Air Line Problem

[tdelorme]

Went to the bus barn yesterday to load up for a short trip to the racetrack this week. The aux. air compressor was running and I could hear a leak. In the steer bay, one of the 1/4" air lines was broken at a connection for no apparent reason. After shuting down the compressor, I cut off the old compression fitting and replaced it with a quick connect fitting and turned the compressor back on. Air pumps up just fine and I find no leaks at the repair. About ten minuets later, the line breaks again. When I fixed it again, the same thing happened. What I have found so far is that the line that runs back into the coach seems to have lost it's integrity. It will crack and break soon after any pressure is applied. The line that comes from the compressor is fine, it looks like new. The air line supplies air to the fresh water fill valve. Quick fix was to plug the supply line and holler for help. I am running out of line to fix as it has gotten shorter and shorter with each attempt but I have not found an area where the line is still good. Thats bad, I know, so has anyone ever run a new 1/4" air line back to the wet bay in an older Liberty? I think I can live with it for awhile, and when I get time I will call Liberty and get their 2 cents on a fix, but just looking for any help that might be out there. Thanks

[dalej]

Ted, We just plummed a 1/4 inch tube from the steer bay through the forth bay, for our bay doors air lifts. Jan and I wern't talking afterwards. :)

[Jon Wehrenberg]

Ted,

If I had to wrestle with that problem there are two routes I might take.

Since it is air I would go out the bottom of the steer bay and run the line the length of the coach through a groove I made just behind the angle that runs the length of the bays. It is just under the polished stainless door threshold trim and behind the bottom flange of the bay door. After you grooved it out for the new air line you could install the air line and re insulate it with that spray foam. The foam insulation serves as sound deadener so it is not critical but it would hold the airline in place instead of using some other type of adhesive. Once you got back to the bay you could decide wher and how to route the line to the valve.

The second choice, and not such an easy path would be to feed it through one of the tubes Prevost installs to carry wiring and air lines from the fron to the rear. There is access to the tubes by dropping the bumper and looking up at the top rear of the Cruise Air compartment. Those tubes run to the rear and at least one exits at the rear bulkhead of the water compartment ahead of the drive axle. I would probably apt to go that route and I would use a snake or line plumbers and electricians use to fish the air line through the plastic conduit.

Either way it will be work. I think I would rather eat bees than go through what you are going to go through. Especially since this repair doesn't do a damn thing to increase the value of the coach. But think of the quality time you will be spending with your coach.

[tdelorme]

Yep, about what I expected. Thanks Dale & Jon. So you don't think tapping into the holding tank line in the wet bay would work? I guess Liberty would have done that to begin with, never mind. To hell with it for now. I'm going to Texas Motor Speedway and watch Danica kick some butt at 220 MPH. Or not :)

[Kevin Erion]

Ted, if you want to join Erion Racing kick some butt, we are racing at Elkhart Lake, WI this weekend. I will help with the air line and we can eat some great brauts, best track food I have found at any race track in the last 20 years.

[dalej]

Ted,

One thing that I was wondering, can you pull the new line through using the old line as the fish tape?

[Jon Wehrenberg]

Ted,

Liberty pulls their auxiliary air from the Prevost port in the steer compartment. The lines are then manifolded and from the manifold go to the device such as air floor, dump valves, seat, air horns, etc.

They do this because that way if there is a failure of a line the protection valves come into play and this protects the integrity of the bus air system. I would strongly urge you not to pull air from any other location although it is far easier to pull air from tanks in the rear. You may even have an auxiliary air tank back there. If you can connect downstream from a protection valve you accomplish the same, but it must be on the aux air part of the system.

Not me. I'm a chicken.

[tdelorme]

Ted, if you want to join Erion Racing kick some butt, we are racing at Elkhart Lake, WI this weekend. I will help with the air line and we can eat some great brauts, best track food I have found at any race track in the last 20 years.

Would love to be up there with you guys, Kevin, but a little far for a weekend trip. Hope you do well and have good weather. We're at the track this morning and the wind is gusting up to 40 MPH. The bus is rocking like a boat so I think I'll go dump the bags and see if it settles down. GO FAST!!

[Joe Cannarozzi]

Ted if that holding tank line you were considering tapping into is aux. air that would be acceptable. Your talking about the line to the air dump valve for the waste water right? If so that is aux.

Dale had good advice too, I have done the same many times.

[Jon Wehrenberg]

Joe,

It would not be acceptable unless he tied in downstream from a protection valve. Failure of a line installed in the wrong place will not only bleed aux air, but it will pull brake system air until the air pressure falls to the 70 or so pound switch pressure.

If it installed downstream from a protection valve however the entire line can be ripped out and there will be a barely noticeable drop in brake system pressure.

[Joe Cannarozzi]

Wouldn't Liberty have taken that into consideration when plumbing air to the dump gate on his holding tank?

I guess it is better not to assume and check first by pulling the line he is thinking about tapping into and see what happens????

[Jon Wehrenberg]

Liberty plums a line from the Prevost aux air attachment port that is labeled "converter air" to a manifold. On my coach I have six lines from that manifold to devices such as the floor slide, air horns, dump valves, generator air bags, driver seat, pocket doors and bed lift. Since they come from the Prevost supplied port they are afforded the necessary protection.

It would be significantly simpler for Liberty to plum the air lines for their needs from the rear aux air tank because the bed lift, generator air bags, dump valves, and the pocket doors are all toward the rear of the coach. I suspect they have multiple reasons. The first I stated above, but they also can isolate leaks and problems by blocking them one at a time at the manifold to easily determine the air circuit that has problems.