Older Air Suspension ?s

[eric1514]

So I have this new to me 2006 Isata 250 and I can't find out any information about the air suspension that was factory installed on it. For instance, what is this?



I know that's an air line quick connect, but why is it there when I have these



in front of each rear wheel opening?

I don't see an onboard compressor or air pressure guages anywhere.

I guess my questions are, what is the point of this system and how do I operate it?

TIA,
Eric

[bclemens]

1. are you sure that rear port is not an LP quick connect?

2. If you go to the Dynamax website and click on brochures. https://dynamaxcorp.com/brochures at the bottom of that page is a drop down for "archived brochures" there is a brochure in there for a 2006 E-series. Also there is a supplemental owners manual that might have some specific info.

[eric1514]

1) I'm not entirely sure about the LP thing but it seems to be fed by a 1/4 inch black plastic hose. Unfortunately, or fortunately depending on how you look at it, that plastic line disappears into a mass of foam insulation.

2) Thanks for the link. I'll take a look right now!

[eric1514]

Well, that was a bust. I downloaded a copy of the Supplemental Owners Manual because there's some other go info in there but it only mentions the air suspension in passing when referring to the HWH levelers. Thanks again, though.

I've got the coach up on the levelers right now so I don't think it's a good idea to play with the air bag settings. When I get a chance later this week, I'll lower it and maybe learn something.

Eric

[Bill Davis]

If it is indeed an air quick connect as it appears to be, it could be used for An air supply for your trailer, air brake assist for your toad brake system, and or, a place to connect a hose to air up your tires and air shocks. I’m assuming of course it has a onboard compressor. Didn’t Tinsman say that it did in an earlier post?

[eric1514]

Originally Posted by Bill Davis

If it is indeed an air quick connect as it appears to be, it could be used for An air supply for your trailer, air brake assist for your toad brake system, and or, a place to connect a hose to air up your tires and air shocks. I’m assuming of course it has a onboard compressor. Didn’t Tinsman say that it did in an earlier post?

It is almost certainly an air quick connect and because it is female, I assume it is for air out and not a place to insert air. Problem is, I’m 90% sure I don’t have an onboard compressor.

[RV Randy]

Go to Home Depot and buy a male quick disconnect air fitting and plug it in that female fitting at the rear. If pressurized air comes out you have onboard air. If it keeps coming out you should hear a compressor kick on, make sure the key is on and engine running. The previous owner may have installed a small electric compressor and hidden it well.

That rear air fitting could have been for toad air brakes or a place to plug in an air hose used to manually inflate the rear air bags, which are probably what the Schrader valves are for on the wheel wells.

[eric1514]

Originally Posted by RV Randy

Go to Home Depot and buy a male quick disconnect air fitting and plug it in that female fitting at the rear. If pressurized air comes out you have onboard air. If it keeps coming out you should hear a compressor kick on, make sure the key is on and engine running. The previous owner may have installed a small electric compressor and hidden it well.

That rear air fitting could have been for toad air brakes or a place to plug in an air hose used to manually inflate the rear air bags, which are probably what the Schrader valves are for on the wheel wells.

I plugged in a hose from my garage compressor but no air with the engine running. The fitting itself is in poor shape and would not connect properly to my hose. Perhaps that prevented it from flowing air. I’ve got some penetrating oil working on it to loosen it up but I don’t know where they would have hidden a compressor. This coach is on a E450 chassis so no air brakes.

[Bill Davis]

Originally Posted by eric1514

I plugged in a hose from my garage compressor but no air with the engine running. The fitting itself is in poor shape and would not connect properly to my hose. Perhaps that prevented it from flowing air. I’ve got some penetrating oil working on it to loosen it up but I don’t know where they would have hidden a compressor. This coach is on a E450 chassis so no air brakes.

Make sure you have the correct male fitting. As I recall there are 2 different configurations. The types I believe are Type A or IM, if memory serves.
Since you have a compressor in your garage you could pump air into the system at the quick connector and see where it ends up.

[eric1514]

Originally Posted by Bill Davis

Make sure you have the correct male fitting. As I recall there are 2 different configurations. The types I believe are Type A or IM, if memory serves.
Since you have a compressor in your garage you could pump air into the system at the quick connector and see where it ends up.

Pumping air into the system is a great idea! I've been unable so far to find the end of that 1/4" line attached to the air fitting. Maybe that will help.

[eric1514]

So, following Bill’s great suggestion, I blew air into that fitting at the rear and traced the hiss back to a compressor! It looks like a small Viair type with a small tank next to it. No I need to find out where the switch is for it.

Any ideas?

And thanks, everyone.
Eric

[Bill Davis]

Originally Posted by eric1514

So, following Bill’s great suggestion, I blew air into that fitting at the rear and traced the hiss back to a compressor! It looks like a small Viair type with a small tank next to it. No I need to find out where the switch is for it.

Any ideas?

And thanks, everyone.
Eric

I think your on your own there. Does it have a ride height sensor on the differential? It would look like a little box with a lever attached between the box and the axle housing. If it does it’s a automatic system. If not you need to trace the wiring off the compressor to the switch.

[eric1514]

It’s starting to look like there is no switch except for the pressure switch on the tank. With the key on, if you bleed off some air with the tank drain, the compressor kicks on until the tank is up to pressure.

That air fitting at the rear of the coach has seen better days. I’ll probably replace it with something from the hardware store. The plastic hose looks like it’s attached to the fitting with a 1/4” compression fitting. I’ll get a piece that’s 1/4” compression on one end and 1/4” NPT on the other and I should be good to go.

The system looks to be totally manual in operation. There’s a schrader valve in each rear wheel well and that’s it. No dump.

Any idea what the air pressure range is?

[eric1514]

Sigh...So I loosened the 1/4" air line at the rear fitting fully expecting a rush of air and nothing. I turned the drain on the tank and it's full and the compressor kicked back on, but no air out of the tank through the hose.

[Bill Davis]

Originally Posted by eric1514

Sigh...So I loosened the 1/4" air line at the rear fitting fully expecting a rush of air and nothing. I turned the drain on the tank and it's full and the compressor kicked back on, but no air out of the tank through the hose.

I had air tanks get rusty inside and clog up the fittings and hoses. Drain the tank and remove the lines and see if you can stick a coat hanger into the tank outlet fitting and clear it.

[eric1514]

Originally Posted by Bill Davis

I had air tanks get rusty inside and clog up the fittings and hoses. Drain the tank and remove the lines and see if you can stick a coat hanger into the tank outlet fitting and clear it.

That's a good idea. The previous owners neglected a lot of little things they didn't understand. I think I'm the first guy to turn the drain on that tank in 5 years. I'll disconnect the lines, too, and see if I can blow through them.

[eric1514]

Progress.

So the way this system seems to work is thusly. The air compressor makes air and fills the tank. The key needs to be on. The air in the tank exits into a small cylinder (1.5”x2.5”) that has two ports and an electric wire that taps into a positive somewhere. To one port on that cylinder is attached a plastic airline that runs aft to a coupler. The other port which exits out the top has a small metal line that runs back to a tee and then fore and aft. It is not air. It is the brake fluid for all four corners. The cylinder is in fact a switch.

So, the key must be on to produce air, but the engine must be on and the brake pedal depressed to release air. Really kinda dumb as it takes two people to inflate anything.

[RV Randy]

Since air is triggered by the brake switch, sounds like the system was used to operate air brakes on some type of towed vehicle. It's pretty unusual since most air operated toad brake systems just require a constant air source and the toad brakes are applied either electrically or by inertia.

If you T into the line between the tank and brake switch that should give you a constant source you can use to air up the suspension.

I have installed rear air bags on all of my F250/350s and typically maximum PSI on those systems is 100.

I told you there was probably a hidden compressor, nowadays they are pretty small and easy to hide.

[eric1514]

Originally Posted by RV Randy

Since air is triggered by the brake switch, sounds like the system was used to operate air brakes on some type of towed vehicle. It's pretty unusual since most air operated toad brake systems just require a constant air source and the toad brakes are applied either electrically or by inertia.

If you T into the line between the tank and brake switch that should give you a constant source you can use to air up the suspension.

I have installed rear air bags on all of my F250/350s and typically maximum PSI on those systems is 100.

I told you there was probably a hidden compressor, nowadays they are pretty small and easy to hide.

Yeah, that compressor is small. The tank it fills is probably 6" in diameter by a foot long, probably 1.5 gallon. It was all packaged behind the levelers and I thought it was part of that system.

If my wife is around to push on the brake pedal, it is adequate to fill the rear air bags. The tee is a good idea and pretty easily done. I put 60psi in them today, I'm just not sure why. It raised the rear some. Is the system for comfort or load leveling? Should I always run some air in them keep them in shape? This is all new to me.

TIA,
Eric

[RV Randy]

You can always eliminate the switch if you don't plan to use that setup. On the air bags I installed they say to keep a minimum of 10 psi in them. If you inflate them enough they will raise the rear up. They're intended to allow you to level it up if you load it heavy or add a lot of tongue weight with a heavy trailer, not so much to improve the ride.