Leveling Incosistencies

[aggies09]

I am trying to understand the way that my "automatic" leveling system operates. During a recent trip I noticed that each time I tried to level the coach by hitting my "auto" switch, I would get a different result. Should this system be a reliable feature for leveling the coach? If so, what and where should I look to better diagnose what is happening to me?:confused:

[Jon Wehrenberg]

Tony,

Maybe someone more knowledgable about the nuances of the Liberty leveling can offer some specific service information, but I have found that the automatic leveling feature is something that gets you in the ball park but lacks the ability to be precise and apply logic.

Regarding the logic, whenever possible I want the front down as low as possible, so if I manually level the coach I drop the front end and then make whatever adjustments are necessary to level it. When the front end is high the step height is not an easy one, even with our little portable platform.

The second deficiency is accuracy. It does a good job of getting the coach close, but if we need it perfect I have to manually adjust it to get it perfect on occasion. I believe the control for automatic leveling is a pendulum whose pivoting end actuates switches which in turn actuate the solenoid valves. Even if the adjustment is perfect there will be some variation due to tolerances in switch repeatability. If your bus is consistently out of level in the exact same direction every time, I would guess that could be adjusted to be more accurate, but inconsistencies are likely as the result of tolerances.

[truk4u]

Jon,

Any idea where the leveling devise is located in the Liberty?

[phorner]

On the Liberty coaches that I have seen, there is a small box suspended from the top of the first pass through bay behind the front door. There should be a warning label on the box that says that the gyro is enclosed and to be careful around it.

However, in "Auto level" mode, my bus seldom is actually level..... I always end up fine-tuning it manually.

[aggies09]

Maybe I was expecting too much from this feature it appears that everyone has to make adjustments after auto leveling. Jon gave me his procedure for leveling. Is that the procedure that most of you use when leveling or do you have alternate methods. Jon's system sounds very logical and should work provided that you are on somewhat level ground to begin with. I was in a park in Liberty Hill, TX this past weekend that I am not sure anything would have worked well.

[jimshoen]

Go to the store (Home Depot, lowes, Ace, etc.) and buy a good quality Torpedo Level. Set it on your counter top near your Range. Get that counter top level and the rest of the bus is perfect.

[garyde]

I use manual most of the time. Between wanting the front to be low as Jon has said and getting the back to be lower so the shower will drain properly, it is a challenge. I do use the Auto also, but endup adjusting manually most of the time.

[Jon Wehrenberg]

The automatic leveling feature is great for showing off. It is neat to hit the automatic switch and then get out of the bus and stand amongst the other camp ground residents watching your bus level itself.

But even though the automatic feature is OK most of the time for an overnight or even to have lunch in a rest area, if we are staying in a campground for a few days we level it manually. We can criticize the automatic feature for its lack of precision, but I use it a lot and I really appreciate the ease of use for stops of short duration.

The "brains" is in a box located on the ceiling of the first bay, but the Liberty specific portions of the system includes their switches which differ from the Prevost switches which allow simultaneous operation of the functions on all three positions. The Prevost system only allows raising or lowering one position at a time.

Liberty adds two solenoid operated Norgren three port valves in the steer compartment to complete their modifications. These valves are part of the rear systems.

[ddeluco]

I Realy Enjoyed All The Input On The Auto Level System,I Have Trouble All The Time And Haven't quite Figured It Out Yet,
Good Stuff!

David

2002 Lady Liberty / HUMMER H-2 FOR FUN

[Jon Wehrenberg]

David,

It couldn't be simpler......When you are parking move the switch from the "road" position to the "auto" position. The coach will level itself. The key must be on and you should be running the engine to assure that you have an air supply available.

When the coach is level, the air is locked in the air bags when you turn off the key. If you wish, prior to turning off the key put the switch back into the "road" position and then immediately turn off the key. If you wish to level the coach manually, put the switch in the "manual" position and move the front, left rear or right rear up or down as required using the three switches for that operation. When the coach is level, return the three switches to the off position and turn off the key.

Easy.

[jack14r]

My 08 Liberty uses a leveling system from Spectron Systems Technology Inc. called a Threshold angle detector.It will adjust the bus to a .3 degree in pitch and a .5 degree for roll.Just last week I used a Starrett Precision Level and adjusted the coach and now it is very level with the auto system but that does not mean that the front is as low as I might want.

[Jon Wehrenberg]

I can see it now. Instead of a Bling contest in OKC we are going to have a level contest.

Instead of a Starrett Precision Level in my coach I use the shower door. If it stays open where I put it, the coach is level. I used to use a marble. If it rolled the coach wasn't level, but I am trying to cut down on stuff I carry.

[rfoster]

If you had a Country Coach, you could just hit the level button and forget it. I use one of my grand kids building blocks on the counter top and it has never rolled off.

[Gary & Peggy Stevens]

I used to use a marble. If it rolled the coach wasn't level, but I am trying to cut down on stuff I carry.

So Jon, you are leaving your marbles at Home ? :D I guess that is better than loosing your marbles, you at least know where you left them. :p

Gary S.

[Jon Wehrenberg]

Marble........singular. I'm a minimalist.

[ddeluco]

Jon,

Thanks for the info,we are taking a trip in April and will set it up your way.

Thanks again

David


2002 Lady Liberty / H-2 Hummer for fun:)

[rahangman]

Maybe Jon can help me with my 90 Country Coach . My coach does not have the 4 switch arrangement I see you talking about. Mine has a dial with Drive,Port,Foward,Starboard. Next to it is a seperate Rocker Switch UP or Down. When I park and go to manually level using the Level Low the only direction (up or down) that works is Down ! It will not come up! I have to return the main dial to Road and of course it brings the entire bus up ok. Of course when going down to Port, Starboard remains or seems to go up. Same with Starboard. Forward of course just goes down. The older HWH Auto Leveling works on leveling but is just not getting it to "LEVEL" and shows excessive grade in what should really be no mean feat. Lots of work has been done $$$ , Prevost said Level Low is working as intended (yet does not go up) and HWH was spellbound

[Jon Wehrenberg]

Hangman.......As I said previously there have been many suspension system variations over the years made by Prevost, and adding to the confusion is the number of converter installed modifications such as your HWH system.

I do not have a clue (remember that) how CC added the HWH feature. So from here on I am speculating.

When you place your selector knob in the drive position one of your solenoid valves should open and that will result in air pressure being applied to three five port Norgren valves, shifting the internal spool so a path is open from your ride height valves to the air bags. From your description that part of the system is functioning. From that I can conclude one of the four solenoid valves on the rear bulkhead in the lower steering compartment is funtioning.

For your investigation you need to determine which one is the ride height valve. Have someone switch the knob from any position to the drive position until you have isolated which valve is the one. Your vintage coach should have 4 valves on a manifold. Look for the red buttons.

The remaining three valves relate to the raising or lowering of the coach to level it when you are not driving. Again, switch the selector to any other position except drive, and press the up/down rocker switch. Listen for and identify which valve is clicking. Since you say you can make the bus go down, but not up in any position my guess is the fault lies with the up/down switch.

I do not know if you have a multi tester or if you are mechanically inclined. If you have the tester and some basic skills you can forget about sticking your ear next to small solenoid valves to hear if they click, and instead just test the switch. If the switch actually tests OK (and there are no loose terminals) the next step is to check for voltage at the solenoid coils when you actuate the switch. Assuming you get voltage, check to make sure the solenoid coils are not "open".

With all three positions failing to raise the bus this points strongly at the up down switch as your starting point. I doubt if three solenoids would all fail simultaneously and that all three manaual positions on the selector knob would fail to pass current.

The photo below shows the solenoid valves. You should have four, not five as shown.

[rahangman]

These solenoid valves are new, having been replaced last fall as part of the resurrection of the system. My Multi-Tester expertise is minimal but I do know how to use it. With these instructions, I believe I can isolate this problem and will let you know. Been a long time since I have been mechanically challenged but I am up for it. Thanks again.

[Jon Wehrenberg]

Start at that up/down switch. When you get to checking the solenoids (doubtful if they are the issue if they were recently replaced) just try to learn via your ears or multitester which solenoid are energized for each command from the leveling system controls. Record that information because the next time you have to trouble shoot you will not have to check everything.

I can tell you what each of the 5 solenoids on my coach control, but it is completely different than your 4.

This is an extremely long shot and not likely to be the problem, but Prevost has shipped the wrong air bags on several coaches. They would come up to ride height, but not beyond. There were some posts regarding this. Your explaination seemed to indicate that the "Up" command would not even bring the coach up to that level so that is likely not a consideration.

[gmcbuffalo]

Anyone know the functions of each port on the 4 solenoid manifold?
I tried to listen and feel while the wife moved the switches, didn't help.
GregM

[Joe Cannarozzi]

I know Jon does but he is currently soliciting pilots.

I think the 2nd one down is the drive mode.

If you unscrew and pull the plugs on them one at a time it will tell you.

[dreamchasers]

Greg,

My coach uses 5 separate solenoids on the level low system (I hope that is what you are referring to). With your Prevost coach number and the prevostcar website, you can get a pneumatic drawing that is representative of you pneumatic system (This is how I sorted out my leaks). With the pneumatic drawing that pertains to your coach, the solenoids should be shown.

To see how a five solenoid level low system function, see below.

Log on to:
http://www.dreamchasers.us/pog/pres

User: sevierville
Password: airbags

all small letters.



Hector

[truk4u]

Greg,

If you are talking about the 5 port, another way to identify the "road position" valve is to leave the key on a few minutes and the valve will get very warm to the touch. If it is the 5 port, I think "road" is the middle one or
3rd down.

[gmcbuffalo]

I have a 1991 XL and it only has 4 ports instead of 5. If you look at the Prevostcar webste and plug in your numbers it seem that you can not get any old info designs. For example try to get info on an 8V92 or a four speed transmission by telling them you have a 1991 MTH 40 XL. Doesn't happen for me.

That is why I ask if anyone knows the function of the ports.

I will start with the temp trick and then move to dissconnecting the wires after that.

Thanks.

GregM

[gmcbuffalo]

I have examined my four port solinoid manifolds and the order of function is the same as solinoids 2-5 the five port. 1-Front, 2-Drive, 3, Right rear, 4-Left rear. The function of the add 1st solinoid was done by a 3 port Norgren just below the Solinoid manifold.

GregM

[Joe Cannarozzi]

Good post Greg good info. IMO here is a good addition to the spares bin.