Accessing the undercarraige (?)

[Airobert]

Recently bought a '74 Overlander. So far all of my questions have been answered here doing searches! This is an amazing resource. The issue I'm working on now I had trouble searching for because I'm not even sure what you call what I'm looking for...

I have gray water leak just forward of the bumper, right around where there are tubes coming out (look like overflow vents?) on the bottom rear corner of the unit (its a rear bath model). The leak is quite old, because there is a lot of rusted and rotted away metal there.

First of all, what do you call the protective layer that covers the entire underside? I'll call it the "underbody" for now. And then more specifically, it looks to me that I'm going to have to cut away sections of the underbody to find the cause of the leak -- the leak seems to only be coming after water runs (thus part of the gray water system) and is not leaking above the floor level, so it seems like attacking it from underneath is the way to go.

So, I'm wondering what the standard cautions are for removing pieces of the underbody, and then, assuming I find the problem and fix it (might be other questions when I get in there), how I go about patching a new piece over the repair?

Thanks in advance for sharing your wisdom and experience with another new owner!

P.S. I have no cell reception or internet service at the new place, so I might only check back ever other day or so when I get into town, so, sorry in advance if I'm slow on responding.

[Flynavy]

The covering you are referring to is called the belly pan. You remove it by drilling out the rivets which hold it in place. If it is in decent shape you can save it and reattach when you are done.

I had a leak in the same area on my 74 TWind. I started by cribbing the coach up 6" to give myself room to work.

When you get the pan off you will find soaked insulation along with who knows what else, but you will be able to track down the leak. Mine turned out to be the shower drain.

Get someone familure with jacking and cribing if you have no experiance with this yourself. You will want the coach rock solid as you will be working under it for a while.

[Schu]

On a 1974 there will be styra-foam insulation under the tanks. Both black and gray tanks are in the same location-forward of the bumper. The underbelly should come down to expose the tanks. You will want to be careful if you do any drilling in that location and make sure tanks are drained first. Also do not be surprise to find the tank support steel or cross members to rusted and or missing.

[overlander63]

And to add to Schu's post, if everything is still intact, there are nuts and bolts holding the brackets that hold the holding tanks. If you're lucky, you can remove those fasteners, and the rear of the tanks will drop down a bit for inspection and possible repair.

[Aage]

It may look something like this drawing. My rear bath '74 31' Sovereign is exactly this layout.

[Airobert]

Thanks so much for the info! I'll be working on this over the course of the next few days. Not sure how I'll be "cribbing" it up, but I'll look into that too.

[Flynavy]

To get the coach up in the air, first make sure you are on a level spot so it doesn't want to roll. Level it up with the a-frame jack.

Jack up one side( making sure the jack is in the right place) until you can slip a 2x6 or wider under the tires. Let the jack back down, then do the same on the other side. Lower the a-frame jack to bring the coach back into level. Keep repeating until you get it up enough to work under it. Try to keep it as level as you can. Once you get it up high enough, it's a good idea to block the tires so it can't roll. I put mine up 6" and I had plenty of room to work, even for an old fart.

[Airobert]

Thanks again for the wonderful advice. In the big picture I have so many projects to deal with, this one ended out moving down the list a place or two. I did test the exit valve from the gray water holding tank, and it only leaks when that is *open*, implying that the leak is south (or downstream) of the tank, which is probably a good thing.

New inverter... leak under the sink... broken door latch... installing a functional lock... and then the gray water leak. I can hold the water in the tank, and then empty it with a tray to catch the water under the leak for now. I have to resort to a lot of temporary fixes like that for the short term.

An example is my door handle mechanism -- the inside handle stopped working. After taking it apart - to make a long story short - I drilled a 1/4" hole through the door and back plate, so to get out of my trailer I use a wooden dowel (from the inside) to physically push the outside handle open. It's not elegant, but it at least I can get out.

It's all an adventure!

[pgr32e]

If it only leaks when your dumping the tank, it could be as simple as the seal that joins the outlet pipe to the valve. Mine was really old large O ring. If you want, I think the seals are still available and the pipe assy. just slides rearward after disconnecting the outlet fitting from the bumper. Better than taking out the tanks. I didn't think much about the whole O ring idea so I replaced the whole assy. with new pipe and clamped it in place with regular clamped adapters. Good luck.......Phil.