2011 367 that wouldn’t build air this morning

Unloader valve(s) was likely stuck. Depending on the compressor there are unloader valve kits that can be installed with the compressor on the truck. You can also spray a penetrant/lubricant around the valve. A good idea to also rebuild or replace the air governor if it has been on there for some time.

 

Spray down the cloth discharge line with soap and water. Most leak where the steel pipe or meet the cloth hose. I would suspect a leak or blockage in the discharge plumbing from compressor to dryer.

 

Have you replaced the dryer cartridge? They sometimes get so full of moisture that they build slow.

Air compressors wear out and cause slow build complaints.

While checking for leaks, it's much easier to do if you can use air from a different source, like an air compressor inside a shop.

I would do a quick check removing the supply line from the dryer. Start the truck and just see how much air is moving. Then do the same on the outlet side of the dryer and see if there is any difference.

 

Definitely check for leaks, but also do what I said looking for a change in discharge volume. You shouldn't lose hardly any between the compressor and tanks.

That could help identify a blockage and it's location

 

Maybe when the secondary tank was delayed to fill you might have had water freeze in the pressure valve, as a little of the warm are rushed over the ice it slowly melted it. I actually see this quite often in the winter with on site repairs

 

Looks like yours was made in 2010 from the 1510, though the tags are slightly different.


These are Wabco unloaders. Does your truck have anything that looks like this? If not there is a reed valve in the head and head repair kits are sold. Given its age it makes more sense to replace the compressor/.
What about an air intake hose to the compressor? Make sure that is not kinked....
"My thoughts are whatever that air does inside the compressor to unload and load the compressor is not working as it should."
Correct and that is what I stated in post #2. I found out the same thing, can't find much on the Wabco's.