So attached is a picture of the air gauges after they have bled down. This is after 3 days. As you can see the pressure is just around the 30 to 40 mark. Should I be concerned? Is there a fix I have not researched to fix this?
My guess would be, if they drop below 60 there's a check valve that's not doing it's job. Mine do occasionally but fortunately not very often.
My coach also drop to 30 psi after a couple of days and Eventually will go to 0 PSI And that is normal it is almost impossible to get a system airtight You can read in the Owners manual and it will give you how much air that you will probably lose and it's in hours not days
It maybe be air tight new but not for long and I say maybe if your lucky
Rick answered your question. I wish mine had 30lb left in 3 days but I'm thru looking for the air seeps, What's important is when you apply the foot brake the air doesn't keep escaping after the initial fill of the brake chambers which takes about 5 to 10 lbs each application. It is rare for a coach to not seep down just sitting. See one every now and then but it won't likely last and Isn't important.
Static Air Loss,
"The loss rate should be no more than 2 psi in one minute for single vehicles"
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The proper procedures for inspecting the air brake system are as follows:
Test Air Leakage Rate (Static check)
With a fully-charged air system (typically 120 psi), turn off the engine, chock the wheels, release (push in) the parking brake button (all vehicles) and trailer air supply button (for combination vehicles) and time the air pressure drop. After the initial pressure drop, the loss rate should be no more than 2 psi in one minute for single vehicles and no more than 3 psi in one minute for combination vehicles.
Test Air Brake System for Leaks
With parking brake, (all vehicles) and trailer air supply button (for combination vehicles) released (pushed in), apply firm pressure to the service brake pedal. Watch the air supply gauge and listen for leaks. After the initial pressure drop, the loss rate for single vehicles should be no more than 3 psi in one minute and no more than 4 psi in one minute for combination vehicles. If the air loss rate exceeds these figures, have the air system repaired before operating.
Test Low Pressure Warning Alarm and/or Signal
Turn the key to the on position. Rapidly apply and release the service brake pedal to reduce air tank pressure. The low air pressure warning signal must come on before the pressure drops to less than 60 psi in the air tank. If the warning alarm/signal doesn't work, you could be losing air pressure without knowing it. This could cause the spring brakes to activate suddenly. Only limited braking can be done before the spring brakes come on.
Check That the Spring Brakes Come on Automatically.
Continue to rapidly apply and release the service brake pedal to further reduce air tank pressure. The trailer air supply button (if it is a combination vehicle) and parking brake button should pop out when the air pressure falls to the manufacturer's specification (usually between 20 to 40 psi). This causes the spring brakes to come on.
Check Rate of Air Pressure Buildup
When the engine is operating at 1800 RPM, the pressure should build from 85 to 100 psi within 45 seconds in dual air systems. (If the vehicle has larger than minimum air tanks, the buildup time can be longer and still be safe. Check the manufacturer's specifications.) If air pressure does not build up fast enough, your pressure may drop too low during driving, requiring an emergency stop. Don't drive until you get the problem fixed.
Test Service Brakes
Wait for normal air pressure, release the parking brake and trailer air supply button(for combination vehicles), move the vehicle forward slowly (about 5 mph), and apply the brakes firmly using the brake pedal. Note any vehicle "pulling" to one side, unusual feel, or delayed stopping action. This test may show you problems which you otherwise wouldn't know about until you needed the brakes on the road.
Source: 49CFR383.113
Copied and pasted from here: CDL Pre-Trip Inspection: Brake Check | CDL Digest (https://cdldigest.com/cdl-pre-trip-inspection-brake-check/)
Your protection valves are weak if it stays at the pressure in your pictures. If it keeps dropping the next day they are failing. I read lots of posts that you cannot worry about the air leaks, just as posts say the dash air will never work. I have my coach leaks down to holding over 100psi for 3 days. Case in point last week the DW and I went to dinner after 4 days at the campground and upon returning when I hit the remote to lock my car the Hadley's went off and kept blowing. After realizing that the remote could not be causing it, I looked in the window of the coach and one of the dogs was standing on the steering wheel watching us. My crane only used air for brakes and I have it holding 120 psi. for weeks. Air leaks can be stopped just not something most people want to put the effort into. As mentioned before there is no need to stop the small leaks but it can be done.
You May need to be the next one that gets under mine for air seeps Chuck.. I'll be much obliged and will carry water for ya.
Ok. Where are the protection valves located and are they an easy swap out I am not sure where to get them here in Canada either but I suspect a heavy truck shop or such?
The Protection Valves are located above the front axle near the front and rear dry air tanks are located. They look similar to a miniature propane regulator because they have an adjustment screw/spring. Mine were leaking such that the air leak could be heard standing beside the coach. Once under the coach I could feel the air blasting out the hole for the adjustment screw. The way mine air hoses are plumbed, I would have had to dismantle and reassemble several pieces to replace the protection valves, so I disassembled the protection valves and replaced the seal rubber surface with a cut down piece of a bicycle repair patch. The release pressure increased to 70psi (was 60psi). In the eleven years I have owned my coach I have done this repair twice.
You should be able to get them at a truck shop
I'll bring mine over and we'll "let" Chuck make a day of it - he can do a "two fer one special". I'll bring something stronger to mix with the H2O.
Search for "protection valve" using the Forum search tool. Order results by "most recent". You will find some good info.