Air Pressure Questions

[Dick Simonis]

Ok, I've been doing some playing around trying to understand how the air system works, if I have any leaks, and etc.

Yesterday, I aired up the suspension using my garage compressor to 110 psi without retracting the jacks and let it set overnight.  By this afternoon, the green needle was at 0 psi and the yellow at 40 psi.  What was interesting is that the front suspension was back sitting on the jack but the rear is still at ride height.

So, I suspect there is a leak somewhere in either the front suspension or brake lines.  It looks like the front and the rear are isolated but that there must be some kind of a pressure regulator between the two tank, which allows both to fill from a single source, but doesn't let the one tank (yellow) completely loose pressure if the green tank does.

This also suggests that it doesn't take much pressure to fully inflate the air bags....seems that it reached ride height by the time I got to 60 psi or so.  Is this a valid observation???  If it is, could one soften the ride by reducing the air pressure on the bags??

Regarding air leaks, how long should it hold pressure in a static condition??

If anyone can shed addtional light on our air system, it would be greatfully recieved.  I been trying to find a plumbing diagram for a Magnum Chassis without any success.

[Dave Blystone]

i dont have a layout for the airlines  but i do have a 2001 patriot and my air will stay up for 3 0r 4 days and it never looses all air
 if you get a layout send it to me please  
  dave and edie
2001 patriot 33
cat 330
 curly5420@aol.com

[Dick Simonis]

Yeh, I figure I have a leak and hoping it's not to tough to locate and repair.

Finding info in the air system is't very easy but when I crawl under I'll try and identify and document the major items, lines, and etc.   Perhaps I can post a simplified plumping schematic.

Anyone know if there are any items in paricular that are prone to leak?

[Robert Mathis]

Do you have a separate 12v air compressor for your air suspension system? I had several leaks in my suspension system, most of which were around the compressor itself, and the pressure switch. The other one was in the rear over the tag axle, and was a bear to get to to ifx. The best method to find the leaks is a plastic spray bottle with some soapy water. The leaks will bubble.

[Dick Simonis]

No seperate compressor on this model.  One on the engine that suppiles two tanks and pressurizes everything else.  Wrapping my head around how everything connects is causing me some grief so I guess I just need to crawl around with a pad and paper and start diagraming.  And yes, start spraying soapy water to see what blows bubbles.

[Marty and Suzie Schenck]

There are two sets of 2 air tanks, one set in front between the frame rails and one set in the back near the hydraulic  fluid tank on the right side. Mine did the same thing and I found out it was one of the front electric air dump valves leaking ever so slowly. I took the valve off and put some air tool oil in it and cycled it with a 12 volt battery. I put it back on and it now holds air again. Marty

[215]

I found an air leak in the step cover air valve and had to replace it.  Luckily it is located in the side bay electrical compartment easily accessible.  So there seems to be no easy answer for tacking down a leak.

[Dick Simonis]

Thanks for the info.  Never thought about the step cover so I'll take a look at that also.

Regarding the dump valve(s):  I take it from you comments there is a valve for each axle.  I assumed that there would be one valve that dumped all the air.

While we're on the topic, what is that beeping sound that we get when the suspension airs up and also when it dumps.  Kind of a steady tone at low(er) pressures and beeps faster as the air increases.  The converse is true when dumping.

[Marty and Suzie Schenck]

On mine there are 4 dump valve solenoids, one for each corner. The beeping noise could be the audible tone for the low air pressure gauge (should be on at about 0-60psi) or the warning for a leveling jack leg that is in the extended position. Marty