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Need to Replace Hose(s) (And Fittings?)
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You are very welcome, Three of us.
Pull the cover off the Cut in-out switch the instructions should be on the inside.
If not e-mail me, I’ll get them to you.
AL
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Good question Jon, on reserve air pressure.
Here is my take on the increase pressure needed in the Marathon family. At some point Marathon developed a drop service door for access to electric cord ( Glendinning reel ) and sewer hose. This door is hinged to underside of bus body near the water bay, drivers side
Mega air is needed to extend and retract sewer hose. From the AUX reserve tank there is a dedicated 3/8 inch black supply air line, Another clear in color from a “Y” connector a few feet from the compressor. This supplys an instant air charge. These 2 lines run direct to rear reserve tank holding appox 5 gals. air supply. This tank sits behind the hot water heaters, passenger side.
The SMC air gauge is dialed at 80 psi..call for… setting behind drivers side bay door. The drop door does’nt need the 80 psi but the sewer hose action does.
Marathon was good at using different color hoses I found for techs and me to ID supply thoughout bus. It really helped in trouble shooting for air leaks to isolate a system and confirm which service was not a problem.
Two things happen when you press the button to get your sewer hose;
A) Button Labeled DROP…..Door drops down via an air cylinder much is like small cylinder used to operate the side windows in our buses. Only much larger in size.
B) Button Labeled EXTEND……Air is injected into the sewer hose but we must have a necessary cap attach to the end of hose to seal.
A knife switch opens to push a large volume of air into the hose and out it comes. The knife valve works in reverse to pull the hose back into storage.
To make this hose work smoothly the SMC gauge is set at 80 psi. Most often the demand of air triggers the AUX compressor cut in.
Prevost conversions are electric hogs, Marathon buses are also air hogs . The 120 lb. reserve air seems about right.
It’s a pretty neat sequence of events for rather dull activity to get your sewer hose in and out.
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< But you know how the heat impacted the life of the original hose. >
Yes, now that you’ve said that, I know. 🙂 I had been trying to figure out why the end near the compressor was so cracked and the end near the tank not at all. Had only thought as far as the check valve. 🙂
I’ve noticed, too, that the rubber belts that hold the windshield wiper fluid container (that’s what that large plastic container in the background of one of my pictures is, right?)…those little belts are also cracked. They are probably the original ones from 18 years ago though.
I should probably reassure you that my cluelessness re rubber belts does not extend to the ones on the engine. I watch them and have had them replaced and carry spare new ones.
Susan
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Jon, here’s what happened when I removed the hose from the compressor and tank.
I turned off the Air Compressor switches inside, in the switch box (Bass panel) and on the dashboard. When I removed the hoses from the compressor, no air shot out. But when I removed the other end from the tank, I “got surprised.” (nice way to putting it, Jon) I didn’t get dust in my eyes but I did get a bump above my eye when the check valve broke. I was pulling hard in an awkward position and when it released, I bumped against the front of the bus, complete with sound effects from the sudden release of air. It was actually very funny.
Regarding the bus, it did *seem* to go down to me but that might just have been my catastrophic expectation. When I looked at the Level Low bubble, it looked the same as before. As it still does today, two days later. I might be tempted to assume that this means that the leveling system is not leaking but I know it’s just because we are having hot weather. 🙁
The mud flaps are well off the ground. The sewer hose is fine, the same or almost the same height as before. (It comes out of the bottom of the coach and I use an adaptor, leaving precious little room.)
Should I draw the conclusion that the leveling system of my coach does have that ’90-something upgrade, where it doesn’t rely on the aux compressor constantly, Jon?
Or, put another way, what does it mean that the bus does not seem to have lowered itself down to the “bumps”?
Susan
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What you are talking about is tag logic. On the early buses, when the aux air got to a certain level, the tag would dump and lower the rear of the bus. My 94 Liberty had it and it would dump at about 45 psi. Your 96 , probably a 95 chassis doesn’t have it, so your good. As you have discovered, you can deplete all your aux air and the bus suspension shouldn’t move a hair. In fact, sounds like you don’t need aux air for anything while parked since you don’t have pocket doors or an air toilet. While parked, if you need to adjust your level low to remain level, that’s when you will need aux air and the more the better. Or, you can start the engine and build aux air in order to level.
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I didn’t see one of these. Maybe I just missed it…anyway, thanks for recommending that I let the air out first…I will make sure I install a release valve this time.
The reach into the fittings was awkward because the bumper extends out in front of the storage area, making it hard to reach things inside…especially for the likes of me, 5′ tall. My dad used to call me the mighty mite. I get a lot of, “You drive that bus?”
Susan
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Yay! I was hoping that I didn’t need the aux air while parked.
Except that I have had to use it in the cold weather, which causes a mild case of the leans. I believe it was Jon who turned me onto the fact that I can simply turn on the ignition, without firing up the coach each time (to avoid accumulating moisture in the engine) and the coach will re-level for driving.
I am going to fix the lean problem. As a first step, I wanted to make sure that the aux air and other easily accessed leaks are addressed.
Thanks, Tom. Susan
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Many thanks, Al, about not using tape. I am making a list of things to get on my next trip to Grainger and NAPA.
Susan
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Thank you, Al. I will see if I can get the cover off…3ofus
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Boy, Al, this list of possible leaks is a treat. I didn’t know about these places and am still in the dark about most of them, but will check into them for sure. Thanks so much.
Susan
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Susan,
FYI, there are check valves that are DOT rated. I replaced my check valve in the same location last year. The part was readily available at parts store dedicated to heavy trucks and construction equipment.
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What Tom said. If you lost aux air when the fitting broke and the mud flaps didn’t touch the ground in the rear you have the system logic that does not rely on aux air pressure to hold the coach up.
As far as the leans when cold, that is a preview of what is going to happen regardless of temperatures. Cold definitely shows leaks before you see them at warmer temperatures, but it doesn’t create them so at some point rather than worry about aux air pressures for leveling, start thinking about how you will address the leans because the problem will not be going away and will get worse. It’s the nature of the valves which are the most likely cause.
The good news is because you have the latest level low system logic you can isolate the cause of the leans to those few air bags and valves (and possibly fittings) and just fix what is leaking or you can begin thinking about replacing all the valves and air bags on the entire coach.
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FYI, there are check valves that are DOT rated. I replaced my check valve in the same location last year. The part was readily available at parts store dedicated to heavy trucks and construction equipment.
Good to know. I am in a small town so this NAPA probably doesn’t have as big an inventory as others…but I am going to Portland tomorrow and will have no difficulty finding one there. I will make sure about DOT rating. Thanks.
Susan
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Woo hoo! Good news.
Susan
PS Yes, you have given me that advice about solving the leans before, Jon. I am less green now and do understand this all the way now. Before I was hoping for some way out of the leans. But alas, the only way out is through. It will be fun now that I understand things better.
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We all are going to suffer the leans, some sooner than others, some later and I cannot see any consistency in when it happens. Some coaches 15 years old still don’t lean and never have, some don’t get 5 years old before they start having issues.
How any of us deals with them is an individual choice. Some replace air bags, valves, and all the push in fittings within the systems, other only isolate the problem and fix the source of the leak.
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