It's time for me to replace a Bendix DV-2 Automatic Drain Valve for the wet tank. Any recommendations as to whether I should stick with Bendix or try other brands like Haldex, PTP, etc. I also saw mention of an Electronic Drain Valve by Expello, but would it be dependable?
I have the Expello on the Country Coach they are dated 2007 not a problem yet they still work when you push the button,I had the Bendix automatic on the Eagle they are easy to rebuild most of the time all that was needed was a new 25 cent valve like you find inside the valve stem on a tire and you don't need to remove the whole unit to replace it
The Expello is used on Peterbuilt's and Kenworth's, but the best price I have found so far is $169.95. Maybe I should try repairing the Bendix since I am so cheap. :o
Never been a fan of auto drains. Horrible reliability.
A busnut WANTS to know what is coming out of there, and witness its passing, the volume, the consistancy and the content. A bit of water, a lot of water, brown goo, black goo, a stream of oil...
And when does the busnut discover that the "automatic" isn't anymore?
Invented to sell to fleet owners, trying to do something about drivers who wouldn't drain tanks... that typically isn't the busnut crowd, we have a vested interest in the proper care and feeding of the coach...
Just my 2 cents, if you like 'em, replace 'em.
Happy coaching!
Buswarrior
You can buy the aftermarket with a heater for 35 bucks.you really need the heater because they don't work in cold and freezing weather On Eagles those were standard OEM since the 05,they make a pneumatic auto drain that cycles with the compressor but I forgot who makes those my dump trailers used that type and we never had problems with those
Quote from: buswarrior on September 24, 2020, 07:29:08 PM
Never been a fan of auto drains. Horrible reliability.
A busnut WANTS to know what is coming out of there, and witness its passing, the volume, the consistancy and the content. A bit of water, a lot of water, brown goo, black goo, a stream of oil...
Buswarrior
Not quite horrible, but they certainly can malfunction. The manual valves with the pull cable can act up as well, and not seal up okay because of the crap coming out. Another plus for automatics is that some old guy has one less thing to stoop down for. ;)
I like the manual as well, but I really wonder how many people actually drain them at the end of every day? If they are not emptied daily, they're definitely less useful than the auto systems. Either system, drained regularly, should not have anything in it but water unless there is a problem.
If we drove regularly in freezing weather I'd consider adding an auto system with a drier, but since we don't I'll stick with the manual for now.
A good dryer set up makes drain valves almost obsolete...
Put the manual drains with pull cables on my bus and i always drained them every time i ran the bus, even if it was only for a few minutes.
Quote from: dtcerrato on September 25, 2020, 07:16:40 AM
A good dryer set up makes drain valves almost obsolete...
Yes and no.
When they work properly, they will remove the moisture. But, it's still a part of a post-trip inspection on commercial vehicles to pull the cables and confirm that there is no water in the tanks.
No way to know if the drier is working if the tanks are not blown daily.
So, now that I have the bus up on stands, how hard should you have to pull those to open them? I don't have any cables so I guess I should add them on. Is there a preferred way to do that?
Jim
Another thing... the drains really aren't at the bottom of the tanks, so how much good are they really if they leave 2" of water below them?
one of mine with the cable on the 4104 developed a pin hole, causing a small leak. I would have never fount it without my pit. Mine have cables that run to outer edge of wheel well. You may need a loop of some kind in the middle area so the lanyard doesnt rub over parts.Out of sight and away from tire swing on front. Also have Bendix ad 9 air drier on both
Unless it has changed since I stopped doing DOT inspections tank drains and air dryers were not required as part of a DOT inspection. They are getting nasty about a certified tech working on brakes on commercial vehicles they just pulled a friends of mine DOT inspections for no certified person, no more inspections for him, Canada has that rule for years
I replaced all my pull drains in the spring and installed new ones and put a small loop cable ( 5 " long ) so I can pull them with the awning thingy ( 4 ' long ) that I use to get at all the window awnings
works for me
dave
Quote from: luvrbus on September 25, 2020, 10:49:50 AM
Unless it has changed since I stopped doing DOT inspections tank drains and air dryers were not required as part of a DOT inspection. They are getting nasty about a certified tech working on brakes on commercial vehicles they just pulled a friends of mine DOT inspections for no certified person, no more inspections for him, Canada has that rule for years
Don't know about the DOT checking them during their inspections, but without a doubt they were a required item on our post-trip inspections. But, I seriously doubt that many drivers actually did complete post-trip inspections judging by what I saw.
Quote from: Jim Blackwood on September 25, 2020, 08:06:48 AM
So, now that I have the bus up on stands, how hard should you have to pull those to open them? I don't have any cables so I guess I should add them on. Is there a preferred way to do that?
Jim
Another thing... the drains really aren't at the bottom of the tanks, so how much good are they really if they leave 2" of water below them?
Lol I had the same thought.
My valves have rings on them, but they open by pushing not pulling. It is just pushing against some spring pressure so not very hard. Pushing or pulling to the side seems to work.
My statement about a good dryer was made because since it was installed no moisture has exited any of my pull cable tank drains. Made a believer out of me. I still pull the manual drains but not as often...
Having an air drier should be an essential item anymore on our coaches especially older ones to extend the life of the air brake components. Rusted through tanks are showing up more as our fleet ages. Daily draining helps, but that moisture is still there. Dry air systems are invaluable to avoid freeze ups we read about every winter season here. Nobody wants to spring $300+ dollars on something they feel isn't essential, but should seriously consider.
Btw, if you drain your tanks and see oil, sludge combination coming out, leave tank drains open over night or a couple of days to completely empty the tanks of that crap. Like draining an oil jug overnight. Noticeable amount of oil still comes out.
At the very least, install drains with lanyards. They aren't that expensive, and once installed, avoid having to get under coach. Biggest decision will be to determine the length of lanyard.
Re: mci drains up the side of the tank
Up there to avoid road debris snapping them off and disabling the coach.
It is not the outlet location that matters, but the intake location... anyone cut one open?
I was told similar to propane tanks, it has a pipe inside to the bottom.
Happy coaching!
Buswarrior
Seems like the wet tank on my 4108 drains the same way - the petcock is actually next door by the fuel filler, and the tube that feeds it from the tank has to go uphill a bit. My thought is that it relies on the air pressure to drain the water, so leaving it open overnight isn't going to help.
Richard, read your GM service manual. Leaving open overnight better allows oil and slime coating tank to slowly drain. Also, when draining tanks, more water will be expelled at middle to lower pressure than at full psi.
Richard, is this "uphill" something added on external to the tank?
Happy coaching!
Buswarrior
Quote from: chessie4905 on September 26, 2020, 08:15:45 AM
Richard, read your GM service manual. Leaving open overnight better allows oil and slime coating tank to slowly drain. Also, when draining tanks, more water will be expelled at middle to lower pressure than at full psi.
I hear what you're saying. However, the drain lines from the wet tank go uphill to get to the petcock inside the fuel door. Leaving the petcock open overnight isn't going to drain anything that drips overnight - it's just going to collect in the lower portion of the drain tube.
With the liquid collected in the lower portion of the drain tube. It's not going to be expelled until there is enough pressure in the tanks to push it out. Perhaps what I need to do is start blowing the tanks during the pre-trip as well after pressure builds to blow out whatever has collected overnight from dripping down with no pressure?
Quote from: buswarrior on September 26, 2020, 09:54:50 AM
Richard, is this "uphill" something added on external to the tank?
Happy coaching!
Buswarrior
Here's a photo...
The wet tank is the left half, the dry tank is the right side. Follow the lines coming out of the drain ports on the bottom of the tank. They go uphill a bit and then terminate at the bulkhead. The petcock is on the other side of the bulkhead and accessed through the fuel door.
Even if I leave the petcocks open overnight, there's no way those last few drops are going to find their way out. Looks to me that the system was designed to allow the liquid to collect in the lower portion of the drain tubes and then rely on air pressure behind it to expel everything out the petcock.
And yes - this is all factory. This is the HVAC bay immediately rearward of the main passenger door. (My batteries are in the rear next to the radiator)
Im referring to air tanks UNDER the coaches and under drivers compartment. Since your tank has a valve at the end of the line, any oil will accumulate an the line and be expelled when you open the valve. Same idea, dont you think?Anyway, get an air drier. Keep what you have in better shape.
Btw, my other 4905 has PP valves for expelling any moisture. they are normally closed. Push to expel.
Thanks for all the comments everyone, I decided to just replace with a Bendix DV-2 as I have an air dryer, and the wet tank is up over the axle behind the wheels, so a manual pull type would be awkward, and it would be hard to see what is coming out. I discovered that the Expello Drain Valve comes in two versions. The first versions were pneumatically activated by a small air line from the exhaust port, and the more recent ones are all electronic. They might be nice, but they are three or four times as much, and are more complicated.
I am also a fan of manual drains. I do not like the pull lanyard because they can get debris into them and leak. I put DOT fittings in the drain hole and ran DOT tubing to one of the bays on the coach. I installed 1/4 turn SS valves on the DOT tubing and clear tubing on the exit of the valve to below the coach. The clear tubing allows me to see what is coming out and avoid a shower.
I did this for the wet tank, both brake tanks and the auxialliary ping tank.
Thank you for these suggestions on ways for draining the AIR tanks. Excellent idea.
Is the drain valve also a pressure relief?
Jim
I do believe that any time you are draining a tank...to any degree,
you are relieving pressure.
Quote from: Jim Blackwood on September 29, 2020, 10:32:23 AM
Is the drain valve also a pressure relief?
Jim
I don't believe that they all are. I've seen types that have a preset limit and then they pop, but on my bus I don't think that they do that. Three of my five are petcocks, so for sure they are not a pressure relief.