leaking air beams

[robertglines1]

I had this problem with my 8...fixed them by welding leaking areas...now rebuilding a 98 prevost..observation they have a seperate air tank between the leveling valve and the bag ,one for each,about the size of a gal paint can..mounted to frame...possible solution with just plumbing involved?  tanks replace air beam and retain ride?   Bob

[bevans6]

The air beams on an MCI perform three basic functions, as far as I can see.  They mount the air bags and essentially act as the suspension load path into the bus chassis.  I've always been very suspicious of the idea of roughly plating and welding up air beams - the very fact that they have rusted means that you should be pretty careful about ensuring their integrity.  I've seen pictures of beams rotted all along the seam where they attach to the floor of the bus, with plated air bags, and I wonder if they are strong enough to support the bus for long...

The second thing they do is to interconnect the front and rear air bag on each corner, so the pair acts as a single larger spring.  Air pressure inside each bag is equalized with it's pair.  The third thing, and very related to the second, is they add significant volume to the air bags so that the ride is a lot softer than would otherwise be the case.

It sounds like your Prevost has air chambers that would act in a similar way as far as interconnecting and adding air volume is concerned.  How they actually perform would depend on how they are connected, any valves or regulators or such things, and the diameter of the hoses.

Brian

[mikelutestanski]

hello:    THe beam and bus design must be very tolerant because I have seen some bad rust cases still going.  MCI made a mistake when they added a piece of thin cheap angle to the top of the beam to fasten the fiberglass inner fender to and this angle usually disappears over time and leaves a pile of rust. Eventally the caulk fails and salt lays up there and works a hole through the beam. 
     
     THis is not a novice repair and requires welding skills above average in my estimation.
  FWIW    regards and happy bussin   mike

[robertglines1]

was just wanting to give option to block off plates..lines are the same size as ones from leveling valve that go thru tank to air bags..when I had the problem it was leaking problem that did"t effect structure of air beam..would have gladly used small air tanks rather than all the scaling and grinding to repair leak....valving is a open system after leveling valve. just a option..Bob

[JackConrad]

When MCI & early GMs used air beams, the used double convolute style air bags. When they did away with air beams, the started using rolling lobe air bags.  Which type of air bags are on your Prevost?  Jack

[gus]

I would guess that 99% of air beam leaks are via pinholes so structural integrity is probably not a problem.

My 4104 has one rear side plated and I can tell no difference in ride. It is a mystery to me why they were not plated originally?

The real advantage is quick bag inflation and reduced air requirement, those beams hold a lot of air.

[robertglines1]

Jack ,rolling lobe air bags 12r I think..maybe to enhance ride even more,was a entertainer coach.Bob