My latest problem

[John316]

I wonder if anybody has any ideas for me. Our coach (DL3) leans when not running. It doesn't instantly lose pressure, just slowly overnight. It then leans to the right. I have checked the usual. Leveling valve – brand new and I even replaced the check valve again to make sure that it wasn't a lemon valve – ,all airbags – brand new –, and I replaced a fitting on the manual un-loaders, that was leaking a tiny bit. I have also sprayed down a lot of the fittings (with soapy water) for the leveling system. I am out of ideas. Is there any bases that I haven't covered? Could it be the fitting on top of the airbag? Am I missing something really obvious? Also, our whole system bleeds down overnight. Which is really strange, because not too long ago it would hold air for quite a while. We didn't do any major work, and I don't hear any leaks?!?! I think that we have a phantom leak (that is all too real...LOL).   

Any help would be great!!!

God bless,

John

[PP]

Interesting, mine does exactly the same thing and it's a Prevost. Always dips to the right, never the left All new bags, no noticeable leaks. I can't wait to hear the replies here  I've installed a 2gal AC for when we're parked to keep the level low working, but when I leave it off, overnight it will sag to the right.  :(Will

[Blacksheep]

Well not sure if this helps or not but regarding prevost, you might find an extra air bag on the rear duals. On mine there are actually two of them. One of themis hidden inside a compartment that has what I call a trap door right in front of the tags. I didn't know this air bag was in there until a fellow bus nut had his replaced. Not sure if all are like this but it may be something to look for. A hidden air bag!

Ace

[buswarrior]

With religious perseverance the spray bottle with the soapy water is your route.

With new parts, lots of focus on the connections and the exhausts of the valving.

For the "whole system", do you mean the gauges on the dashboard?

If so, that's the brakes leaking somewhere, or a failed pressure protection valve letting it out your other mystery leak. Do you see zero or somewhere up at 60 lbs in the morning?

I'd be very suspicious of the brake treadle valve, and the relay valve down the back.

Get a soap bubble over the exhausts on these and see if it grows.

A leak free coach is possible, especially a post airbeam, post rad shutters, MCI DL3!!!

Keep working at it, you'll get there!

happy coaching!
buswarrior

[PP]

Ace,
I thought that was for lifting the tags But maybe I'm looking too far toward the rear. From all the soapy water I've used under this thing, it's gotta be the cleanest rig from the ground side up 
Thank you and I'm Sorry for stepping into your thread John. Good luck and keep us posted, Will

[Blacksheep]

PP an air bag is an air bag regardless of what it is intended use is, it still holds air! My point was that it is hidden from view where the other ones you can see from looking in front of or behind the tires. These you cannot see unless you remove the tire and remove the access panel on mine anyway!

Ace

[Hobie]

Isn't it great to know your bus is a Republican!!   harrr

[PP]

Okay Ace, I'll bite. You really got me curious. All the times I've crawled around under this thing, I've never seen em. So tomorrow, if the freezing rain and snow abates, I'm going back under. At the least, I should be able to see their hiding place. Thanks again, Will

[Blacksheep]

Well like I said, I have a hidden air bag that I didn't even know was there on my H model. Not sure what or how others are built! Yours may be different!

Ace

[Sojourner]

Here are things we all must remember:
After all the air leaks are fixed....the automatic air leveler still need the air supply from tank or optional electric compressor to maintain it adjusted level. Why? Because the coach is floating on air. Every time the coach is senses movement while stand still or traveling, it will either exhaust or add air to maintain that adjusted leveling valve linkage. In other words, every time while standing still and whenever the wind is blowing onto coach or getting in & out of coach or just walking around inside of coach will cause the needs of a supply air pressure to maintain it adjusted height. Also if you are park so that one side is lower by 2 inch or more will cause the high side to be more sensitive to bleed and add air.

So every time someone here on the posts about how long it hold air...it all depend on which of the factors of the above paragraph and how big your bus's air reserve tank if it park and no air pumping in the mean time unless you have auxiliary electric air compressor on board.

So the "How long it holds air?" quotes mean nothing to the bus nut.

BTW....the only way to locking air pressure in air bag such as tires do is to added a 3 points leveling system to by pass automatic levelers. Remember air temperature will control air pressure variable....just the tires pressure change from cold to warm to hot.

Our bus nut Pete/RTS Daytona (left click) (a retired IBM System Engineer) has a system available

Or you can make your own system.

BTW...all coach manufacture's air levelers are 3 points system design to minimize uneven coach's body stresses. MCI's are rear 2 leveler control side tilling and 1 front leveler control the fore & aft tilling only. The other front leveler is for kneeling only. So avoid the 4 points version that is available.

FWIW

Sojourn for Christ, Gerald

[makemineatwostroke]

Gerald;if all manufactures use a 3 point leveling system how does the low level system work on the H-45 VIP Prevost a friend of mine has one it goes down then levels on each corner and I noticed a J 4500 in Vegas did the same 
have a great evening

[pvcces]

Gerald, our 4106 uses leveling valves that have a delay of 6 seconds before they pass air. This avoids any air in or out of the bags in any period less than the lean from a normal curve in the road.

As I understand it, no air should be required to keep the coach up if there are no leaks.

Do you know if or which models of bus do not use this kind of delay? I would expect the delays to be used on all coaches for just the reasons that you mentioned.

For what it's worth.

Tom Caffrey

[John316]

Thanks for the info. It looks like I am back to the old spray bottle. So it doesn't look like I missed anything that I should have seen (besides hosing all of the fittings down). If I have missed something, let me know. I won't be out there today, windchill of -3...and snow. Oh, well.

BTW, the "whole system" means our gauges on our dash. Our duel tanks (well there is four, but it has a primary and secondary tank) bleed down over night, with out being able to hear anything. I will check the brake relay, and treadle.

PP, I don't mind you asking your related question on this thread. If it helps you, ask away .

Thanks for your help.

God bless,

John

[Sojourner]

Gerald;if all manufactures use a 3 point leveling system

They do.

how does the low level system work on the H-45 VIP Prevost a friend of mine has one it goes down then levels on each corner and I noticed a J 4500 in Vegas did the same 
have a great evening

If it all four corner...that new news for me. If it is, then it has dual leveling system at all 3 points. It can be a newer electronic design "dual or multiple" leveling valve all in one unit. ? ? I haven't seen one yet but nothing is impossible. However, I see no need to remotely lower all 3 points from the manufacture point unless motorhome customer want it equips with independent control lift system for parking on un-leveled ground.

The bottom-line a four points system is unethical. It will prestress the coach body for no good reason and you can only lift so much so that both front and rear wheels has equal pair of surface contact pressure.

FWIW

Sojourn for Christ, Gerald

[Sojourner]

Gerald, our 4106 uses leveling valves that have a delay of 6 seconds before they pass air. This avoids any air in or out of the bags in any period less than the lean from a normal curve in the road.

As I understand it, no air should be required to keep the coach up if there are no leaks.

Do you know if or which models of bus do not use this kind of delay? I would expect the delays to be used on all coaches for just the reasons that you mentioned.

For what it's worth.

Tom Caffrey

Yes, that is correct. All mechanical leveler use Silicone fluid to delay the changes. However, anytime anyone in the coach that moves from front to rear or from side to other is usually more than 6 seconds. And minimum wind at whatever speed alone of 6 seconds or longer, will take air. And if it was repaired with the wrong oil or no oil, then it less than OEM time setting.

I should have added to my first post (I am sorry), to service all three leveling valve after all the leaks are fix.

Thank you for bring the 6 seconds delay.

FWIW

Sojourn for Christ, Gerald