Where to buy parts (wet tank) and is my troubleshooting (air level) good?

[philiptompkjns]

ZZ,

Same thing happened to my wet tank, completely bypassed and I didn't know it for a long time!!

I found a wet tank on ebay. Take measurements and the dimensions and locations of the holes and look for one that will work. Many air tanks have multiple holes for different applications. The prices from MCI or a bus supplier will make you sit up and take notice.

On the leveling valve problem; I just went through this last week. One side would take a very long time to rise properly. Turned out to be a clogged external check valve. Cleaned it out added some air tool oil and all is well.

The valve was not an original which has an internal check valve. Some original valves also have internal air filters which can clog. My external air filter was missing the pyramid shaped filter screen so I made another one.

hey ZZ and gus.... besides reduced air reserve, does not haveing a wet tank adversely affect the air dryer?  Also, is there anything wrong with useing a normal air tank (one hole only) with a T, as a wet tank?

[bevans6]

There is always a wet tank, since the definition of a wet tank is the first tank in line from the compressor.  If you bypass the wet tank and go directly to the dry tank, then you no longer have a dry tank.  You send all the moisture that should be captured in the wet tank to all the rest of the system.  No, a Tee on the outside of the wet tank will not work.  The air needs to expand into the wet tank, that expansion causes a cooling of the air, the cooling of the air is what causes the residual moisture to condense out, and the cooled and dried air then goes off to the dry tank out a different port.

brian

[zubzub]

my old bus only has a wet tank as an air dryer, but my understanding of air dryers is that they come before the wet tank so I don't think their absence would change the way a dryer performers.  But remember I am not a professional bus mechanic, just a bus nut with too much time on his hands as I wait for some contracts to come rolling in the door.......still waiting.....

[philiptompkjns]

my old bus only has a wet tank as an air dryer, but my understanding of air dryers is that they come before the wet tank so I don't think their absence would change the way a dryer performers.  But remember I am not a professional bus mechanic, just a bus nut with too much time on his hands as I wait for some contracts to come rolling in the door.......still waiting.....

well, you are probably correct because lots of water was dripping from my air dryer when it purged, but the wet tank was completely empty.

[bryanhes]

I had been chasing some air leaks in mine as well  Although not bad. Maybe 10-12 PSI in 15 minutes with the engine off. I did find the culprit for what I believe to be a major contributor. My wet tank drains. I sprayed them down yesterday at the two air release valves and had bubbles a blowin. I would say that when I replace them it should hold pretty well, I hope 


Bryan

[gus]

As Brian says, the T won't work. There also needs to be a hole for a drain and a hole for the pressure relief valve. My governor failed once and the pressure was building to 150 psi so the relief valve saved the rest of the system. On my bus that is the only relief valve in the system.

4104s don't have air dryers.

I had a drain on the dry tank and did get a lot of water, that's the reason for the drain.

Now that the wet tank has been replaced it gets very little, but some.

The bypass was impossible to see, I actually found it by feeling.

The really weird part was that I could never tell the difference in brake or suspension operation and still can't. I drove the bus two years including over the Rockies and a bunch of other western mountains before I discovered this.

After this experience I can't imagine a real problem with one tank unless a big air leak happened suddenly and you needed some time to get it parked out of traffic.

The only difference I can tell now is it takes much longer to air up after a long sit.

[buswarrior]

gus, the opposite of longer to air up after you sit....

under an air failure, your air would be GONE really quickly... when your wet tank was bypassed.

the greater the volume of available air, the more you can use the brakes, or the longer you can withstand a leak, before there is trouble stopping.

The previous owner should be shot for selling you the coach in that condition without telling you.

happy coaching!
buswarrior

[philiptompkjns]

You may want to consider putting soap and water on the suspected tank to see if your assumption is correct before spending the money since, as you said, it may be leaking somewhere else. 

yup, it was the wet tank:

I can't believe it even aired up enough to drive it like this.

[robertglines1]

if new one is out of reach ck truck wrecking yards ...air brake storage tanks         on trailers (semi) make sure to ck under straps for rust (like yours) leveling valves are less than 50 bucks ea  air bags usually leak at top       where metal plate bolts to frame  there is ck procedure for leveling valves if you need help ;post

[philiptompkjns]

if new one is out of reach ck truck wrecking yards ...air brake storage tanks         on trailers (semi) make sure to ck under straps for rust (like yours) leveling valves are less than 50 bucks ea  air bags usually leak at top       where metal plate bolts to frame  there is ck procedure for leveling valves if you need help ;post

sure, do you have to procedure for testing the leveling valves?  I disconnected the arms and the line going to the bag and manually messed with them a bit and no air came our of the line no matter what I did.

[Jriddle]

Philip

I removed my leveling valves and installed a Manuel system from Pete. If you or anyone else wants my old valves send me a PM and we can arrange shipping.

John

[robertglines1]

remove ....put air supply to inlet ....put in bucket of water....in neutral position....no air passing....then operate and hold for 10 seconds should put air out appropriate hole.....if doesn't work toss across shop.... one air bubble every 5 seconds or so is acceptable.....test air bag when line is disconnected.make up fitting to put air in bag W/gauge and ck valve or shut off valve               and see if it bleeds off.keep set up you can use for many test in future...soapy water is a busnuts best friend when chasing leaks...dish detergent works well  ...Air bag should not loose any pressure at all.some air bags are t-ed to another will have to isolate...once you get into process you will be able to rule out system problems by areas. example you can ck the t-ed air bags then if you have drop ,isolate to determine which one...good luck ....Bob