Air Release

[epretot]

Is there a way to release all of the air from the bus after shutdown?

The bus is leaning a bit. And while that needs to be investigated, this would be helpful to remedy the lean when working on the bus.

[tr206]

You can put a dump valve on your air ride suspension is that what your asking?

[luvrbus]

You can dump the air at the rear where aux air connection is located and there should be another one up front under the drivers window

[epretot]

You can dump the air at the rear where aux air connection is located and there should be another one up front under the drivers window

Great...I'll give that a shot.

I'll have to find the rear one.

[Coach_and_Crown_Guy]

There isn't usually anything between the leveling valves and the air bags themselves. A single line with the leveling valves as the only thing controlling the air pressure going to the bags. The gradual leaning and or eventual drop of the air suspension is directly related to how tight the air connections are from the leveling valves and the bags. The leveling valves may be leaking ever so slowly as well but not likely or noticeable when air is available to make up any slight loss. All you can do is to get in the line to the airbags and add a drain yourself. Remember that any extra fittings, joints, or drain valves you add increases the likelihood for further leaks and more points of failure. KISS is a good rule of thumb to keep in mind.

There are check valves to keep air in the suspension system. Draining the air tanks in the bus won't affect the suspension system as long as the check valves are still functioning. The leveling valves act as the single point for adding or releasing air pressure to the bags in order to maintain the set ride height. They also act as a check valve too so if the bus air system is completely drained the suspension system will stay up until the air eventually bleeds out very slowly, unless of course there's a slight leak that will cause it to settle a little faster than designed.   

It's common to have three leveling valves, one at each end of the rear drive axle, (left and right), and a single one up front for the front axle. That's three separate drains if that's what you really want to do. Otherwise it's probably best to leave things alone and accept the very old fact that they will lean and settle as the air bleeds out of the air suspension system. A lean means one of the lines is bleeding faster than the others, try looking for that leak, and good luck because it won't be easy since it's probably a SLOW leak. The leaks could be anything from the airbag itself, they can wear and crack, to it's mounting point, to the fittings along the way to the controlling leveling valve.

[epretot]

There isn't usually anything between the leveling valves and the air bags themselves. A single line with the leveling valves as the only thing controlling the air pressure going to the bags. The gradual leaning and or eventual drop of the air suspension is directly related to how tight the air connections are from the leveling valves and the bags. The leveling valves may be leaking ever so slowly as well but not likely or noticeable when air is available to make up any slight loss. All you can do is to get in the line to the airbags and add a drain yourself. Remember that any extra fittings, joints, or drain valves you add increases the likelihood for further leaks and more points of failure. KISS is a good rule of thumb to keep in mind.

Thank you. I'll consider just leaving things alone. It's just seems to have gotten worse suddenly.

I'm adding air into the reserve tank under the driver seat to air the bus up with a compressor. Is that OK?

Wondering if that could be a factor. However, I've been doing that for the duration of the conversion.

We moved into the bus and I have been forced to leave the bus aired up so it doesn't lean.

[chessie4905]

I had that problem on a 4905 shell. I have a pit, so much easier to check. Rear bags on one side would leak down, so disconnected the tee going to the two bags on that side. Rigged up a schrader valve to connect to one of r0the bags and inflated to 90psi. Checked next morning. It was still up. So, hooked to second bag, and overnight it was flat. Replaced bag and allis well. If both were ok, would have to to be levelling valve.
A schrader valve is like the tirestem valve. They make one with 1/8" or 1/4" pipe threads on the one end. Just need the right adapter fitting to connect to air bag. On older coaches, can do similiar test to isolate and check for leaking air beam.
If everything is leak free, system should stay up for months, unless a lot of movement inside of coach triggering levelling valves.

[epretot]

If everything is leak free, system should stay up for months, unless a lot of movement inside of coach triggering levelling valves.

We are staying in the bus to test everything out. So, there is a lot more traffic.

I'm going to post a pic later today of one of the airbags. It doesn't look quite right to me. But because of my inexperience with buses, it could be nothing at all.