# Outback Tt Underbelly



## Gr8daggett (Oct 19, 2011)

Hi ... I want to install the Horst Probes in my holding tanks, so ...
I am looking for any tips or tricks to remove the underbelly of my 277RL TT.
From what I hear it is a PITA.


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## CamperAndy (Aug 26, 2004)

What you hear is correct and there is no real tip or trick other then making sure you have a buddy or two that will suffer with you while you take it down and put it back up. Failing that have a couple of jacks and a 2x4 to hold it in place as you attach screws to hold it.


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## thefulminator (Aug 8, 2007)

You can always make an access hatch. See my pics here.

My link


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## KTMRacer (Jun 28, 2010)

thefulminator said:


> You can always make an access hatch. See my pics here.
> 
> My link


that's likely the best choice. I have dropped my underbelly to clean up wiring, add new wiring and insulate the ductwork. However, The underbelly around the waste and grey tanks won't likely drop down unless you do some cutting around the piping anyway. So. When it came time to install the Horst probes, dropping the underbelly worked for the fresh tank, but for the others, I just cut an access flap for the grey tanks and black tank and did the same thing the fulminatr did. At least now if for some reason I need to access the black/grey tank plumbing I can do it without dropping the whole underbelly.

BTW the Horst Miracle probes ARE a very worthwhile addition and well worth the time and effort to install them.


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## Gr8daggett (Oct 19, 2011)

Now this is why this forum is so great !

You all have probably saved me from a lot more gray hairs (only a couple non-gray ones left)and foul language.

Excellent idea with the access flaps. Sounds like I want to avoid a total belly drop if I can.

Have only heard good things about the Horst probes. Horst probe construction makes sense.
Going to place my order and get ready for Spring mods.

Thanks again


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## thefulminator (Aug 8, 2007)

FYI, I used stainless screws and a pressure treated fence board for the frame around the opening. I made the hatch with the "hinge" side towards the front of the trailer. In case I forgot to put the screws back in, air flow will push it closed in place of trying to rip it off. Be careful to make a shallow cut as to not penetrate your holding tanks. I used a retractable utility knife with the blade extension set to match the belly thickness as closely as possible.

I did that mod to install a tank rinser. The year after I installed it, the hose clamp on it snapped while camping. It was easy to slide under the trailer after the water was gone, open the hatch and install a new clamp. If had needed to drop the belly to get in there I wouldn't have been able to do that while camping.


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## Gr8daggett (Oct 19, 2011)

thefulminator said:


> FYI, I used stainless screws and a pressure treated fence board for the frame around the opening. I made the hatch with the "hinge" side towards the front of the trailer. In case I forgot to put the screws back in, air flow will push it closed in place of trying to rip it off. Be careful to make a shallow cut as to not penetrate your holding tanks. I used a retractable utility knife with the blade extension set to match the belly thickness as closely as possible.
> 
> I did that mod to install a tank rinser. The year after I installed it, the hose clamp on it snapped while camping. It was easy to slide under the trailer after the water was gone, open the hatch and install a new clamp. If had needed to drop the belly to get in there I wouldn't have been able to do that while camping.


Say how did you find the right place to make the cut?


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## MJRey (Jan 21, 2005)

If you decide to take the cover off to access the tanks be sure to take note of the screws near the tanks. Some of them are shorter than the rest to keep from going through the tanks. Be careful to note where the shorter ones are when you remove them so that you can reinstall them in the proper place. If you don't it's all too easy to put the wrong one in and put a hole in one of the tanks and that will really be a problem.


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## thefulminator (Aug 8, 2007)

Gr8daggett said:


> FYI, I used stainless screws and a pressure treated fence board for the frame around the opening. I made the hatch with the "hinge" side towards the front of the trailer. In case I forgot to put the screws back in, air flow will push it closed in place of trying to rip it off. Be careful to make a shallow cut as to not penetrate your holding tanks. I used a retractable utility knife with the blade extension set to match the belly thickness as closely as possible.
> 
> I did that mod to install a tank rinser. The year after I installed it, the hose clamp on it snapped while camping. It was easy to slide under the trailer after the water was gone, open the hatch and install a new clamp. If had needed to drop the belly to get in there I wouldn't have been able to do that while camping.


Say how did you find the right place to make the cut?
[/quote]

I took a couple of the screws that hold the underbelly on out and wedged the underbelly away from the frame just enough to be able to shine a light in to see where I was at. I then fished a measuring tape into that opening to see how far from the frame edge I wanted the hatch to be. When I made the first cut, which was perpendicular to the frame on the rear side of where I wanted the hatch, I wedged it open and shined the light it to see where I was. I was able to figure out where I wanted the cuts that were parallel to the frame for the sides of the hatch using that info. If you are in doubt, make the hatch bigger than you need it to be and the area you need to work on should be in it somewhere. Just be sure not to use screws that are longer than the combined thickness of your board plus the underbelly to be sure you don't penetrate the tanks.


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## Leedek (Nov 28, 2010)

Gr8daggett said:


> Now this is why this forum is so great !
> 
> Have only heard good things about the Horst probes. Horst probe construction makes sense.
> Going to place my order and get ready for Spring mods.
> ...


I agree. It looks like a Horst Probe install is coming to town. The video here Horst Probes actually helps me understand what I'm going to find once I get the hatch built. Thanks for the thread here.


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## KTMRacer (Jun 28, 2010)

Leedek said:


> Now this is why this forum is so great !
> 
> Have only heard good things about the Horst probes. Horst probe construction makes sense.
> Going to place my order and get ready for Spring mods.
> ...


I agree. It looks like a Horst Probe install is coming to town. The video here Horst Probes actually helps me understand what I'm going to find once I get the hatch built. Thanks for the thread here.








[/quote]

I've used Horst probes for several years and yes, they do what is claimed and well worth the install. They are not competely foolproof, but very, very close to it. The only thing better is the external capacitive sensors, but they are way more expensive and much harder to install. They are orders of magnitude better than the typical factory probe. Since most/all outbacks have screwed in probes vs. spin welded probes, the install is pretty easy once you get access to the tanks.


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## OutbackOwner (Mar 5, 2009)

I took off my complete underbelly and replaced it with sections 4x8 same material. Used 1" fence boards cut to fit as the joints to screw into. Now if I need to work on something, it's easy to remove one section and a snap to replace.


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