Aux Air Leak??

When I arrived at my current destination I manually leveled the coach before turning it off. After turning off the bus I went outside so that Pam could extend the slide out. This process requires that we unlock the key which is an Aux Air driven device. All worked fine, and the slide went out without a hitch.

I then heard what sounded like air leaking from the steering bay, opened it to hear air escaping from a small red plastic valve release or over pressure device (see attached image).

When I placed my finger over the opening, bottom red plastic valve, adjustable to some degree, attached to a small black square box which has a black air line coming in the air stops, but after a few seconds the 75psi blow off valve blows off the excess air pressure. I thought that all that was happening was that I had a few extra pounds of air in the system and it was bleeding off until it reached the correct pressure. I decided to wait until the next morning to check.

I have checked the pressure and there is none in the aux air side which can be isolated by a valve for the slide out and pocket doors etc. I filled it back up and it is leaking back out at the same point, the little red plastic valve at the bottom of the row of 5. There are 6 lines, 2 black lines at the top, red green and yellow and black at the bottom underneath, its the black line at the bottom that leads back to a Norgren valve a few inches away.The leak is at the little red screw valve at the bottom black box.

Question: Is there a simple fix or do I need to replace the valve, as I call it, ie. the little black box with the red plastic pressure screw on it???

Thanks.

Bruce

Hi Bruce. Those are your solonoid valves, essentially your interface between your electrical system and your air system. Jon would know if they can be fixed, in a pinch you could swap one for another like your slide out floor.

Bruce there is in all likelihood a way to mechanically cycle the solenoid valve, such as pushing the piston/spool/valve with a tool such as a small screwdriver. You can shuttle it back and forth, to loosen and or displace a small piece of dirt or alleviate a "sticking of the valve".
I know this works on hydraulic valves, and should work on air.
If you get it to work, let this be your first warning and get yourself a replacement to carry for the next time it happens, as it surely will!
These solenoid valves are an excellent candidate for the spare parts to be carried on the bus.

Quote:

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Originally Posted by garyde

Hi Bruce. Those are your solonoid valves, essentially your interface between your electrical system and your air system. Jon would know if they can be fixed, in a pinch you could swap one for another like your slide out floor.

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Thanks Gary for the quick response. Your answer opens up some new questions that I will have to better understand I guess, including where each line goes to, seats doors slide etc. I will give it a go. Still wonder why this happened all of a sudden.

I have been having some intermittent IRSI (Pice of sh..) seat problems with one line that comes off. I had all line connections replaced , but they missed one. Slide locks work great, pocket doors and bed lift, I need to stop the leak some how. The odd thing is when I have the pressure at 75lbs and place my finger over the solenoid that is leaking the pressure over flow valve blows off in about 5 seconds or so, can't figure this out.

I am clearly challenged in this area and will need a crash course.

Thanks.

Quote:

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Originally Posted by JIM CHALOUPKA

Bruce there is in all likelihood a way to mechanically cycle the solenoid valve, such as pushing the piston/spool/valve with a tool such as a small screwdriver. You can shuttle it back and forth, to loosen and or displace a small piece of dirt or alleviate a "sticking of the valve".
I know this works on hydraulic valves, and should work on air.
If you get it to work, let this be your first warning and get yourself a replacement to carry for the next time it happens, as it surely will!
These solenoid valves are an excellent candidate for the spare parts to be carried on the bus.

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Jim , good idea and I will try this, but you have just said something about spare parts. Marathon created a spare parts box for me, will check it out and see what I have in the goodie bag.

If I find one, how do you replace it?? Do they come apart separately?? I am going to check for one now.

Thanks

Bruce, Your photo shows the manifold valves (solenoids) that control your leveling system. They do fail but can normally be repaired.

Before doing that however, suggest that you re-level the bus then return the leveling system to the road position and immediately turn off the ignition key to prevent the bus from returning to road height. This seems to neutralize the valves in the off position and prevents leakdown. I'm sure Jon will be able to explain why. Adding one of these valves along with some O rings to your spares kit is a good idea.

To inspect/repair the solenoid, dump your leveling system to zero then remove the spring clip under the red screw. This will allow you to slide the solenoid magnet from the valve body and making 4 phillips screws accessible. Using a #1 phillips screwdriver, remove the 2 long machine screws from the valve body and remove it from the manifold. There are a large and small O ring on the bottom of the body which should be replaced. While you have it in your hand, remove the other two flat head screws from the body and carefully separate the two halves. You will find a spring and valve seat, inspect the rubber valve surface for nicks, dirt or uneven wear, if the seat is damaged replace the valve body.

I just took some pics of the disassembly process but noticed Jim C and Gary have chipped in. Will have the photos on line in a few minutes.

Sorry about the focus, Dale will be ashamed of me.

Some have a single small screw in the center of the electrical "plug" on one end (the part with the wires)

Loosen the screw and wiggle off the plug.

Examine the valve body to discern the way in which it is mechanically mounted to the switch block, and loosen that mounting. (save all screws, as they will be needed for remounting the new valve)

Swing the old valve, still attached to the air, out of the way and mount the new valve to the switch block.

Remove the airline and fitting from the old valve. Install the existing line and fitting to the new valve. (best to have the air off), but could be done in a pinch with air in system (work quickly).

Brian, your camera needs cataract surgery.:D:eek::D

Bruce,

The attached link will provide log on information to the Suspension Presentation that Jon and I gave at Seiverville this year. It should help with the basic features of the suspension. I am sure your particular coach converter added its modifications. The presentation was based on a prevost drawing for my version of coach, 1995.

If Jim Skiff reads this message, please get in touch with me to coordinate providing a link to this presentation directly from this site for easy access by POG members.


http://forum.prevostownersgroup.com/...ead.php?t=2116


Good luck,

Hector

Thanks Brian,

This might explain why I noticed the noise right after doing a manual leveling of the bus.

When I finish the leveling I leave the switch in the last position I had leveled.

Before I restart the bus I move it back to the ride position, have I done something wrong in this process ,should I leave it in the ride position after I turn off the key??

I will look for your picks and read the other posts. I definitely am not level any longer, will get back.

Thanks Brian, very helpful, I will use this as guide, but after I test with a restart of the ride position key on..

Quote:

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Originally Posted by JIM CHALOUPKA

Some have a single small screw in the center of the electrical "plug" on one end (the part with the wires)

Loosen the screw and wiggle off the plug.

Examine the valve body to discern the way in which it is mechanically mounted to the switch block, and loosen that mounting. (save all screws, as they will be needed for remounting the new valve)

Swing the old valve, still attached to the air, out of the way and mount the new valve to the switch block.

Remove the airline and fitting from the old valve. Install the existing line and fitting to the new valve. (best to have the air off), but could be done in a pinch with air in system (work quickly).

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Jim I will follow your suggestions but after I get a replacement part. PS> there is no way that I will be able to do this quickly as all projects are on the job training sessions for me.

Also when I restart the bus am I going to be able to return to normal ride level position?? Is this solenoid that vital a a part to the operation of the bus over the road????

Bruce, As I mentioned, am not sure why this works but returning the switches to the ride position immediately before shutting off the ignition switch locks the valves in the ride position where they're less likely to leak. The system is deactivated when the ignition switch is off so you can leave the switches in the ride position. The bus will then go to ride height when you make your next startup. At least, that's the way it works on our Liberty

I did the re-leveling and the quick shutdown in the road position, and the solenoid is still leaking.

I guess when I finished leveling I left the position switch in the left side position when I turned off the key, this may have contributed to the problem.

I will take the little bugger apart and see if I can clear its little brain.

Thanks,

Bruce

The solenoids are the coil to which the wires are attached. By energizing the wires the coil becomes a magnet and the magnetic force puills the valve open.

When the coil is de-energized the valve spring closes the valve. When the valve is closed the air pressure in the line that pushes the Norgren valve pneumatic operator is released and spring pressure in the Norgren valve pushes the Norgren valve to its normal position.

The reason I point this out is that there are several failure modes. The most likely is the valve itself leaks at the base. There are two screws (in some cases they are phillips and in others they are #10 torqs. They are under the coil and to access them pull the coil by removing the "c" ring. Tighten them. If that does not do it, remove the valve itself and see if the small "O" ring has been pushed out of place by air pressure.

You will have to do a little detective work to find the offending valve body but if it is a problem isolating the actual leak to a specific body try tightening all of them.

If they are all tight and if you do not find an "O" ring out of place then it is likely the valve itself is leaking. They can be ordered from Prevost and in your hands overnight. If you cannot live without your aux air you may have to go to Lowe's or Home Depot and plug or cap the aux air line feeding the manifold. That line to cap is the one going into the bottom of the manifold. That will allow all other aux air systems to be aired up. Until that leak is fixed and the aux air line to the manifold restored however you cannot travel. If this valve assembly leak is sufficiently large or is associated with a solenoid that affects the ride height you could have problems if you try to drive.

If you must move the coach before you repair the valve the valve that must be working perfectly is the center one in the stack. Make sure that valve is not leaking by swapping it if is is the bad one with any other. Just do not swap coils from their original positions. The center valve in your stack is the one that controls the valving to bring the ride height valves into play.

Quote:

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Originally Posted by Jon Wehrenberg

The solenoids are the coil to which the wires are attached. By energizing the wires the coil becomes a magnet and the magnetic force puills the valve open.

When the coil is de-energized the valve spring closes the valve. When the valve is closed the air pressure in the line that pushes the Norgren valve pneumatic operator is released and spring pressure in the Norgren valve pushes the Norgren valve to its normal position.

The reason I point this out is that there are several failure modes. The most likely is the valve itself leaks at the base. There are two screws (in some cases they are phillips and in others they are #10 torqs. They are under the coil and to access them pull the coil by removing the "c" ring. Tighten them. If that does not do it, remove the valve itself and see if the small "O" ring has been pushed out of place by air pressure.

You will have to do a little detective work to find the offending valve body but if it is a problem isolating the actual leak to a specific body try tightening all of them.

If they are all tight and if you do not find an "O" ring out of place then it is likely the valve itself is leaking. They can be ordered from Prevost and in your hands overnight. If you cannot live without your aux air you may have to go to Lowe's or Home Depot and plug or cap the aux air line feeding the manifold. That line to cap is the one going into the bottom of the manifold. That will allow all other aux air systems to be aired up. Until that leak is fixed and the aux air line to the manifold restored however you cannot travel. If this valve assembly leak is sufficiently large or is associated with a solenoid that affects the ride height you could have problems if you try to drive.

If you must move the coach before you repair the valve the valve that must be working perfectly is the center one in the stack. Make sure that valve is not leaking by swapping it if is is the bad one with any other. Just do not swap coils from their original positions. The center valve in your stack is the one that controls the valving to bring the ride height valves into play.

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Hi Jon,

The solenoid that appears to be leaking is the bottom one, and it appears to be leaking from the red plastic portion right at the little opening on one side of it at the corner of the red plastic screw, it looks like a relief valve of some type, if I place my finger over the end of the red screw and hold it there for a few seconds it will blow off the over flow valve near the norgren, and makes a sound like it has reached its maximum capacity, this of course happens after I refill the air system, otherwise it has completely run out of aux air.

I am guessing by your description that valve is not closing. It sounds like it is bad. As stated before Prevost sells the kit to replace the valve. it consists of the valve body and all that is necessary is to remove the defective one and replace it. Two screws and a "C" ring and that's all that is required to be removed and the valve body comes off the manifold.

The new valve will have a new "O" ring to go under it, replace the two screws, put on the coil and the "C" ring and your problem should be solved.

If the converter did not modify the system that should be the valve that controls the left rear. If the leak is not too bad you can drive the coach, but be aware you will be working your compressor to keep up with the leak.

Quote:

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Originally Posted by Jon Wehrenberg

I am guessing by your description that valve is not closing. It sounds like it is bad. As stated before Prevost sells the kit to replace the valve. it consists of the valve body and all that is necessary is to remove the defective one and replace it. Two screws and a "C" ring and that's all that is required to be removed and the valve body comes off the manifold.

The new valve will have a new "O" ring to go under it, replace the two screws, put on the coil and the "C" ring and your problem should be solved.

If the converter did not modify the system that should be the valve that controls the left rear. If the leak is not too bad you can drive the coach, but be aware you will be working your compressor to keep up with the leak.

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I have successfully repaired the solenoid thanks to all of you. This only proves that it is possible to walk the mechanically challenged through problems successfully.

Here is how I handled it: I first took off the clip, removed the first half then removed the flat and torc screws. The large "O" ring had some kind of crap on it that clearly would open the seal. I took the entire solenoid apart, cleaned each "O" ring including the area where it rests, removed the spring inspected it, cleaned its ends and replaced all parts, pressurized the system and all is good.

PS: all O rings looked as good as new, but the end of the spring near the magnet was very dirty and needed cleaning.

Thanks again.

Bruce,

Your funky o-rings may be a sign of water/oil in the aux air system that got mixed up with dust and dirt. Make sure you frequently drain the air tanks, service the dryer filter and drain any water out of the small black cannister in the steering bay (assuming you have one). Also, if you have a aux compressor with it's own tank, make sure you drain that one often, I get a little moisture out of mine everytime I drain it and I do it often.

Quote:

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Originally Posted by truk4u

Bruce,

Your funky o-rings may be a sign of water/oil in the aux air system that got mixed up with dust and dirt. Make sure you frequently drain the air tanks, service the dryer filter and drain any water out of the small black cannister in the steering bay (assuming you have one). Also, if you have a aux compressor with it's own tank, make sure you drain that one often, I get a little moisture out of mine everytime I drain it and I do it often.

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I had just drained the tanks, replaced the dryer filter in the steering bay, but I agree the O Ring did look a little funky and the end of the spring, the magnet end looked like it had some oily film on it at the contact point, but otherwise the O rings looked like new, just some crap on on one edge of the large O Ring. Glad to know how to repair this now and what it does in the first place. After about ten years I might, just might have a handle on these important items.

Congrats on getting it fixed! POG comes through, again!

Quote:

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Originally Posted by Ray Davis

Congrats on getting it fixed! POG comes through, again!

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The mechanically challenged comes through again. I have convinced a prevost owner who I met to join POG, should be happening soon, great guy lives in Stuart Fl., Paul Might know him.

Bruce,

Great job taking care of that pesky leak!

One of the great benefits of POG is being able to take advantage of the collective knowledge and experience of the members.

I had the opportunity to share the benefits of POG with my neighbor at the Lunenburg Ns campground while I was in the process of following the direction from Brian, Jon and others. I showed him the thread and exactly what I was doing. I think Steve will join POG soon.

I now plan to get a few spares and slowly take apart and clean each solenoid after I get the spares.

Its really important to have good spares onboard. I have enough fan belts and fuses and light bulbs to go into business, but not everything I need for sure.