[Richard]

Dumb question. Do you have a tag axle?

Here is a sketch I made of Todd Flickema's setup.

Follow the lines for the concept.

   

Can you post a pic of your leveling valve switches? 

So my logic is a bit muddled, but one valve misbehaving is a valve problem. Two valves misbehaving, in a symmetric fashion, is a wiring flumox or a switch in the wrong position.

[Glenn and Laureen]

Tom and Richard thanks for your responses and for the sketch of the air system. A couple of quick answers:

1. We do not have a tag axle. Our coach is 35' 2" completed in January 1984. No tag, no slides.

2. None of the MAC valves seemed to be magnetized at any time when I was testing them (always in travel mode during the tests). Will do more checking on that tomorrow (Thursday). Should at least some of them be magnetized when the Level Up or Down switches are engaged? I would think so.

3. The coach does air up in either mode, achieves travel height, and each corner will raise really high in level mode. I was shocked at how high it can go. When the engine is turned off (and the compressor goes off with it), the air bags stay inflated but the supply air system PSI falls to zero within a few minutes according to the dash board gauge.

In addition, I will post pictures of the leveling switches (top and bottom views) tomorrow. The leveling switches have been in the off positions during all the above testing. I do suspect a possible wiring screw up in some way as a result of the mobile mechanic and then us replacing the ignition switch. We are tracing down the various wires and circuits going from the ignition switch to the leveling switches and the various MAC and Skinner valves. We found that one wire (brown) seems to go from the ignition switch to the rear six pack and another wire (orange) goes from the ignition switch to the front six pack. Both wires are energized with the ignition switch in the on position and, when energized, the top MAC valves (front and rear) start venting air.

Also, while looking around yesterday Laureen and I confirmed the location of our engine mounted compressor (the only one we have), found our air dryer and saw the purge valve discharge several times while the compressor was cycling. We also discovered another air tank, this one mounted vertically near the rear axle, driver's side. We also found our two rear height control arms. So, we are slowly getting familiar with the air system and have watched Richard's videos several times, which has been enormously helpful.

Tom, I went to Clarke's blog and found photos he had posted of his coach's rear six pack that y'all replaced and that was helpful, especially the idea of taking a picture of everything before starting to dismantle and replace anything.

[Richard]

“The coach does air up in either mode”. Would you define mode? Do you mean travel or level?

Good idea on checking which valves are energized.

Here are the very basics. In travel mode, with ignition on, the travel solenoids should be energized. No other.

In level mode, with no switches activated, no solenoids should be energized. If the raise/up switch is activated then the UP solenoids should be energized, And likewise for down.

The reason the airbags do not leak down with the supply pressure is that all solenoids (pathways to the airbags) are deenergized with the coach in off position.

Call me sometime when you are at the coach. 817 223 2056. Actually text me first, I get a lot of spam calls from Texas, and I don’t answer.

[Richard]

Sorry for SWAG questions.

There is an air line coming off the supply tee, that goes through a skinner valve feeding the big regulator. Where does the air line coming out of the regulator go? What does that regulated air line feed?

It appears that skinner valves have been added to the two DOWN Mac valves. I am trying to figure out why they are needed. Are the Down Mac valves still wired up? Are they wired in parallel with the skinners? I am just wondering if someone added the skinners to the Mac valves.

[jimg]

The skinner valves are normally closed valves to keep air from bleeding back thru the mac valves and skinner valves will only be energized when the ignition is on. The mac valves were good valves but leaked thru the valve all the time the N/C skinner valves eliminated the air leaks when not in use.

I would check all the wiring especially the grounds on all the valves. There is a ground connection at the bottom of the panel, but the one at the top isn't a good ground. All those grounds are daisy chained together and if you lose connection on one it could be effecting several valves. I would run the upper ground wires down to bolt to the lower ground stud.
Good luck!

[Glenn and Laureen]

Very helpful info, Jimg. Thank you. Our Skinners are off with the ignition off and are on (magnetized) when the ignition is on. Will check the ground situation the next time we go out to the coach. It was cold and rainy in Austin this afternoon so we did not get out there.

[Richard]

There is a clue here, just don’t know exactly how it could be happening. Jim, Clarke or Guy may be able to help.

First, if the purpose of the Skinnners is to provided a backup to the Mac valves leaking, then the Mac valves that the Skinnners are attached to are definitely the DOWN valves. If wired and functioning correctly the only time those Skinners should be magnetized is if the Down switch is activated.

Second, can one of the owners of this vintage coach explain the basic layout and function of the switches?
Specifically, is there a switch that toggles between level and travel?
Does the ignition on, override that switch and force the system into travel?
Is there an ALL down or ALL up switch for lowering and raising the coach?

Never mind my questions, I found the picture you posted when noodling the mystery switch in the drivers compartment.

Ok, cranking up my Conspriatron 5000, is it possible that the ignition switch rewire and this issue are related. Did you ever notice this before the switch issue? If not, is it possible that during the ignition switch wiring that you either wired something incorrectly in the powering of the leveling system OR something wasn’t working (like the mystery switch) because it didn’t have power and now it does.

[dkarb]

Deja vu.  After I bought the '87 I had leveling problems and they were caused by a few factors.  My problem may have been different than yours but maybe this will help.  I found the best way to deal with it is to make a diagram of your leveling system, label everything related to the valves and then in this order start diagnosing:

1. Make sure every single wire coming from the manual leveling switches in the front of the coach (mine are in the mid console) go to the valve they are supposed to go to.  Mine were not.  Also make a terminal in the back for the valve wires as it is much easier to work with/diagnose.
2. Make sure the main switch to go from auto level to manual level is the appropriate switch.  Mine was an off/on switch and it needs to be an either/or switch.  The auto level is normally on when the ignition is on unless you switch that switch to manual level.
3.  If there is still a problem it may be the leveling valves.  (It was with mine.  After fixing the other 2 problems we replaced both rear leveling valves and I have not had a leveling/air leak problem since.)  I was told these leveling valves get crud in them and there is a screen that gets plugged up and/or they just wear out.


These are some notes I made to myself (I knew nothing about this system at the time) and maybe they will help:

.The auto level airline from the auto valves goes to the front leveler valve and when auto wire is activated I think the front and the back auto leveler valves open.  Air goes out of the bags/tanks through the auto valves and out the hose to the front leveler and air is expelled from the leveler valve itself.  When the bus is down to where it should be the leveler valve shuts off and the air stops being expelled.  If the bus goes down below level, the leveling valve allows air back into the 6 pack (through the same air hose that the air comes out of the 6 pack to lower it) to raise the bus back up.  



.  One airline comes from the brake air tank and that is the supply air.  There is a pressure valve on the line from the brake air tank that turns off the flow if the brake air gets low.  The other air line at the leveler valve goes to the solenoid.  So when the auto solenoid for the L side is open, the manual L side solenoids are closed and the valve allows the air in from the brake tank to the auto solenoid to the air tank/bags L side to raise the L side until the driving level is reached then supply air is shut off.  If the L side is too high the L level valve will keep the supply shut off and allow air out of the bags through the open auto solenoid to the valve exhaust to lower the L side until driving level is reached.



I'm not sure how accurate the above statements are but that is what I understood at the time.




The photo shows my rear valves and my diagram of my air system which may not be exactly correct but it is to the best of my (small amount of) knowledge.

   
   

Hope I helped.

[Glenn and Laureen]

Richard and Dave, thanks for the input and Dave, thanks for your diagram and photo. Your diagram seems to match my general layout. I found it especially interesting to see that you have no MAC valves and only what I call Skinner valves. I think in my system the Skinner valves are used as one way valves in association with the 4 down valves and the air pressure regulator in the back 6 pack manifold.

Richard, that mystery switch near my leveling switches in my center console seems totally unrelated to the air system. I think it is related to an electromagnetic lock system that a previous owner installed on the access panel over my generator bay in the front of the coach. The wires are the same color (purple and yellow). It is supposed to be a push and release system but doesn't work right now.

Also Richard I am holding in reserve your invitation to give you a call until Laureen and I have actually tried a few things and can ask questions from a more informed position. We appreciate your offer very much.

After a month of beating this stuff to death and over analyzing everything, Laureen and I have a developed a few theories of what we can do next. We will start by replacing one down MAC valve in the next few days that we think has a significant leaking port. I anticipate a significant reduction in the air leaks after that. If so, we will replace the other 3 down MAC valves, which I think are also leaking to a lesser degree because of similar problems. Next we will replace a 5th MAC valve that has a definite air leak (bubbles) because of a leak in the casing (not a port). We may end up replacing all the MAC valves at once as they are not too expensive. I will post an update when we stop speculating and actually get something done.

[Richard]

At the risk of just restating the excellent input you have gotten from others, let me take a stab at what I would do in this situation.

Refurbishing the system with new valves is a worthwhile endeavor if you plan on keeping the coach. I would much rather work on stuff while I am at home, than in the middle of Wyoming.

I would take the approach of dividing the problem into two areas, electrical and solenoid valves.

The first thing I would do is ensure that the valves are wired correctly and the switches are doing what you think they should do. It’s a plain and simple exercise to have one person activate a switch and the other read the volt meter. Use a label maker and label the wires once you have confirmed they have power when they are supposed to. I like leads for the voltmeter with alligator clips on the end so I don’t have to fiddle with holding the leads on the wires. Also while going to this effort, check every pair for power when you activate each switch. It’s extra effort but you will protect yourself from unexpected wiring anomalies.

Only after confirming proper electrical function would I replace the MAC valves. The skinner valves are a band aid I think, and I would think very hard about using the MAC valve and skinner valve in series. You need one or the other, not both.

When I wired the new MAC valves in, I would use the watertight butt connectors, and hit them with the heat gun to seal them up.

Make a map of the system to add to your coach documentation.