Background - In the fall, I replaced my Haldex air dryer with a new complete reman'd unit, not just the filter. I did have some white powder in the lines, which I have read there is not much you can do.
A couple of weeks ago during the Texas ice storm, I had to move the coach about 50 feet to avoid any potential tree limbs falling. When I stopped, I could hear a huge air leak from both sides under the front, but had other more important issues like heat and power to get going. After things came back to normal, I blocked up the coach to see where the leak was coming from. Huge bubbles were coming from the front air tank chamber's drain valve, specifically from the round relief opposite of the knob that you turn. I also could see burst of white powder coming out when I turned the knob.
I ordered one from Napa as well as a spare but did not get to replacement until today. Install went fine, but I am curious as to what the most likely cause of the valve failure is. It's been on a trip since the air dryer was changed. That said, what is the most likely cause of the valve?
1- just chance
2- related to the cold weather/ice storm?
3- related to the white powder in the line?
Hopefully someone more versed and/or who has run into this before can weigh in. TIA.
White powder means a previous filter failed. The desiccant can cause many problems such as keeping valves from closing like you are describing.
My guess 1 and /or 2
1= Murphy law
2=Started end of last year, when I have coach out in the deep cold. I started getting air leaks.
All 4 valves that are to shut off air to the HWH slide air bladder controls were leaking and had to have replaced after being in a deep cold area.
I don't think it would have been 3 unless you have been operating the valve, thus getting the snow hung up in the valve.
I've had three fail, it's hard to find a good one. I'd be willing to bet on the cold
Drain valve is there to drain moisture. I would guess it had moisture above on/it and it froze?
https://www.supplyhouse.com/Bluefin-BVT025MF-NP-1-4-FIP-x-MIP-Full-Port-Forged-Brass-Mini-Ball-Valve
You never should have continued on with dessicant powder loose in the system. You can remove and replace, or you can remove and clean air lines until you find no more contamination, but allowing that "white powder" to move through your braking system shouldn't be an option. Brakes should be classified as a life safety device.
To answer the question,cheap quality valves,my opinion,if anyone lives near a oilfield supply store research valves and get one from them,will be pricey but will last longer then us.Best one would be a needle valve.