[JIM]

How loud is it ? can you hear it running?

[Bob]

Nice job… That would make a nice replacement if my Thomas awning compressor ever quits.

[Paul]

Nice compressor find and installation in existing space.

Question, Have you mounted a check valve somewhere close ?

AL

[Rick]

Both the Thomas and the Viair compressors come with a check valve in the air line.

Regarding noise, I mounted the new compressor on a piece of 1/2 inch plastic cutting board so I could reuse the original mounting holes and rubber isolation in the steering compartment floor. This provides double vibration isolation. Overall the acoustic noise is about the same, maybe slightly less.

[Peter]

Since the primary use for that specific compressor is to make cars with those air suspensions jump up and down are we to expect when you pull into the next rally we are going to see the bus doing the same?

[AL]

I could probably crank up the footwell air slide and bathroom door to 120 psi. That should cause some excitement.

[Archived]

One of our members accidently hit the floor slide button when he was on one of the bottom steps going into the coach. The floor slide came out so fast it knocked him out of the coach and unconscious. At 120 PSI it probably would have knocked him into the next county.

[Archived]

Finished up the AUX compressor replacement and a needed upgrade adding a water seperator today. This should give me some advantage in being able to just look inside the drivers bay to check for moisture in system.

Bus built back in 2000, water from compressor operation had only one place to go, AUX air tank. That tank was replaced last year.

Ordered water seperator with filter and simple bottom twist drain valve. Intake air filter is advertised being quieter. I ordered one and it is.

Old AUX 3 gallon tank.

Mounted above drivers side steer axle it contained about a gallon of water. Drain was plugged up and after taking inspection cover off some where along its life was simply drained in place. What a mess

New pancake tank found at Grainger.

[Archived]

I
took it one step further and eliminated the small compressor, isn’t
needed. The main aux compressor in the gen compartment supplies my
Marathon air tank and all accessories. When I’m ready to go, I turn
the yellow valve to charge the Prevost aux air (inflating the engine
air bellows) then shut it back off, the engine compressor takes over
from there.

Mine
came from the factory with the big main aux compressor and a small
Thomas for the Marathon side that provides air for pocket doors,
seat, gen air bags, floor slide and passenger foot rest. While in
Coburg last year we determined the Thomas compressor was not working
and Leon agreed it wasn’t necessary, just bypass it and use the main
aux compressor.

Yours
may be setup different…

[Archived]

Two comments……..if you install a check valve it has to be located far enough away from the compressor so heat does not impact its performance. The rubber seats don’t handle heat well unless rated for high temps.

That pancake air tank would scare me. First, it is the type used on cheap Harbor Freight compressors so I would be concerned about its life span. A replacement air tank should be DOT quality. Thicker materials and designed to hold the pressures in the bus systems. If a tank is going to fail, it could be due to corrosion of the thinnner tank metal, but a greater concern would be the pressure cycles that lead to fatigue.

For home use our compressor tanks will not see the number of high to low to high pressure cycles in a year that the same tank could see in a few days on a bus. It is hard to believe but the constant cycling of our engine driven and aux compressors is working to fatugue the metal in our aux tanks and personally I would not put anything in the bus air system that is not DOT.

[Archived]

Tom,

Is that true for all Prevost – that a smaller compressor is not required? If so, is it standard equipment or added later? Also, is the Main or smaller compressor used to air up the tires? Any maintenance required on the compressor?

[Archived]

Almost all conversions have an auxiliary compressor powered off the house circuits and used as Tom mentioned for things such as pocket doors, generator air bags, bed lift, etc.

Two compressors seems to be a Marathon way of doing it and is not typical.

Usually the aux compressors have cut in and cut out pressures lower than the pressures provided by the engine driven air compressor. If you need to air up tires, even if the aux compressor pressures are high enough you should run the engine because to air up a tire you not only need high pressures, you likely also need a large flow of air that aux compressors are not going to have.

[joel]

Jon,

When I was looking for a tank to replace our rusty one the pancake tank from Grainger was what was in the bus

Same specs but not rated DOT. The one in service 14 years on the bus installed by Marathon was not rated DOT.

New check valve installed which I forgot to mention was a 400 degree rated Viton seal from Valve Check, Inc.

St.Paul Minn. Triple the price of one available from Grainger.

Tom,

It appears our set up is differant then yours. I do not share the Prevost air system with AUX leaving that valve closed.

My project today is to polish all the brass fittings before reinstalling compressor. It’s a Marathon thing.

---

1999 XLV X-6872,  liberty #440

[Bernie]

The last trip we were on last month made it evident I have at least one new air leak, and likely more. It has been creeping up on me and I have started to address the leaks. I completely replumbed the converter manifold with a new manifold, all compression fittings and all new ball valves.

One manifold on the Prevost side is shut off with a solenoid valve when the key is off. The second manifold on the Prevost side is not shut off so I have two systems to start checking. The Marathon way of isolating the house systems from the bus aux system is a good idea because there is nothing I need on the bus aux system when I am parked. But since my coach is plumbed to use the Prevost aux air tank for the house I still have to use that tank because I do not have a dedicated house tank as described above. Marathon gets a high five for doing that.

Because I can shut off the valves to the house air systems I already know I cut my aux compressor run time in half. That means I have as much leakage on the Prevost side as I do on the house side. Further, there is not a single house system that is an obvious big leaker so to chase my leaks, house and chassis I literally have to start at the respective manifolds to see which are the biggest leakers and to start with them.

I would rather eat bees than chase air leaks but at 10 years of age my coach is telling me it is time.

[Archived]

The Godfather jumped in and brings up a real good point on someone looking for a used Marathon. The aux tank and the way the system is plumbed is a good idea but if the Marathon aux air is neglected by the previous owner you can look forward to doing what BA and Truk have done.

As far as I know the only thing that builds water in the system is the compressor cycling. The more leaks you have the more it runs and more water. People don’t check or drain it enough and before you know it the inside of the tanks are shot.

When doing a PDI on a bus, check the air systems, how long will it hold air.

Better yet fix your air leaks and you won’t have to worry about it.

Leak free is a constant battle.

Later

bv