1990 Pierce Arrow Type I Engine

[MichaelXYZ]

I hope this is not a dumb question. We just picked up 3 1990 type I engines without manuals. So far I have scrounged and finagled a fair portion of the manuals I needed with the exception of the apparatus itself.
Well here's the thing, I been doing my best to locate and familiarize myself with as much of the apparatus as I can. Well, while using my creeper and going underneath the apparatus, I been looking at the bushings, brakes, and other...

I spotted something with Class III leaks which concerned me, and I am embarrassed to say, I am not sure what the component is. It looks like a tank with some connections at the bottom (I am thinking Wet tank).
The black hose just hangs and looks like a drain hose, not connected on one end.
Attached is a photo I took, not the best photo but hard to do while scrunched up under an engine. Do any of you recognize this part. I have called pierce but have not yet found the right guy to speak with.



P.S. It was near the passenger side front tire.

Thanks

[rm1524]

It appears to be the air dryer. The oil would more than likely be the air compressor leaking.

[MichaelXYZ]

That's it, you da man. Thanks

[chiefengineer11]

If the oil is coming from the air dryer then as rm says, there's a problem with the compressor that needs to be addressed. An exchange compressor would be a viable solution. Also the air dryer will need attention as the dessicant pack in it is probably contaminated. I have rebuilt several of them in the past, but that was before exchange dryer units were available. Since in order to rebuild one you pretty much need to remove it from the vehicle, and since exchange units aren't that much more money than the parts to rebuild your own, it makes sense to me to go the exchange route. The last time I did that they gave me an AD9 to replace an AD4. Much better unit. Just my two cents.

[MichaelXYZ]

So what do you think could be going on with the compressor? Did it overpressure the dryer?

Thanks

[chiefengineer11]

So what do you think could be going on with the compressor? Did it overpressure the dryer?

Thanks

Looking at it from nearly 3000 miles away, my guess is that the compressor has worn parts such as worn out or cracked rings and is consuming oil. That oil passes into the air dryer and has contaminated the dryer's dessicant pack. It is now being expelled each time the compressor has the air system fully charged and "blows off," which is done through the dryer.

In addition to truck dealers there are many independent truck parts houses who sell these parts. Most of them see cases like yours on a daily basis and can give you good advice as well as providing you the parts (that's assuming you want to do the work yourself). If you do, prepare to get dirty and come out with skinned knuckles.

If you'd rather not, any competent truck dealer or independent truck repair shop can accurately diagnose the problem and do the work for you. The systems and parts involved are common to all trucks with air brakes, not just fire apparatus, so it doesn't require a fire apparatus specialist to handle it.

[MichaelXYZ]

That makes perfect sense, thanks.

[chiefengineer11]

One other thing - if that scenario is in fact what's happening, not all of the oil will be getting ejected via the air dryer. Some of it is probably being continued into the rest of the air system, and from there into parts operated by air - brake pots for example. So I'd offer the following suggestions: 1) Open each tank's drain valve every few days long enough to drain off any oil that may be present. 2) Check, or have the system checked and repaired without delay.