Let's talk air bags...

[Ford_6L_E350]

Originally Posted by Pschitt

Jage, why did you install two gauges? One for each side? Do you plan to have different pressure for right and left airbag?

Two gauges is common. One gauge can be used , but you need independent switches to select the side you want to check.

The two airbags need to be separated, not on the same air line. If they were connected, it would cause the van to lean more in a corner as air moved from the outside air bag to the inside air bag.

Mike

[BrianW]

Has anyone here used a dual-needle gauge, like this one from Viair? http://www.summitracing.com/parts/var-90083/overview/

I'm wondering how they work. I can't seem to find a picture of the back connections anywhere. Do they have two inputs for two different airlines? Or do you need an activator box or something?

I was thinking about trying to fit a single gauge in something like a trailer plug mounting box and attaching it to the side of my hitch, and mounting the inflation valves under the bumper just above it.

I haven't eyeballed a plug mounting box in person to see if it's big enough for a gauge, but it looks like it might be: http://www.etrailer.com/Accessories-and ... 18156.html

[carringb]

I have the AirLift two-needle gauge. Works great. Really demonstrates weight transfer in the twisties, since the needles will move opposite from each other. There are two inlet ports on the back, and it's a standard 2-1/8" gauge which fits in my pillar pod along with my other gauges.

[Ford_6L_E350]

Originally Posted by BrianW

I was thinking about trying to fit a single gauge in something like a trailer plug mounting box and attaching it to the side of my hitch, and mounting the inflation valves under the bumper just above it.

If you have your license plate mounted in the bumper, the plate mounting screw holes can be used for the two air line fittings (Schrader valves). Did that on my P/U camper and it worked great.

Mike

[jage]

I wanted a dual needle, but the place with them in stock would have added an hour to my drive- plus just one dual needle gauge was double what I paid for both gauges, extra tube and connections.

The nice thing about the mechanical system is there is zero power connections. Each gauge just has an inlet, which is why I needed a T for the valve. Some of the kits have dual needle gauges and they have a port for each needle, plus some are lighted.

[4MacFam]

Quadvan installed my air bag system and I asked them to do separate lines to each side. They installed a dual gauge that was lighted but didn't hook up the light because it's kind of bright and on the dash it would be annoying. The picture online doesn't show both needles, mine has a black one and a red one. They also installed two separate "sliding switches" (not sure what you call them) for each side next to the gauge to fill and drain the bags. Works great.

Nice job on your project. I like to see other guys that save "junk" (as my wife calls it) because you never know when you might need/use it.

[jage]

Originally Posted by 4MacFam

I like to see other guys that save "junk" (as my wife calls it) because you never know when you might need/use it.

Got to be careful though, it can get overwhelming. My rule of thumb is I have to have a specific project in mind or I cannot collect/save it. Plastic and plates are notable exceptions as they are always useful. But if I can't say "I'm going to do X with this" it goes- for example I have an old electric chainsaw that I'd like to try making a bike engine out of. I still have more projects than time however!

As far as the airbags, the gauges indicated a leak in the passenger side and it turned out to be a threaded fitting. I was surprised, because they were benchmade there is no excuse for loose. Regardless it saved me triple checking everything with soap- because I'd still be paranoid I had a leak.

This thread has been super helpful and all the advice and parallel adoption has been invaluable!

[Chance]

Originally Posted by Lizard1

.......

Discuss.

In my opinion it’s important to remember that airbags can indeed level an overloaded vehicle, but they don’t actually change axle loads appreciably. The vehicle can “look” as if loaded normally after being leveled but it will remain (over)loaded the same for the most part.

By comparison, weight distribution hitches as recommended by others above will not only shift some of the trailer tongue weight to the trailer axles (thereby reducing tongue weight on van) but will also transfer some of the remaining trailer tongue load from van’s rear axle to front axle. With extended body Ford vans that have a long rear overhang this is particularly beneficial when towing a heavy trailer; otherwise tongue weight will unload front wheels excessively.

As others have experienced and reported above, adding airbags to a vehicle with leaf springs doesn’t necessarily improve ride because it makes suspension stiffer. Many normally think of airbags as softening the ride, but two springs in parallel will normally be stiffer than either alone. And since ride is usually harshest when vans are empty because leaf springs are already too stiff for lower load, adding air bags can be moving in the wrong direction as far as a smooth ride goes.

A pure air-bag suspension system would be a great way to go in my opinion because suspension stiffness can be increased or lowered nearly-proportional to load. If someone made an excellent aftermarket kit that wasn’t too expensive I’d consider upgrading my E-350 to rear air suspension similar to that used on new Ram pickups or the upcoming 2014 Mercedes Sprinter. I've looked but have never seen one I feel is worth installing. If someone knows of one or has used one maybe they'll post it here.

[jage]

Some results in my towing thread:
viewtopic.php?f=6&t=11114&p=102472#p102472

They were definitely well worth it for this trip.

[carringb]

Originally Posted by Chance

In my opinion it’s important to remember that airbags can indeed level an overloaded vehicle, but they don’t actually change axle loads appreciably. The vehicle can “look” as if loaded normally after being leveled but it will remain (over)loaded the same for the most part.

I don't dissagree with that. But keep in mind the vans look like are dragging a$$ without being overloaded. Nothing wrong with that, other than headlight aim. And hitch clearance. But mostly it just doesn't look right.

And yes, they do improve the ride on the vans when they are loaded. At least with the stock springs. Keeping weight off the lower over-loads makes a big difference because that lower spring has double the spring rate of the rest of the leaf-pack.