Page 2 of 2 FirstFirst 12
Results 11 to 20 of 20

Thread: Aux Air Pressure?

  1. #11
    Join Date
    Mar 2013
    Location
    Chicago
    Posts
    3,988

    Default

    Your line thats leaking is the one that is COMMING FROM the side of the ride height valve in that rear corner as the photo Gill posted. Not to or from the front. There should be 2 valves there side by side. Whatever valve it is attatched to thats the corrisponding rear corner the line comes from.

    With the correct supports in place the tires do not even need to be removed thats less than an hours work and about 20 bucks in plastic 3/8 line and fittings. The fitting at the ride hwight valve end is 1/4 pipe to 3/8 compression. The fitting at the valve is 3/8 pipe to 3/8 compression

    The other line coming IN the bottom of that norgren spool valve is COMING from the norgrin air manifold under the drivers area it produces air or lets it out when u hit the up and down button at the drivers seat or when Iin auto level. The top line is GOING to the air bag.

    The 2 smaller black 1/4 in lines on the ends r the signal lines. One is energized when in driving mode the other is energized when u r in level low manually setting height or when the cc auto level is turned on.



    When u turn the key off neither signal is present. If the valve is completly air tight u can pull every line out of that valve accept the top one going to the air bag and that valve should maintain pressure to that perticular corner of the suspension. Thats actually the way to bench test those norgrens right on the bus.
    Last edited by Joe Camper; 11-16-2014 at 09:58 AM.

  2. #12
    Join Date
    May 2012
    Location
    Beverly Hills
    Posts
    4,652

    Default

    Joe is pretty much king of the Prevost air systems, so little doubt in questioning what he says.

    The Prevost air system is thought by many to be the most complex sub system on the bus. IMHO, that's only because there isn't a good description stating the logic and controls. There is a drawing available from Prevost. And as good as it is, it's still hard to fully understand what you're looking at. As just one example of something missing from that drawing for the XL is the check valves. Not knowing where these are makes it that much difficult to fully understand the logic. Even the self proclaimed experts have stumbled and provided misinformation. These are people that pride themselves in doing most everything on their own coaches and having replaced every Norgren air control valve on the bus.

    I spent some time with a Prevost Service manager that really knows his stuff. When we tried to dig into the details of the air system we used both the air drawing and the illustrated parts breakdown. What we discovered were both the answers and more questions. The questions came from differences from the two illustrations. Air lines were not run from the same places, in a few instances. Once the logic is understood, it becomes apparent that both drawings achieved the same goals and exactly the same functionality even though the air lines were ran from different places.

    What I can tell you from the drawings and your description are two Norgren valves that are 5-port valves located where you describe, is that they are Level Low control valves. And as Joe stated they have air lines to the air bags and the 5 port electric/air solenoid manifold in the lower bay under the driver's location. They control the air flow to the suspension based on whether the level low is engaged or the ride height control valves are engaged. CC uses the HWH controller for automatic levelling when parked and it simply takes over the functionality of the level low control switches that are located below the driver's window or hidden in the electrical bay just below the driver's window. I know that the blue air line would be specific to the suspension system. What I couldn't tell you is which line is on which port without looking at it or assuming the diagram has the Norgren valves illustrated in the as installed.

    Let us know how the repair goes. If the failure was due to chaffing, all of us XL owners should take a look at this hose.


    Gil and Durlene
    2003 H-3 Hoffman Conversion

  3. #13
    Join Date
    Sep 2009
    Location
    Houston
    Posts
    240

    Default

    Thank you for all of the great guidance.
    On this one, I am going to see where I go with it by myself but have a mechanic standing by just in case. The explanation is a relief.
    The help is truly, greatly appreciated.
    I will keep you posted.

    I owe you guys some Cajun Chicken Spaghetti or at least some true Texas Bar BQ. On that subject on a lighter note, I just noted in my Wall Street Journal of yesterday that a fellow wrote an article on Bar B Q in Austin, Texas. He stated that when he picked up the brisket...it literally fell off of the bone....

    Q: What is wrong with that statement?
    A: Brisket is a combination of two muscles and does not have a bone....

    I wonder if the guys in NYC will catch that one?

    Pres

  4. #14
    Join Date
    Nov 2006
    Location
    Huntsville
    Posts
    3,135

    Default

    We did have some excellent diagrams/schematics on here that Hector had developed. I don't know why they are still not in the Articles section? I think it was deleted because the link was no longer active.
    Hopefully, we can get Hector to re-post the information. He is also very knowledgeable or the air system.
    Dale & Paulette

    "God Loves you and has a plan for your life!

  5. #15
    Join Date
    Sep 2009
    Location
    Houston
    Posts
    240

    Default

    I found the hoses and the ride height adjustment valves to which they are connected. One cannot tell which hoses go where because of the harness...... until they can be disassembled from the harness and followed as to their direction.

    I have decided this is beyond my risk profile and do not want to be under the coach without professional assistance and supervision. Therefore, we have elected to fully support the coach with appropriate coach supports and two 20M# jacks. We will then pull the driver's side duel tires off to gain complete access to the offending hoses. From this, we will hopefully be able to tell the actual hoses with the holes in them and which of the ride height valves they service. I can definitely see that this is a job that is perfunctory but the circumstance of being under this thing bothers me. I am leaving this to the professional.

    Thanks again to everyone....
    Pres

  6. #16
    Join Date
    Sep 2009
    Location
    Houston
    Posts
    240

    Default

    Tonight, the mechanic and I determined the line that is leaking is indeed one of the lines that goes up from a canister type of object and through a rubber "boot" and then goes forward through the bays toward the air compressor. It is leaking at exactly the rubber boot. The leak is not the blue line I first thought was leaking. We looked in the next bay forward on both sides of the coach to find where the boot goes.... On the passenger's side, we have the bank of batteries but can see what appears to be the hoses coming from the rubber boot and going across the top of the bay toward the front of the coach. You have to be about 3 feet 7"" and weight about 50 lbs to be able to reach them...There may be only a very slight chance we could determine which hose is the one leaking and pull it back and cut it in the battery bay. If so, we would put a "quick connect on the front end and replace the entire hose going back through the wall and the boot to its point of beginning.
    Any thoughts on this? ... I assume these hoses would be very hard to pull through for any distance.
    As a question...how does anyone replace one of these hoses completely at all if they fail like this?
    All the mechanic kept saying while he was under the coach was "whew!"...
    Sorry to bother you guys but this one has us stumped. We can't get to these hoses. Thoughts would be appreciated....greatly.
    Very best,
    Pres

  7. #17
    Join Date
    Mar 2013
    Location
    Chicago
    Posts
    3,988

    Default

    If u r story is still the leak is present when u go into driving mode and stops when u go into leveling mode

    AND

    u r reasonably sure it is in the location of


    the rear spool valves

    AND

    it is not the blue 3/8 plastic line between the norgren and the ride height valve

    THEN

    The only other line energized in drive mode in that location would be the black 1/4 in signal line going to that norgren.

  8. #18
    Join Date
    May 2012
    Location
    Beverly Hills
    Posts
    4,652

    Default

    Reagan,

    Ideally you could pull enough hose so you could put a coupler on the forward direction line and a short replacement line to the Norgren air valve. The reality may be that this is not possible.

    It is not uncommon to abandoned-in-place wiring and plumbing lines that are simply too difficult to remove. Instead, a new line is ran. Before you can run a new line you need to know where the two end points of the line you're wanting to replace. In your case, there are two 1/4" black lines running forward and only one needs to be replaced; which one is the question. The two lines both run to the bay under the driver's window. Most of the lines run to the electric solenoid controlled Norgren that has 5 electric solenoids. Let's number these solenoid controlled ports 1 through 5 with 5 being the one closest to the end of the manifold that has a hose connection. If the rear Norgren that has the leaking hose is on the driver's side then the two hoses go to the port 3 of the forward Norgren (the one with a T fitting) and the port 5, closest to the end with an end connection. If the rear Norgren with the leaking hose is on the passenger side then one of the two hoses go port 4. The other hose goes to one of the air only Norgrens next to the electric solenoid operated Norgren. These 2 valves are identical with one having 3 connections used and the other having 4 connections used. The one with 4 connections should have a T fitting. One of the hoses on that T fitting goes to the other like Norgren and the other goes to the rear passenger side Norgren.

    Okay, now with that you know where the other end of the hose can be, it's time to identify which on of the 2 it is. Simply disconnect both of the hoses up front and blow air through them, 40psi should be more than enough.. One will have that air existing the leak.

    Now simply run a hose the most convenient and protected route from front to rear. My guess is that path will be through the center overhead of the first bay and possibly the second bay. It will then come into the third bay, battery side, and be routed along the ceiling of that bay. I'm guessing you can penetrate the rear wall in a location that will allow you to feed the hose through and keep it away from the wheel well area and any other area that looks like it could be subject to road debris. As an alternative, it might be possible to bring the line down into the generator bay and exit the bottom where it could be run along side the steel member that protects the generator exhaust. If you take this route, and it's not preferred, run the hose inside a piece of electrical conduit and use fasteners every 12" to mount the conduit to the metal support opposite side of the exhaust.

    Okay, let's say you don't want to make the new run. The battery box can be removed. I would really not want to take it out given the level effort of removing the batteries, inverters, and all connections, but it is possible.

    Good luck,


    Gil and Durlene
    2003 H-3 Hoffman Conversion

  9. #19
    Join Date
    Sep 2009
    Location
    Houston
    Posts
    240

    Default

    Gentlemen, especially Gil, Joe and another of my new heroes....Hector....
    After all of your superb guidance, we determined we could not access the hose anywhere beyond the forward wall against the battery bay and the leak was actually directly in the collecting boot going through the wall. We were able to pull about 4 inches of the 1/4" tubing back into the drive axle area. We attached a "brass in-line quick-connect" to a fresh 1/4" air line and then tried to get the older airline into the other end of the "quick-connect"....it was a task because we literally could not reach it. We took two long handled pliers and gently grabbed the old end with one set and the fitting with the other and forced them together untouched by human hands.... We felt the fitting was very secure and that the integrity of the air line was sufficient to hold. Then, we connected the new line to the valve using new fittings. As always, you don't know until the final test. After pulling and stressing the connection, we built up the pressure and turned on the key. SUCCESS!. NO LEAKS!
    The reason this was so important was that if we could not attach to the remaining end...there was literally no choice but to have to run a complete line from front to back with all that involves.

    Joe, I appreciate your careful explanations and Gil, as always, you gave great, thorough guidance. HECTOR...I can only say thank you for all of your efforts and for taking the initiative of providing me with the coach's complete schematics and other information. What a super team effort.

    The leak was actually a "flake" out of the skin of the hose itself. It was not greater than a 1/64th" spot. The line wasn't broken and was not "penetrated" by any object. It gave way where the tie down had a grip on it.

    Thanks again to all and I hope anyone reading this enjoys the information and might be able to avoid similar issues in the future or at least solve any issues more easily.

    The list for the Cajun Chicken Spaghetti is growing.

    Best,
    Pres

  10. #20
    Join Date
    May 2012
    Location
    Beverly Hills
    Posts
    4,652

    Default

    Great news Reagan.

    I wonder which air drawing Hector gave you. The one found on the Prevost site under pneumatic drawing section has too much on it for its size to be used for real troubleshooting. It is good, but it would be much better if it was drawn to a much larger scale with more details. There are more detailed drawings in the parts breakdown. In the parts breakdown there is a much more detailed drawing solely on the level low suspension lines and components. Even with its detail, it doesn't have everything. As an example, it illustrates the rear ride height valves but not the check valves on the ride height valves..

    As much as I'd like more details in some of Prevost drawings I won't complain. I think we should all be thankful we have access to this level of detail.


    Gil and Durlene
    2003 H-3 Hoffman Conversion

Similar Threads

  1. Why use a pressure washer?
    By sawdust_128 in forum MISCELLANEOUS ITEMS
    Replies: 5
    Last Post: 11-26-2009, 05:08 PM
  2. Air Pressure Regulator
    By phorner in forum On The Level
    Replies: 3
    Last Post: 10-29-2009, 02:16 PM
  3. Oil Pressure range
    By aggies09 in forum Engines, transmissions, axles and wheels
    Replies: 9
    Last Post: 07-19-2009, 05:56 PM
  4. Pressure Pro Wanted
    By BrianE in forum PARTS AND PIECES FOR SALE OR TRADE
    Replies: 1
    Last Post: 01-13-2009, 01:41 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •