2019 KW T800 Had a lot of water in air tanks a few months ago, we changed out the air dryer assembly with an Automann and it's worked well. The other day the truck is having the same issue. We put another Automann assembly in it thinking the first was a dud. After 2 days of no problems, its collecting a lot of water again. Before I put a Bendix assembly in it, is there anything else we should check?
Does it work correctly? You know, several second purge at compressor cut out?
What has the humidity level been where your at. An air dryer can only remove so much, air tanks should be drained daily even with air dryer. * I doubt two bad air dryers.
it’s purging and cutting out like normal. Definitely high humidity here, but this is my only truck out of a whole fleet that’s having the issue.
What engine and where is the air intake for compressor located? And how much idle time?
X15. Compressor intake is at the turbo. Its a dump truck, so it idles more than I would like, but this driver is good at kicking up the idle when sitting.
It never shuts off. Time it between purges.
I believe time in between purges was something around 90 seconds to 2 minutes. We ended up putting a Fleetrite brand dryer in it and it’s got the same issue. I can only think there has to be another issue somewhere else.
Time between purge--is too fast, other issues like air leaks or bad governor can cause it to cut in too quickly. Normal air dryer purge time in a good system is roughly 20 to 30 minutes without system requiring too much operational air. Such as brakes, engine fan, suspension.
I’ve never put a stop watch on it, but whenever I check other good trucks in my fleet, they purge every few minutes.
Have one truck that makes a fair bit of water when using air for other things. Air dryer does its thing and added an auto-bleeder to the bottom of the air tank, each time you use air it dumps a few cc's Really helps and isn't expensive.
Every few minutes is too much. I just had to replace an air bag today, yesterday it was purging about every two minutes and was driving me crazy. New bag, it's up to ten minutes between cycles. The truck is a 21 year old IH, I need to rebuild all the pushlock fittings.
Started having issues on our dump truck this week. It doesn't run much, but we use it more right now then the rest of the year. Went to move the dozer for a brush cleanup job and it struggled to build 90psi. After a bit of troubleshooting, I figured out it was an issue with the air dryer and a rust hole in the wet tank. With governor signal line removed, air compressor would build 120psi air easily, even with the leaky air tank. I got lucky. Truck Services in Hamilton had the exact same tank my truck had, sitting on their rack in the yard. I had to change out fittings to how our truck is configured, but I was glad I was able to get an exact match tank. NAPA had me an air dryer that afternoon and truck was running properly by end of day. Had to drop fuel tank to remove air tank which is tucked under the cab. Spent more time chasing parts than turning wrenches.
Will say when it comes time for compressors, including all parts and time, may as well turn in a core on a reman. The last SS series Holsets I rebuilt the parts availability was getting tight and because of that the prices were steady on increase from month to month for same parts.
I'm pretty stoked about the dump truck now. It has 110psi on the gauge two days after I last ran the truck. It's never held air like that in the 10 years we've owned it. Actually, both of our L8000 Fords hold air really well now. Our other truck will still be over 60psi, 3 weeks after we used it last.
I'm still having this issue of intermittent water in the tanks. Is adding an automatic drain valve the way to go?
Several members have mentioned that the cycle time between purges is too short. You likely have a brake chamber, air line, air bag/leveling valve, or something else in the air system that is leaking air. The leak is making the air compressor run all the time ( which is causing the short time between purges). A auto drain is just going to mask the problem, your compressor is running too often, making water all the time. Find the leak, and you'll fix the water problem. One other thing to check is the unloading reeds in the compressor, make sure that they are kicking out, as well as the governor. The more the compressor runs, the more water it makes.
Check the engine fan clutch, it's one item that is often missed for constant air loss.
I’ll check these. Last time we looked at it we could hear the compressor unloading after purging and we checked other good trucks in our fleet and they had similar purge timing.
Sounds like its time to hook the supply tank to shop air and isolate the compressor for leaks, then work your way around the system, you might just have a lot of small leaks, Ideally a truck sitting off should hold air. Work with an 80's international it'll sometimes hold half a tank for a week. Tank is under the step, no air dryer but has an air tank auto drain along with the manual cable, I'll give the cable a tug once early in the day and then late, just a little mist will come out.
There is also the factor of dew point, which depending local can be added. Around here it's a dry climate and much rarer for air tank condensation no matter the shape of system.
I'm terrible about forgetting to drain tanks. Then we'll have a little cold snap and I'll have frozen up air lines. I was a lot better about draining tanks when I lived further north
If the air from the governor that unloads the compressor is leaking off that will also cause the compressor to cycle more frequently.
Correct--especially in a Holset 296 style compressor, amount of carbon/oil build up in those unloaders can lead to poor compressor operation, Bendix is a little better. On anything with braded hoses to governor, soak with soapy water, if old 9 times out of 10 will start to foam.