Need info on installing a dump valve

A dump valve will not raise the dumped axle.
The tires will still be on the ground.
Dumping the air on the rear axle will reduce the scrub pressure and make the trailer steer/pivot on the front axle.
Not something to do fully loaded as you will overload the front axle.
Less scrub less tire wear and a better turning radius (watch the tail swing though).

 

Flyer: you are going to have to do some extra plumbing

1. Plug one rear feed (at the front)
2. Tie the two rears together
3. Install dump valve in the rear feed line

 

That won't work. You have to keep each side separate or it will turn you over in a curve.

 

Perfect! Simple isn't it?

WHAT WHAT WHAT? Oh snap January Fool's Day joke!

 

I suppose that might be possible on paper but, only with really large hoses and no anti-roll bars on the suspension.

I am not a guru but, I have never seen a large hose system that did not have anti-roll bars.
Actually the only large hose systems I have seen are on the back of a tractor and they use short bags and have anti-roll bars.

The HCV does not keep the sides separate all 4 are tied together, so what keeps it from rolling over then?

 

That looks good.
My only concern would be that the HCV (it appears) is not on the axle being pressurized and could lead to some funky behavior, especially when on uneven ground.

Keep in mind that the DOT bumper may drag on steep inclines (driveways) with the rear axle dumped.

 

The valve has a line for each side. They are isolated inside the valve.