Air tank lanyard valve question

[WEC4104]

Sit back guys... It's silly question time!

The standard drain valve on my 4104's rear air tank is pretty buggered up and I've decided to replace the valve. In the meantime, I came across a brand new tank, so I decided to do both at once.

In considering my drain valve situation, I have noticed several discussions on the lanyard pull-cord style, which would make the draining process a lot easier.   Easier is good.

A recent thread mentioned Napa as a source for these, and I swung by and picked one up. The package says Haldex KN21004, but I don't have the Napa receipt and their part number in front of me. The photo below shows the item, and it has about a 3 foot cable attached.

I pulled it out tonight and started looking at it, thinking I would get started by attaching it to the tank. Playing with it, I held the valve in my hand and pulled on the cable. It didn't budge. However, I can push in on the little stem, in the direction of my yellow arrow.  Huh, isn't that backwards?

I was picturing the valve at the bottom of the tank with the lanyard dangling below. Pull down on the cable and the tank drains, no?   I guess if I pull sideways on it, it breaks the seal a little, but it doesn't seem like it would drain right to me.

I thought maybe it needs to be under pressure to operate properly, so I threaded it onto the end of my air compressor line.  Nope, the stem wants to be pushed in to let air/water escape.

So guys, is my thinking bass ackwards, or did I purchase the wrong part?

[bobofthenorth]

No - you've got the right one - identical to the three that I installed about a month ago.  I was confused by exactly what is bothering you too.  You don't pull out on the stem but rather deflect it sideways.  And a surprising amount of air will come out when you do that.  Just run the cable over to the side of the bus somewhere that you can easily get hold of it to pull and it will work fine.

[BUR]

Just what Bob said. The only word of caution I have is where you route your cable. In snowy and icy conditions I have had ice build up on the cable and dump my air going down the road. Not really something you want to deal with in a blizzard.  PS they work great.   BUR

[WEC4104]

Thanks guys.  As always, this board is a never ending source of answers.

[buswarrior]

Think of the inside of that part where the cable attaches as being T shaped. It seals on the bottom, under the armpits and when you pull sideways, you tip the T so the air sneaks out under the side closest to the direction of pull. The piece is really round, like an intake/exhaust valve out of an engine, but easier to describe in two dimensions.

The air pressure makes it seal tighter, by pushing on the top of the T.

Excellent question, as they aren't immediately intuitive at all!!

happy coaching!
buswarrior

[gus]

To say it another way, the drain valve is designed to point straight down and the cable to be pulled to the side.

I run my cable into the front left wheel well using wire clamps as cable guides/holders.

[gumpy]

I ran mine into the wheel well's also, and attached with stainless/rubber cable clamps. I can reach in and pull the cable. I did have some ice build up on it in the blizzards we were in last March in Wyoming, but it was not enough to open the valves, but certainly something I will be aware of should I ever find myself in those icing conditions again (hopefully never again).

craig

[gus]

I was only in icing conditions once and I parked then so having the cable in the wheel well is no problem. I just sit in my cozy bus until the weather improves.

I don't drive the bus in ice or snow, I'm too old and smart for that nonsense.

[Gary '79 5C]

I just installed the drain valve with lanyard, Started up after oil change and conversion to spin on filter. I figure I will blow down after 20 minutes of operation and nothing. I pull from the side, and straight down nothing. I try again, nothing.

Good thing no one else was around, as I again pulled the lanyard, but this time more assertively, and Voila, just as designed. What a weak wristed, funny person I was up to that point......

I am glad that this has the resistance it does to insure I do not lose air going down the road from this valve. I know it was designed for this service, but out of the box it seemed to have much less resistance.

Thanks to Bob of the North, and others for the recommendation.

Gary

[zubzub]

Did you buy a new one off the shelf and if yes do you have the info on the replacement tank you installed I would be interested.  I need to change mine and the bus is a bit far away.  Basically any and all info appreciated, as going out to pull the tank and then ordering it will make it a 2 day job instead of one (aren't I optimistic)

[Gary '79 5C]

ZZ,
I did not replace a tank, despite my slightly run-on post. I only replaced the valve on the first blowdown after the compressor. The valve was not a stock item at my closest NAPA, but they had same in 4hrs, close enough.

Not sure I have helped ?

[Ed Hackenbruch]

I just bought 4 of the drain valves but have not put them in yet, got other things going on this week.

[johns4104s]

On the MCI 9 mine all leak. I found the manual one work better on the 4104. You can release them with a pole and hook without getting under the bus. I replaced the rear one ( which never worked right )with a value.

John

[BG6]

Just what Bob said. The only word of caution I have is where you route your cable. In snowy and icy conditions I have had ice build up on the cable and dump my air going down the road. Not really something you want to deal with in a blizzard.  PS they work great.   BUR

Before taking a trip in those conditions, I tend to spray WD-40 on anything that I don't want ice to build up on, including the chains on the air drains.

[gus]

BG,

Good idea, I never thought of that! However, I don't drive in icing conditions if I can avoid it.