A little background to this story.…..In the summer of 2021 our original black tank had a major failure- sadly solely by human error. We had inadvertently threw “on” the tank warmer fuse during our MORryde install. The PO had not installed a heat override- so if you install tank warmers please also install that auto sensor override. The tank was empty and ended up frying itself and tearing substantial cracks in several areas of the bottom. Hard lesson learned. We thought we had solved the problem when we found a highly rated RV repair shop about an hour from us who specialized in plastic welding, repairing all sorts of “plastic issues” with RVs. He looked at the tank and felt sure he could repair it. We had been told by many that it was near impossible to find tank replacements, some had tried their own repairs to no avail and we even contemplated going with a composting toilet instead (in the end…nope not for us!) So…. 3-weeks and $600+ later, the multi-layer repair looked and worked awesomely. We were all set!! Needless to say removing a black tank and replacing a black tank is not for the fainthearted. We are eternally grateful we have a nice concrete floored garage to work in and higher ground clearance thanks to our MORryde Independent Suspension system install. We did successful camping trips in August and September- all systems were GO! The black tank was working just fine! For more about our original project click here.

FAST FORWARD TO JULY 2022

At the very last official stop on our 5-week RV trip through 7 states in June/July of 2022 we were at our last campground, Campfire Lodgings outside of Ashville, NC and atop a huge mountain! Lo and behold, we saw a slow leak coming out onto the beautiful concrete slab RV pad. We had a 3 day stay here so we quickly hooked up our sewer hose and kept the bayonet valve open (we normally never do this!) so that any liquids would go out to the sewer rather than drip. That did a pretty good job but we also used the campground bathrooms during the day and as much as possible (we were in bear country so I was not going to go out to walk to the bath house for my nature call at 2 AM!). We allowed the tank to dry out and the leaking stopped. TIP: In a pinch we turned off the water feed to our toilet and lined our toilet with boondocking camp toilet liner bags and improvised for the 2 day drive home when needed. These are easy enough to dispose of at rest area dumpsters.

The good, the bad…and the downright ugly!

Once back to our home RV storage barn garage we took to task removing the old (repaired) tank. These tanks come out a lot easier than they go in. We have found the toughest part is getting the discharge piping lined up and the bayonet valves in place. Those valves are actually the toughest to do- you need five pairs of hands and only have room for 1 pair in that outside compartment.

Steps to remove your black tank:

In our 1987, 32S we have a mid-bath. This means that our black tank is also under the area where our REAR Stabilizers are. These must be removed first.

PREP: Before beginning this project, if your tank has been used somewhat recently and may not be completely dried out we recommend using a Camco toilet and tank washing wand (we actually do this routinely at least 2-3 times per year when RVing part time. We will do it more frequently once we go full time). by hooking up a garden hose (not your fresh water hose) and using this pressure washing system through your toilet by holding the foot pedal down. They also make some that have a sink attachment end on a short hose. Extend the wand end down right into the tank and rotate it around all sides of the tank as much as possible. Hook up your sewer hose to drain out tank. We did this multiple times ensuring we had removed as much as we could.

• Remove the belly pans underneath your black tank area. *TIP: be sure to label each of them on the underside first so you can easily see how they go back in. Sometimes you feel like you are working with a jigsaw puzzle.
• Remove any insulation (ours has sheets of foam insulation bats all over the length of the trailer put in by a PO.)
• Disconnect sewerage discharge pipe at the black tank opening. Keep rest of discharge piping from the elbow and as it goes through to the bayonet valve in the wet bay area.
• Disconnect the vent stack connection (our 32S it is in the corner of the cabinet near the furnace)
• Disconnect toilet and remove bolts and flange (should screw off with some force used)
• once all pipes have been disconnected….
• Unbolt the steel “L” channel that runs along the rear side of the black tank and holds it snugly to the front brace.
• Remove tank slowly maneuvering it out of its location pulling down.

SOURCE FOR NEW BLACK TANKS: We were very fortunate that we were given a great tip from Chuck Cayo (recognized as a national guru on all things Avion. His family started the Avion Corp back in the day). Chuck suggested we call Pelland Enterprises. Their website is quite extensive and we were able to find the perfect replacement for our needs. The new tank is slightly smaller (shorter in length) than our original so holds perhaps a couple gallons less but the other dimensions were perfect including the location of the main discharge hole and width and height that would fit into our original location. If you have a 32S feel free to contact us for our exact model we ordered. Different trailer models and lengths will have different size needs.

https://www.pellandent.com/RV-Holding-Tanks

Here is a diagram we made to show Pelland Enterprises exactly where we needed them to spin weld in (best way to do) the opening for our vent stack and for our toilet opening. They will do this step but be sure your measurements are clear and exact because all tanks are not returnable! We uploaded tons of photos and these drawings to them via email. Also note, it takes approximately a minimum of 6-8 weeks for delivery.

Once we received our new black tank, it was time for installation. Basically we reinstalled going in the reverse of our above steps.  Thankfully we were able to do the pipe hook ups relatively easy this time.  Once the pipes were reinstalled, we tested the tank and the connections by filling the tank with water thru the toilet pipe opening in the bathroom floor.  Kevin opened the bayonet valve to discharge the black tank and we watched for any signs of leaks.  All went super well.  Ditto for the grey tank with similar testing to ensure no leaks in the reconnected pipes and the bayonet valves.

At the instruction from Chuck Cayo we went ahead and once again installed a marine plywood board (coated several times with a marine epoxy resin “West System*” on all sides and edges) and positioned it in place covering the entire tank bottom, and extending about a 1 inch on the rear edge.  This board we strapped in with metal L brackets held in place to the frame pieces with self riveting screws. We have the some of these products we used listed on our Amazon Favorites list on our Resources & Links page on our website.  TIP:  Per Mr. Cayo and our own experience, it is VERY IMPORTANT to put a large board under all of your tanks to support them.  Only metal strapping is not enough-even if you never travel with stuff in your tanks.

Once the pipes were all reinstalled we purchased 2″ R-10 Styrofoam insulation boards (pink) at Home Depot and cut them precisely to fit around the tank and rest of underbelly area.  See photos below.

BUTTONING UP THE BELLY PAN:  Once all of the layers of insulation were put in place, Kevin re-screwed in (stainless self taping screws and in some places, rivets) the belly pan sections.  We have actually created a drawing showing how ours goes together including which panel goes under a neighboring one when installing.  The copper gas line was installed back in place outside the belly pan area with some rubber lined clamps screwed into the aluminum pan sheets.  Reminder, the gas line, by law must always be on the outside!

WET BAY FINISHING UP TIPS: Then we applied a spray in sealant foam (pest retardant type) around the openings where the grey and discharge black tank pipes come through the wet bay wall aluminum.  This helps to keep rodents from accessing into the belly pan area. TIP: Be sure NOT to get this anywhere near the bayonet valve areas themselves.  Also, while in this area, Kevin applied lubricant to the steal rods in the bayonet valves themselves.  The best lubricant to use here is dry silicone spray and prime the rod pushing the handle in and out several times.

TOILET REINSTALL:  once all the underbelly work was done we reinstalled the toilet.  This was also a great time to do a deep clean of the toilet’s main discharge shoot from the bottom up to the under side of the ball valve (the thing that opens and shuts during flushing).  Not a fun job but good to do when the toilet is uninstalled and then applying dry silicone gel around the toilet ball valve and replace all gaskets and seals. We also took many photos of the manufacturers labels and ordered back up parts while they are still available and we will have them on the road should a failure of some part happen. All were found on Amazon. Our toilet is Thetford Aqua Magic Plus II, porcelain bowl. The “plastic skirt” that wraps around the base is not shown in this photo

WHILE WE WERE AT IT WE ADDED A NEW FEATURE!: Since the toilet was off we also took advantage and ordered the spray hose with handle accessory and installed that before reinstalling the toilet itself. TIP– on our previous post and videos about our replumbing with PE piping we showed how we installed a shut off valve on the toilet water intake hose just to the left of the toilet base. This made removal of the toilet or any work needing to be done to it far easier than having to turn off all your water in the rig.

We hope this article may help you with some tips, or if you ever need to replace YOUR black tank. We sincerely hope that day will never come though!

If you found this article helpful please drop us a comment!

Be well and safe journeys! Kevin & Luise