Newbie black tank valve access question

[chrishunnicutt]

2nd shakedown trip in our 2013 3750FL was a great trip. No issues to speak of until at the dumping station. Hooked up my rinse down hose and started the rinse down before pulling the drain. Added enough water to get the tank to read at 3/4 full and add volume for flushing. I have a close off valve at my bayonet fitting and that was open. I pulled the black tank release and it started to empty. I let it run until it started to run clear then I shut the black tank valve to allow it to fill up again. After a few minutes I pulled the black tank release again and allowed it to run clear. I didn't have anyone waiting so I decided to run the cycle one more time. I ran it a third time and noticed some tension in the release valve tension. It opened and cleared. I turned off the rinse down and emptied my gray tanks. When I went to go close the black tank valve it wouldn't budge. It actually has a little play in like the far end has come loose. My concern is that even though I have a safety valve at the bayonet I have no way to close off the black tank.
How do I get to the far end of the pull rod? I can hear it moving when I try to pull it out or push it in. Whats the best way to lower the belly cover? I have an extended bumper to hitch warranty but I'm hoping its a quick fix I can do myself without having to carry it in to the closest Camping World. Any help or input is greatly appreciated.

[bncinwv]

On our 3750, the nut on the back side of the valve rod came loose. I made a small square cut beneath it in the underbelly material to place the nut back on. Repaired the cut with black Gorilla tape that was still holding when we traded the unit for our current one.
Bingo

[chrishunnicutt]

I will check that, thanks! I did loosen the screws that hold that section of belly wrap in place to see if I could see under the lining but there was another layer of what looked a silver insulation blanket. I can hear and feel what sounds and feels like the far end of the rod or cable hitting the wrap. I think its pulled out of or separated from the valve but cant see it to confirm. I don't want to cut the lining if I don't have too but have been told if I take it in to be serviced that's what they'll do as it's all one piece of the coreplast.

[Carl n Susan]

On your Montana the black tank and the shower tank are both in the dropped frame section. Both valves are at the back of the tanks near the end of the dropped frame. Access to the valves is actually easy without cutting the Coroplast.

Remove the 6-8 self tapping screws which hold the Coroplast to the frame. You may have to loosen a bracket holding the propane pipe but that is a snap too. Roll the Coroplast forward to expose the valves.

I suspect you have a pinched seal in the valve. Had the cable come loose, you would be able to pull it out a loooonnnggg way without much resistance. And it would go back in a similar manner.

Here is a posting from earlier this year which does a good job of explaining how to change out a valve.

http://www.montanaowners.com/forums/showthread.php?t=66825

[chrishunnicutt]

Thank you! I actually read the thread you referenced while I was researching the issue.
When I go underneath all of my visible propane pipes are forward of the axles. Which end of the drop framed section do I start to remove the screws to roll the Coreplast back? I removed several where thank valve handles are thinking I would be able to see the valve but no luck and no way to roll it up as the grain of the Coreplast runs from side to side. The tire carrier in the rear will prevent it from rolling back very far on that end. Is there a diagram of the layout anywhere?


This is the reason why I joined and enjoy this forum! Thanks again for the advice.

[Carl n Susan]

The dropped frame portion starts at the front of the RV and ends in front of the wheels. The 3" sewer line exits the dropped frame at the rear of it. This is where you start removing the screws. There should be three or four of them running perpendicular to the length of the trailer including the plumbers tape near the sewer pipe. Then start removing the screws along the frame, starting at the rear, until you can see the valves. It sounds confusing but it really isn't.

I assume the 3750FL has a similar tank layout to my 3700RL. I would be very surprised to learn they are different.

I can get a picture later today if that would help.

[chrishunnicutt]

That would be awesome and thanks for the explanation. I started taking the screws out yesterday to the rear of the 3 inch drain as its very close to the access hatch for the valve handles. The belly material is all one piece with no seams so I was hoping to be able to reach it from the side. I don't see any screws running perpendicular to the sides and my drain exits the belly material behind my rear axle and almost directly behind the rear tire. All the screws I saw where either in the outer frame or where pipe/line hangers had been screwed to the frame. I assume there is cable connecting to the valve somewhere on the drain above where it exits and close to the tank. (thinking they wouldn't run more drain than necessary) On mine the 3inch drain actually exits the pan behind the axles so all of that is up in the frame behind the rear tire. I don't know how long that cable is but I can hear and feel it touching against the belly liner about 3-4 feet in from the handle. Again my assumption there is a radius of cable needed to make the turn to get to the valve. Any pictures or diagrams you can provide would be great!

[chrishunnicutt]

As soon as I can figure out how to post a picture in here I will and show the layout.

[Carl n Susan]

Apparently there are differences in the routing of the 3" sewer line between out rigs. But I am willing to bet the tank locations are similar. Find the spot where the 3" sewer line exits the dropped frame. The Coroplast forward of that point is what has to come loose. You will only need about a foot or two detached from the frame in order to access the valves.

The valve cables are anchored to the wall with the pull handle and the valve. The rest of that 6' long cable is loose in the belly pan area.

This picture shows my 3" line exiting the dropped frame and then making a turn to the street side. Remove the self tapping screws along the back edge of the dropped frame.


This picture shows the screws down the left side of the dropped frame. I removed the ones from the back edge to the cross brace about 2' forward. Do the same thing on the right side.


Now you should be able to see into the valve area. You should also be able to roll the loosened Coroplast towards the front of the RV to facilitate valve access.

If this doesn't do it for you I am going to have to go to my dealer and look at the plumbing on a 3750FL.

[chrishunnicutt]

Mine comes out vertically right behind the rear tire on the driver side. :-) I see now what you were referring too about the perpendicular screws from your picture. Unfortunately mine isn't plumbed like that. I believe my black tank and rear gray tank are just slightly over the rear axle and back while the front galley tank is just over the front axle forward based on where their plumbing comes through the liner. Based on what you've described and what I've read elsewhere here my valve should be close to where the 3 inch line exits the liner. I'm going to take the screws back out on the side again tomorrow and see if I can get to it if I can get the silver insulation blanket down as well.

[Carl n Susan]

I stopped by my Montana dealer today and checked out a 3750. OMG the plumbing is totally different from what I had seen before. Now I understand the confusion between us.

I see the coroplast runs a long distance before and after the the tank and the sewer drain line come down through it. I think your best access will be by cutting a flap in the coroplast (and the silver insulation material) rather than trying to get it out of the way. Gorilla Tape is the favorite way to close up the flap when you are done. My 2005 had Gorilla Tape closing flaps I had cut for tank and sub-frame access for 7 years and were still intact when I sold the RV.