping particles think about gravity and just don't grease the bottom 1/3rd of the seal. But seriously the grease is not going to hurt anything. And the grease will allow you to slide the valve into the joint without dislodging the O-rings.

As said leave the white section alone unless you want to create a leak. Just scrape the bolt heads clean. And no you do not have to reapply the goop that you scrape off.

Thanks again.

While I would expect more debris to flow by the bottom of the black valve I expect the whole valve is exposed to it. The valve becomes completely submerged as the tank fills, does it not, and water and debris in the tank is agitated with every flush and while driving.

I'm not sure how much difference a little plumber's grease would make in the long run in terms of either collecting debris or lubing the seals but if I can get the valve and seals into place without it I will. If I need to I may try some plumbers grease or a little crazy glue on the valve side of the seals so that pieces of the seals won't get permanently stuck to the pipes.

Tangentially, have you ever tried that trick of drilling a hole in the valve body for squirting in some lube using the straw on a spray can of silicone lube when seals get sticky? I've seen a few videos of this on YouTube. I am tempted to slice a valve in half to see what it looks like inside in order to see/learn more.

I use plumbers silicon lube to hold the seals in place for assembly. If you are worried about the grease trapping particles think about gravity and just don't grease the bottom 1/3rd of the seal. But seriously the grease is not going to hurt anything. And the grease will allow you to slide the valve into the joint without dislodging the O-rings.

As said leave the white section alone unless you want to create a leak. Just scrape the bolt heads clean. And no you do not have to reapply the goop that you scrape off.

Not real sure I would use the superglue. To seal, O-rings need to stay flexible.
For years, on many applications I have used grease to hold O-rings in place for assembly. This place I would use Vaseline or some such.

CA Traveler wrote:
X2 above. Be careful with the installation that the 2 O rings remain in place.

Thanks.

I have seen suggestions online to use various kinds of lube to help hold the seals in place on the valve while installing it but I don't think that's right. Conflicting info suggests anything like that can capture debris in the valve. Plus, we know that certain chemicals can damage the rubber seals. Also, the instructions on the Valterra valve packaging don't suggest any such thing. They do say to place the seals on the pipes before inserting the valve. If I find I have to keep them on the valve while putting it in place I may use a few tiny drops of cyanoacrylate (super glue).

I did the job on a different RV years ago and it was a nightmare because it was nearly impossible to spread the pipes to remove / install the valves.

Home Skillet wrote:
DO NOT mess with the white section.
Just unbolt the the valve and slide the new one in.
You will have to scrape away the white sealant on the bolt heads.

10.4. Thanks.