[Harry]

There is a check valve at/on the regulator for belt tension, this is to help maintain air pressure on belt biscuits. If the biscuits, regulator or the three way aren’t leaking. all of this is located just under the oil reserve tank

Glenn

[Archived]

Hello, I carry a small Makita compressor. I air up the bus before starting and I also use it to keep the air bags inflated. The Makita compressor shuts off at 140 psi, this is more than enough to air the bus and cycle the air dryer. There is a fitting in the rear of the bus that can be use to air up the bus. I tried couple of versions from Makita and the low rpm compressor is much quieter. This was a nice addition to the bus.

Bandsaw

[Bob]

I am not sure of the question. It suggests your Marathon lacks an aux compressor when I thought they all came with one. What Marathon does that is different from other conversions is with their aux air compressor and system there is a provision to isolate it from the coach accessory system via a valve. If the valve is opened the aux compressor should supply air pressure to the Prevost accessory system which provides air to the belt tensioners.

[Harry]

Busnut,

I to have had belts come off at start up, good advice about the check valve, just make sure you are leak free at the air bags, fittings, etc. down stream.

I had a 97 Marathon and it had an aux compressor from the factory.

[Archived]

thanks for the feed back

if my coach has or had a aux compressor where would it mounted ? i thought i have opened every compartment door and panels with screws etc… i have replaced most of the N valves all of the airbags ,leveling valves ,shocks, brake chambers etc…. i have replaced a couple of regulators even the one above the lip in the middle of the back cap for the belt tension …

i know i have seen many posts about peoples aux compressor coming on in the middle of the night and waking people up … so i thought about putting one in some how on a switch . this way i get my beauty sleep on boy do i need it.

i did talk to the local shop and they suggested i go with one belt with three grooves … they said that belt is kind a pricey .

if any one has a xl close to my vintage do you all have AUX compressors ? if so where is it mounted ?

thanks Dave

[Archived]

I tried the single belt previously and didn’t like the vibration, so I stick with the 3 ordered from Prevost and suppose to be a matched fit.

[Archived]

My 1990 Marathon (which I bought used) was equipped with an aux compressor which I thought was standard Marathon issue and was equipped with a switch inside the coach. You definitely want a switch. My 2000 Liberty is also equipped with an aux compressor. Sorry, can’t remember where the comp was on my Marathon.

You can get fairly quiet compressors which will give you enough pressure (60psi) to handle your belts, doors, floors, etc. My current aux compressor will go to 115psi which allows me to re-level the coach if parked for an extended period but it is a bit noisy so it is only used for start-up (belts) and sparingly, hence the need for a switch.

[Roscoeapproved]

I would think if you needed to air up the bus prior to starting, Prevost would have build in a feature to do this, not leave it up to the converter.

---

Jeff and Lindsay

91 Marathon XL

[Archived]

If keeping belts tight before startup was important Prevost would be equipping the vast number of seated coaches with different belt tensioning devices.

My guess is when belts are thrown on startup one of the contributing factors must be converter added belt driven devices.

I have never owned a Prevost that had anything but belts driving Prevost factory installed devices such as alternators, AC compressors, fan, etc. and in 27 years I have also never thrown a belt.

[DON]

Jon,

Where is the valve that controls the Marathon Aux air Prevost Aux air? Is it in the driver door area?

[Kirby]

Steering bay Walt, yellow valve that combines Marathon aux with Prevost aux. Look in video’s of Interest and view my video.

[Walter]

My ’96 Marathon does not have one… based on the comments above, there seems to be no consistent factor (vintage, slides/no slides) that would indicate why some have factory installed compressors and others don’t.

Kirby

[Dick]

Thanks Tom, I saw it today. Is the idea to turn it off when parked for a while so that you don’t lose as much air due to leaks in the Prevost part of the system?

Dave, although our bus is a different vintage… our compressor is mounted on the top of the generator. And there is a pancake tank located in the drivers door compartment. I just replaced the pressure switch on it a few weeks ago.

[Archived]

The use of an aux compressor is dependent on different factors mostly related to how a coach is equipped and personal needs.

The first thing to understand is what devices are pneumatic, how the coach pneumatic devices are set up in the coach regarding mostly if they are from the coach accessory system or a dedicated converter accessory system, and why or if some devices or systems need air.

If a coach is being driven as long as all systems (chassis and converter) are being pressurized the aux compressor is not needed. If the coach is not being driven but is being stored out of the weather the aux compressor is not needed. If the coach is not being driven but is being stored outside, in the weather and has slides accessory air has to be provided to pneumatic slide seals which means usually an aux compressor must be powered up and pressurized air must be able to go to the Prevost accessory system.

I believe it is possible for Marathon accessory air to be trapped within the Marathon pneumatic accessory system if a valve is shut. In that case the slide seals (if they are pneumatic) are not going to be inflated and water entry is possible.

As we know each coach may be different not only between inverters, but also those from the same inverter. It is important to understand how a coach is equipped and set up (and maintained) because in some instances an oversight or failure to know how the systems operate can lead to very expensive damage.

[Archived]

Walt,

Yours being a slide coach may be a different setup than mine. Since you probably have Valid slides, I don’t know if your slide seals get air from the Prevost side or the Marathon side.

Mine is simple, the Marathon aux is isolated from the Prevost aux as long as the yellow valve is closed. I only have one aux compressor that feeds the Marathon side and if I want to add air to the Prevost side to air up the engine mini airbags, I open the valve.

I keep that valve closed because the aux compressor makes lots of water and I don’t want it contaminating the Prevost side.