air bag air compressor

[dbyar]

Hello fellow motocoach owners. Thank you in advance for good adivice. I follow the forum religiously.

All of the manuals that I have say there is a valve to tap the air compressor condensation. The coach manual says it is located on the curb side rear, however I can not locate it anywhere. The air compressor itself is located mid-coach behind the stairs, but there are no taps into it. There is condensation leaking from the hoses when the air compressor goes on to pump up the air bags. Anyone out there have a similarly equipped classic 350 le?

dbyar
Classic 350 le
Excella 1000

[87MH]

dbyar:

Regardless of the location of the compressor, you should have a volume tank located either just ahead of, or just behind, the tag axel. This volume tank should be about 10" in diameter by 2' long.

In the middle of this tank, on the very bottom, looking down, should be a valve that looks just like a valve stem. This is the "condensate drain". If you push the valve stem open, and nothing comes out, the valve may be plugged internally. To remove the pressure you could VERY CAREFULLY and verrrrry sloooowllly back off one of the hose connections to fully relieve the tank of air pressure, and then change out the "Schrader Valve" (the valve stem looking valve) on the bottom of the tank.

"Condensate" or air leaking from any hose or hose assembly indicates an abnormality. All leaks should be repaired. You can check for leaks with a water/soap solution. Mist the solution on all fittings, any leak should create bubbles.

If you do not feel comfortable working with the air system, please hire a qualified technician to trouble shoot the unit. Compressed air, even in the relatively low pressures of the coach air system, could create a dangerous situation.

[dbyar]

Dennis,

Finally found the "tap". Screwed out the schrader valve. There was no pressure A few drops came out. I am hopig that it was dry from disuse, rather than blocked further up in the tank.

I now have a related question. I am told that the air compressor itself needs to be maintained by having its oil changed. Do you concurr? This means grinding the welds off of the box that protects it where it is located under the stairs.

Thank you.

dbyar
92MH

[87MH]

I would recommend you locate the information tag on the compressor and write the manufacturer for a maintenance schedule, if your PO did not provide the original documents.

I have a Thomas on mine, but it is an "oiless" type, not requiring any maintenance other than replenishing the oil reservoirs on the motor bearings.

FWIW, the compressor in the '87 is NOT original, so it has been replaced at least once.

Good luck!

[ALANSD]

Do the bags stay filled? If so it may be the check valve will prevent air from remaining in the tank, and thus no air bleeds when the valve is open. My older ones work that way, no air can be released from the tank althought the bags stay pretty full. If I bleed air past the tank near the split where the two lines go to the bags, then the bags will collapse.

[kerwooddr]

Originally Posted by 87MH

I would recommend you locate the information tag on the compressor and write the manufacturer for a maintenance schedule, if your PO did not provide the original documents.

I have a Thomas on mine, but it is an "oiless" type, not requiring any maintenance other than replenishing the oil reservoirs on the motor bearings.

FWIW, the compressor in the '87 is NOT original, so it has been replaced at least once.

I have a Classic 345 like Dennis, and just recently found the air compressor under the starboard mattress. Can the outboard air fitting in the starboard aft exterior storage compartment be used to supply air, such as for filling the tires? There was some pressure when a put a hose into the fitting, but not much.

While the dash gauge says I have plenty of pressure in the suspension, I don't recall if I've ever heard the compressor come on. It didn't make a peep when I bled the pressure from the air fitting mentioned above. That was with the ignition key in the [ON] position.

Thanks.

Underway Battalion Operations And Training Support Vehicle
(U-Boat)

[87MH]

There have been many threads here where the workings (and non-workings) of the air compressor and air suspension have been discussed -- some with pictures.

To answer your question - absolutely the air system can be utilized for any air requirement via the access quick connect in the storage bay. There is enough volume in the tank to top off all of the tires and front airbags.

If you trace out the line, you will find the quick conntct is Teed off of the line FROM the tank TO pressure sensor next to the compressor that the electrical start sensor is connected to. The compressor discharges to another line that enters into the top of the air volume tank, with a check valve installed at the entrance to the tank. The line between the compressor and the check valve is bled off via another solenoid that opens whenever the compressor is not operating. The check valve on the top of the tank prevents the air from escaping while the compressor diischarge line is open to the atmoshere. This set up is provided to allow the compressor to start against a "0" psi head, and not having to rely on the discharge valve of the compressor to hold 100% against tank bleedoff.

Any pressure you read at the accessory quick connect will be the pressure in the tank. There is also a Schrader valve (looks like a tire stem valve) at the bottom of the volume tank. This valve should bve opened periodicaly to drain any condensate water from the volume tank. Either of these valves can bu used to add or remove air from the tank.

Do you know where the dash air pressure line gets its source? My 345 does not have a dash mounted air pressure guage.

Do a search on "Air Bag Height" †o get an idea if your rear airbags are properly inflated.

On the noise thrown off by the compressor, AS did a pretty good job of eliminating compressor noise from the cabin. I have to have the compressor access hatch open, and be in the bedroom before I can hear it running.

There should be 80 to 100 psi in the tank during "normal" operation, but the airbags may operate properly with significantly less, depending on the load.

[swebster]

David,
Welcome! In fact, my 345 has been plumed with a standard air quick disonnect in the passenger side rear baggage compartment and came with a coil hose and air chuck for filling tires. It's also usefule if you need to clean things with short blasts of air. It certainly couldn't run an air grinder for very long, but it works great for me when filling tires away from a truck stop.

[kerwooddr]

Originally Posted by 87MH

To answer your question - absolutely the air system can be utilized for any air requirement via the access quick connect in the storage bay. There is enough volume in the tank to top off all of the tires and front airbags.

That's what I thought, but I had no pressure at the external connector, which threw me off a bit. That tells me that there is either a check valve or some other mechanism between the tank and the external connector which is blocking air flow to the connector.

The gauge on the dash was an option I believe, in lieu of (or possibly in addition to) the warning light. The bags look to be in good shape, good and taut.

[kerwooddr]

Originally Posted by swebster@myrvadvanta

David,
Welcome! In fact, my 345 has been plumed with a standard air quick disonnect in the passenger side rear baggage compartment and came with a coil hose and air chuck for filling tires. It's also usefule if you need to clean things with short blasts of air. It certainly couldn't run an air grinder for very long, but it works great for me when filling tires away from a truck stop.

That's exactly what I was hoping for - a source for utiity air.

My Cadets would love the "Land Shark" paint scheme on your vehicle.

[swebster]

Actually, that P40 nose is only a concept right now. I did that a long time ago using Adobe Photoshop just to see what it would look like. Actually, I like it so much I plan to have a local vinyl graphics place make them for me once the nose is polished.

Check your baggage compartment for this connection already. It may already be in place.

[kerwooddr]

Originally Posted by swebster@myrvadvanta

Check your baggage compartment for this connection already. It may already be in place.

Right, and it is in place. Just no pressure.

[Jim Tyrney]

David,
If you have any info on the dash mounted air guage such as wiring diagram, I would like to get a copy if possible. My 86' 345 has this guage mounted on the lower dash but it is not working. Have you run across the sending unit for this guage? Mine seems to be electrical rather than pneumatic. If anyone has any info on this dash mounted guage, I would appreciate hearing from you. Thanks, Jim