[Archived]

Glen,

I am sure Hector will agree and what is unsaid, is that if your aux system pressure drops at some point your tag axle three port Norgren is going to dump air as it is supposed to. So the first question is “Does the bus maintain aux air pressure yet still lean?”

[glen]

My 1991 H3-40 does not dump the tags when the Aux drains down. Since I have changed my air bags and Norgrens it will stay aired up for at least a week. I don’t know how long yet cause that is as long as I have left it. My Aux tank however drains quickly as I have a leak in the Level Low valves up front i have yet to address.

[David]

Well Jon , got in from my office from west texas yesterday evening and the coach still had about 65 pounds on both gauges on dash from airing it up Monday before I left but left was down. It will drop over night now ( on right side now, was left side before) with plenty air on gauges. Drivers side was still at top height after 4 days. What’s funny about this is it didn’t start this overnight drop until I had ride height problem fixed a month ago. It would settle but would take a week or two to come down. That’s the reason I had bags replaced. On ticket they side bags had some small cracks and owner said replace. Which I did.

[Archived]

Well Tom you would think if you give these guys the go ahead and fix everything they would find problems. They have at least 50 hours chasing leaks. I have told them to replace everything under there if it needs to be.

[Roger]

Glen,

I am certain the gauges that read 65 PSI are brake systems. They have nothing to do with aux air pressure. If you want to see if the loss of aux air pressure makes the bus drop or lean in the rear, air it up and bring the bus to the drive height.

Then bleed aux air off and as it hits around 30 to 35 PSI you should see air escape and the tail of the coach to drop or one side to drop.

If that does not happen your coaxch may have had the system logic changed.

Try that and let us know what happens.

[Archived]

Glen,, Have they checked the Isri seat and the dash air guage connections for leaks?

[Archived]

Will bleed down and try, Jon. It’s not anything to effect running down the road. Loading up to take Granddaughter to the Gulf Coast this weekend. Have electric seating in this puppy no air. Have 2 gauges on dash and that’s what I’m looking at for pressure. This doesn’t have aux air compressor. Had the Prevost boys R&R windsheild wiper system also. Put new blades, pump and small hoses to wiper spray bar. They not wokie either. I think I’m haunted!

[needtocamp]

I’m really confused Glens, are you saying you have no aux air compressor and the only aux air you get is from the engine driven pump?

[Archived]

Truk Yes unless he modified it he probably only has Aux air coming from the engine. Glen I have replaced the air bags and even had Hector in my driveway with his magic bubble machine. We found many leaks and I fixed them. I now have the exact same problem as you. I can hold pressure for weeks on the dash gauges but as Jon says that is only your braking system and has no reflection on the suspension. What is happening is that we (You and I ) still have a leak somewhere in the Aux (suspension, door lock, generator bags, and etc.) that depletes the air in the Aux tank under the driver. When this happens the tags dump air but for some reason the right side drops lower than the left. Now I have squrited soap all over the right side rear bags and found no leaks. When it drops I can reach under the fenders and feel the air bags. When I do this the tags bags on each side are soft (deflated) the right drive axles bags are soft but the left side bags still have enough air to make them firm thus holding the left side rear up higher than the right. Have not found the answer for this problem yet but it is only a problem while parked. I have added a aux compressor a while back to keep the aux air tank full to prevent the tags from dropping. I do not leave this turned on because it will run down the chassis batteries if left on for a long time with out starting the engine. I have also added a trickle charger to the chassis batteries since experiencing the dead chassis batteries, but not know if it will keep the batteries up enough to run the aux air compressor for long periiod to prevent this problem.

I hope this helps a little.

Greg

[Rodger]

As Greg has pointed out our coaches are different.

One of the most difficult things to do as forum members is to be able to offer advice regarding problems another member is having. All of us offer advice from the perspective of how our coaches are equipped or based on the vintage coach we own. Owners seeking advice can help themselves and us immensely if they realize our advice is only as good as the information they provide.

While unusual in the sense most of our coaches have auxiliary air compressors, Glen’s coach does not have one and the lack of that information could lead someone to assume his aux air system was maintaining pressure and therefore the leans was due to a leak in the suspension. Another thing that made it difficult to offer good advice is the fact that as a percentage of coaches owned by our members, the number that have the system logic that dumps air when aux pressure drops is getting smaller so fewer owners are aware that could be a factor. The point is when owners ask questions they have to assume we do not know anything about their coach so either in their signature or in the post a detailed description is needed. As folks attempting to answer questions, we often need to spell out that our answer is based on assumptions, and we need to spell out the assumptions.

At this point apart from having some repairs to his repairs, Glen’s coach may be OK. His leans may be solely related to his suspension system logic which is the sme as Greg’s and if he wants to eliminate that issue he needs to work to make his coach “leak free” or do as Greg has and add an aux compressor.

As a final thought I think we are beginning to see a wider variety of house and chassic configurations as the bus and converter evolution continues making diagnoses more difficult. I can say the changes over the decades on my coaches are extensive and while the basics remain the changes to everything have been extensive. It is entirely possible the people servicing Glen’s coach may not even be aware his coach suspension logic causes it to dump air at low aux system pressures and that they are on a wild goose chase trying to find a problem that does not exist at Glen’s expense.

[Archived]

Sounds like if the tag logic is not going to get reversed and there is no aux compressor, just dump all the air each time you park and forget about it. It sounds like Glens doesn’t need any aux air when camping, so dump it all until your ready to go again.

The downside is when you fire it back up and get to ride height and the compressor continues to cycle, you’ll hear the purge valve often. You won’t know where your leaks are, but hopefully the primary and secondary brakes tanks will be stable. Without an aux gauge on the dash, you will have no idea how often your leaks are cycling the compressor while your driving.

I would add a 120 volt aux compressor, fix the leaks, add an aux gauge to the dash and maintain the entire system as leak free as possible. You can at least get the aux system to a point where it runs only a couple times a day if you install a compressor.

[needtocamp]

Tom is right.

If your converter did not add an aux compressor it is probable you have nothing in the house portion of the coach that uses air. The only problem with the lack of a compressor is (as you already know) you can forget about leveling the coach on sloped campsites. As soon as the air is gone the coach is leaning.

The good news is that the leaks are not likely to be in big numbers because you only have the Prevost chassis aux system to worry about. Also good news is you have a coach not likely to have push in fittings so the places to look are small in number. My guess is if you do a little checking in the common places such as the driver’s seat or air regulator (if you have OTR) you will probably find the biggest leaks.

Then when you do add a compressor so the coach will stay level you will rearely hear it run.

[Archived]

Don’t forget to check with soapy water the regular in the rear of the coach that controls the belt tightener for the coolant fan.

[Rick & Denise]

The push in fittings are always suspect to me. If you soap them wiggle them a little they might just start leaking. I’m not a big fan of them. Suppose to be latest and great! But I’m finding occasional leaking—- I’m changing mine back to old school for dependability. My opinion. easy check. Bob

[Archived]

I know Hector and I vote with Bob regarding the push in fittings.

Having said that I have them all over my 06 coach and at some point I am going to replace them with compression. The bad news is a considerable number of them are on manifolds that do not have enough spacing between them to turn 90 degree fittings so I either have to replace the manifolds or I have to go to straight fittings on the manifold and reroute some of the air lines to accomodate the change.

The 90 degree push in fittings swivel. Great idea, but I already had a leak at the swivel, and not where the air line went into the fitting.