Community Forums

Fefanatic · 02-25-2023, 04:45 PM

OK, so we had an issue with the air dryer on a '04 DSDP and hopefully we caught it in time. The issue was a air leak in the pop off valve on the Wabco air dryer and it was allowing the compressor to run every 30 seconds. That put a lot of water into the air lines. Some of that water is rusty and we would like to flush that rusty water out before it causes sticking valves and other issues. Water is orange and not thick so hopefully we can flush the system.

Any suggestions??

Ray,IN · 02-25-2023, 05:50 PM

I assume you've already rebuilt the air dryer and replaced the desiccant filter, if so you cannot get more water into your compressed air system. IF you have not, I suggest doing so immediately. Have you pulled the manual tank drain valves to drain out all water?
If you are still draining out water from both tanks (mine has 3 tanks) the air dryer is not functioning properly. There is no way to clean the inside of compressed air tanks other than daily draining and frequent use of the coach.

If you have allowed water to enter the braking system, its going to be expensive to repair.
Without knowing which chassis you have, this is all I can offer about draining the compressed air tanks.
That is for a Spartan chassis but should also work fine for other brands.

TandW · 02-25-2023, 05:51 PM

Good question! Well, we all know brake fluid attracts water, and of course brake fluid transmits pressure. But does it become explosive when high pressure air is present? Maybe someone else knows more about this. If it can be added into the receiver somewhere maybe it can draw that stray water to it, to be blown down later. Maybe you just need to disconnect lines one at a time and just give each one a good blow. I can tell you from past experience that an unloaded compressor that continues to run can build up enough oil to cause a catastrophic explosion. So your air system will always have a minute amount of compressor oil within the receiver and the lines. Maybe you and I both are too worried over this. Hey, good luck with whatever!

Fefanatic · 02-25-2023, 10:44 PM

We had to rebuild the brake and air system about 18 months ago. Problem was rust and water then. We replaced the complete dryer assembly then and it failed causing the compressor to cycle every 31 seconds. That generated a bunch of water again and we are trying to avoid rebuilding the system again. Last time we replaced the brake control valve up front, a couple of level sensors, we had water in the brake pods and cleaned them.

We have a new drier on order again and want to get the system cleaned before we do hae to replace a bunch of parts again. We are going to remove air lines and clean them out but was hoping that we could find some kind of fluid we could inject to clean the valves and other sytems.

Last time it got expensive and if we can avoid a repeat we want to.

It's on a Spartan chassis. And yes, we are draining the tanks and getting water.

Ray,IN · 02-26-2023, 04:27 PM

fefanatic, My Spartan MM chassis has automatic water drains with the manual drain in the side. Your chassis should also have automatic water drains that might be plugged with rust particles.
Old heavy duty trucks had a container on the compressed air system to facilitate adding antifreeze to mix with, and evaporate any water, and prevent water in the system from freezing. https://www.anythingtruck.com/product/070-A72420.html
Caution about the instructions in that link; If you need to put Air brake antifreeze in your compressed air system do it after the air drier , it will turn the desiccant pack to mush if you put it in before. only use straight alcohol in emergencies because it dries the seals out. Air brake antifreeze has lubricants added to prevent this.

Ray,IN · 02-26-2023, 05:34 PM

Addendum; I forgot to say, use the manual drains to completely empty the air storage tanks, then unplug and unscrew the 12V automatic drains to clean them out if you suspect they may be plugged with rust.
Be careful underneath the MH, several years ago an RV technician was pinned and smothered to death when he failed to exercise the required precautions before crawling under a MH with air springs.

Fefanatic · 02-28-2023, 05:11 PM

Thanks. I've given this a lot of thought and plan to use air conditioning flush compound. Taking lines loose and blowing the cleaner through them and then through the brake valves. We just want to flush as much rust out as possible before we put this back on the road. We've replaced the dryer. It was the source of the air leak causing the compressor to cycle every 31 seconds.

Fefanatic · 02-28-2023, 05:18 PM

Thanks. I've given this a lot of thought and plan to use air conditioning flush compound. Taking lines loose and blowing the cleaner through them and then through the brake valves. We just want to flush as much rust out as possible before we put this back on the road. We've replaced the dryer. It was the source of the air leak causing the compressor to cycle every 31 seconds.