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Kyle,

Our vinage are a bit apart but my front 5 way valve is in the center of the bus above the front axle. You have to get the bus up a bit and block the chasis to gain access to the wheel well. Blocking is essential as you will let the air out of the bags when working on the system and it will come down.

The leak could be a bad valve, fitting between the valve and bags or one of the bags. Soapy water might find it but bag leaks at the bottom flange are hard to find.

Noticed the last line of your signature. Send me an e-mail some time.

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Kyle, I believe your coach has 2 3 port Norgren spool valves located up in the steer axle ceiling area, fed from 2 3 port Norgrens located in the steer compartment.

When the key is off the two three port Norgrens above the steer axles are blocking flow into or from the air bags. If I were to investigate the leakage allowing the front to drop I would start at the ride height valve which is common to both sides. Then I would look to the Norgren valves, their fittings and then the air bags. You need to get under the coach but do not ever do that unless you have supported it at the chassis support points and that includes access from a pit or lifts. Any time you are dealing with the suspension the potential for it to drop is greatly increased.

Soapy water will likely be the best tool in this instance. Don’t overlook the small “ping” tanks at each air bag.

The only leak you will not be able to detect will be one located on the bottom of the air bag where the rubber is bonded to the can, and the can is hidden behind the lobe over which the air bag rolls.

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If I understand Joe and Jon correctly there is nothing that can be investigated without going underneath – which rest assured,I will not do. All the valves you mention Jon are out of reach? Will shoot you an email Joe. Thanks.

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as in pressure vessels? Point being we have 2 traction steam engines running condition . 1905 Huber & 1925 Keck gonnerman. My son worked for B&W for a long time. Curious Bob

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Kyle, the reason the front settles down is because air is not “locked” in the aiur bag suspension. So that isolates the leakage to the air bags, air bag fittings, the valves that are pressurized when air is “locked” in and the associated fittings and hoses.

Unfortunately every suspension system on your bus (you have three, a front, LH rear and RH rear) is situated so you cannot do a complete job of leak checking unless you are under the bus. On an H and XLII coaches you can remove or flip up the fenders in the rear to get some limited access, but in the front it is much more difficult because you really do have to get under it.

In the good old days the suspensions such as on Joe’s coach were significantly less complex and they used compression fittings which almost never leaked. That is no longer true because later coaches have ping tanks in addition to air bags, more Norgren valves, and push in fittings instead of compression. So you have significantly more opportunities for leaks. Pull up the pneumatic diagram for your specific coach from the Prevost Publications Page. If you follow it you will see how all the components are in relation to one another so if you can borrow a service pit at the local truck stop for an hour you might find the leak.

You can safely slide under your coach if you block up the chassis. But for sure if you turn the coach over to someone for repairs you might want to consider bringing a small pile of benjamins because leak detection requires time and patience and there is absolutely no way to detect every leak without patiently and methodically checking everything possible using three or four different methods.

[Kyle]

Yes Bob. Have a lot of friends at B&W.

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Thanks Jon. Went from solid as a rock to a very slow bleed in front so I believe its a single leak. Was hoping I could get to it. Thanks for your direction.

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It could be as simple as a Norgren valve with a small leak, but whatever it is will take a careful, methodical and systematic approach to detecting the leak. You coach is aging and I can assure you of one thing. Leaks will begin popping up from time to time. The problem is all the probable leak sources have rubber for sealing, from the small internal O ring in the fittings and valves to the rubber in the air bags.

As the rubber ages it loses its ability to provide an air tight seal. If you were to count the valves, fittings and devices that are on our coaches that seal against air leaks you likely will wonder how it is possible to not have leaks. I know from experience it can take a long time to find just one leaky fitting, or one leaky valve or one leaky air bag so since my coach will be 10 years old next year I have begun the long process of not trying to find all the leaks, but of changing out everything that has the potential to leak. For me it is not worth the time required to find them and fix them one leak at a time. So by one year from now I will have all new air bags, Norgren valves, compression fittings in place of the push in fittings, etc. And after that is done and the coach is as leak free as I can make it the clock will start ticking and as those repairs age I can plan on doing it all over again.