Replace an Air Regulator

[MangoMike]

The War on Leans continues. There is a number of air regulators on your bus, some are pretty well hidden and all are potential sources of leaks that need to be checked. Here's another Battle on this War.

598

HOW TO:

http://www.prevoman.com/Pages/Regulator/Regulatorpg1.html

mm

[truk4u]

Mango,

The regulator for your belt bellows should be above the rear engine access doors and I thought they were all in the same place since it's a Prevost supplied item. When I changed mine, I put a check valve in line to keep the air up even if the aux tank goes down.

Doesn't really matter, your valve was leaking and you fixed it, but just wondering what accessory the valve controlled.

[MangoMike]

Tom,

I need to trace it down as I really haven't got a clue. How about a part number / source for the check valve. Sounds like a great idea.

mm


http://www.prevoman.com/Pages/Regulator/comic.jpg

[Jon Wehrenberg]

Mike,

I opined on the other site it might be your bed lift regulator. I say that solely because if the two solenoid valves are part of the air circuit (they were not apparent from previous pictures, I suspect one is NC (for lift) and one is NO (to lower the bed).

You are just going to have to follow those air hoses.

While I respect Tom's opinion on things mechanical, the only advantage I see to a belt tensioner check valve is it will hold the belts tight as long as that portion of the system has no leaks. It will not address leaks in the aux system, so it is an artificial solution to the real problem which is aux system leak down.

[truk4u]

The concept oh great wise A-1 was to have tight belts on start up and not flip one off. I'm sure you have started the engine with the rear remote, while having collapsed bellows and watched the flailing belts. Pretty scary!:D

PS - Prevost in Nashville gave me that tip, they add the check valves all the time. I just wanted to do it myself.

Nana, nana, nah, nah

[Jon Wehrenberg]

In all seriousness I have not lost any belts upon start up even though the bellows have been completely flat.

Maybe it is a Marathon thing.

Nana, Nana, Nah, Nah.

But just to explain further now that I have pulled your chain.... For reasons unknown to me I leave my aux compressor on all the time. It doesn't cycle enough for me to worry about it and my air system still has air pressure even when I sit for a couple of months. But despite having air in all circuits my belt tensioners will be without pressure after the bus has been parked for a week. If you are confused, so am I because sometimes the reverse is true. The tensioners will stay pressurized forever.

That's the background. I am of the opinion, with nothing to back this up, that when I turn on the key, even if the bellows are unpressurized, turning the key on opens a solenoid valve or somehow allows pressurized air flow to them, and the pause between turning on the key and allowing DDEC to complete its check, is all it takes for them to get enough air so the belts do not jump off like they do on your coach, which may not have aux air pressure when you turn on the key.

[truk4u]

Jon,

I think your right about the bellows being pumped up when you turn the key, because you probably always have air in the aux via your aux compressor. Us poor non-aux compressor guys have to do things the hard way.:D I've never had a belt jump off, but the tech at Prevost says it happens.

I forgot, Kevin made a small bolt like devise that keeps the belts tight by not allowing the adjuster arm to collapse when no air is present. Better than my check valve because if he gets a bellows leak it doesn't matter.

Kevin - Send a pic

Mango - I put the check valve in line before air gets to the valve, but since you have a Liberty with an aux compressor, maybe non of my jumping through hoops matters.;)