Tire Pressures Observation and Question

[Gerald Farris]

Mike,
If you leave the air leveling system on after it automatically levels your coach the compressor will automatically turn on and relevel the coach if it becomes unlevel. Therefore, if you are not turning the system off, the tanks deflate and the coach becomes unlevel, you leveling system compressor is not working.

However, you should remember that the leveling system compressor on your coach only runs when the leveling system needs air pressure and the air pressure in your tanks may still drop until the system tries to relevel the coach. At that time it will add pressure to the tanks until the coach is level and then turn off.   

Gerald   

[Jerry Emert]

Another consideration that may or may not occur to you...when i bought my coach I noticed that the air leveling system would not automatically keep the coach level as advertised.   I looked for and found the aux. compressor on the passenger side behind the front cap.  I was on the verge of replacing it when I remembered my extended warranty.  I brought it to be fixed just to get my money's worth.  It turned out to be the control board for the leveling system that was not sending the 12vdc to the compressor to activate it.  Turned out to be even more expensive than I thought so glad I brought it.  I guess my advice would be to make sure before you spend a couple hundred bucks on a new compressor and get all dirty replacing it!  Good luck.
Jerry
Jerry

[David T. Richelderfer]

Thanks Jerry.  You told me where my auxiliary compressor is.  A couple times when I returned to the coach there was a noise coming from behind the front cap, curb side.  It had to have been the auxiliary compressor.

I almost always turn on the auto air-leveling when parked, even for a little while like when stopped beside the highway for a break.  As soon as I take off the parking brake and put the transmission into gear the auto leveling kicks off and within a few seconds the coach has settled back into travelling mode.

Question for you more experienced owners:  Can the coach be leveled using the auto hydraulic-leveling, then be maintained subsequently using the auto air-leveling?  Will both systems operate together?  I realize the auto hydraulic-leveling does an air dump first, then proceeds to leveling.  But after that can the engine be started to re-pressurize the air tanks and then turn on the auto air-leveling.  I have wondered about the two auto leveling systems working concurrently.

[Jerry Emert]

David, my SMC era hydraulic system had been converted to manual operation so I can't answer that question .  Having said that, I think the two systems are independent of each other.  I never dump air before I level with the air leveling.  I start off with a pretty good step down after I level and a few days later my step is almost on the ground.  I rarely use the hydraulic.

[Mike Groves]

No luck yet on finding the 12V air compressor on my coach.  Is this the same one that runs when the engine is running or is it truly supplemental.  I don't think I have this device on my coach.  Gerald how sure are you that the 1999 Marquis has this device?  It's not mentioned in my owner's manual and like I said rather it says that air leveling is for short periods of time.  My system does have the automatic re-level at 30 minute periods and I have hear that operate but typically its a short expulsion of air. 

I did have some leaks corrected about 3 years ago after getting the coach but it is now draining pretty quickly so that if there is an aux compressor it should certainly step up and do something.  Nothing in the front of the front axle on the passenger side that I can see.  Mainly its the stair well sitting there.

Mike

[David T. Richelderfer]

As I tried to infer in my posting on this thread back on August 9, you should have an auxiliary air compressor since you have automatic air-leveling.  Why would anyone put auto leveling on a coach without giving the auto leveling mechanism the ability (read: a continuous air supply) to perform its function?

The auxiliary compressor only needs to operate when the engine is not running keeping the air system pressurized, and then it only needs to run when the air system gets down to some sensed low level due to leaks and/or usage by the various systems that operate using air pressure (horn, step cover, auto leveling,... whatever).

I have read several threads here on the Forum that talked about the original auxiliary compressor being a problem due to their installation location and lack of ability to withstand dirt and water.  In many of those threads it was determined the auxiliary compressor wasn't working at all.

[Jerry Emert]

No luck yet on finding the 12V air compressor on my coach.  Is this the same one that runs when the engine is running or is it truly supplemental.  I don't think I have this device on my coach.  Gerald how sure are you that the 1999 Marquis has this device?  It's not mentioned in my owner's manual and like I said rather it says that air leveling is for short periods of time.  My system does have the automatic re-level at 30 minute periods and I have hear that operate but typically its a short expulsion of air. 

I did have some leaks corrected about 3 years ago after getting the coach but it is now draining pretty quickly so that if there is an aux compressor it should certainly step up and do something.  Nothing in the front of the front axle on the passenger side that I can see.  Mainly its the stair well sitting there.

Mike

Mine is a 2003 and built by Monaco so they may be very different.  I can see mine right behind the cap as I slide my head under the MH on the passenger side between the generator and the backside of the steps.  Right up against the cap just above the bottom of the cap edge.
Good luck

[Joel Ashley]

Similarly to Jerry, I can see our compressor by looking underneath the passenger side in front of the entry step.  You may also find your slideout solenoid manifold/pump/tank unit up in there.  The compressor may be sitting atop a steel mounting plate that's bolted or welded to a frame member, and not immediately obvious.  Use a flashlight of course.  You should see an airline to help guide you to it, Mike, although there are airlines to the entry door bladder and perhaps other devices under there as well.

quote:   "My system does have the automatic re-level at 30 minute periods and I have hear that operate but typically its a short expulsion of air." 
This is your HWH computer checking every half hour for any off-level condition after auto-leveling.  The fact that you can hear it pretty much implies you have a working compressor under your right front corner somewhere.

Joel

[Gerald Farris]

David,
You air leveling system and your hydraulic leveling system operate totally independent of each other. Therefore, if you air level the coach, it can not use the hydraulic system to maintain level until you turn on the hydraulic system, and level the coach with it.

Mike,
If your coach was originally equipped with a HWH automatic air leveling system, it was equipped with a 12 volt electric compressor to supply air pressure to the leveling system when needed and it has nothing to do with the engine driven air compressor. If you do not have the air leveling system compressor now, it was removed by a previous owner.

The HWH air leveling system that was installed on the 99 Marquis was designed to exhaust air from the high side or end of the coach to level it as long as it possibility to level the coach without raising it above ride height. If exhausting air from the high side will not level the coach, it adds air to the to the low side and uses the 12 volt compressor as the source if the air tanks are depleted. Therefore, the 12 volt compressor only runs if the air system is trying to raise one point on the coach to level it.

Gerald   

[Mike Groves]

Gerald,

I'll take another look.  Can someone with a 1999 or 2000 take a picture of the location of theirs relative to some reference point that is easy to see...like a front tire, for example?

Mike