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Author Topic: Air tank lanyard valve question  (Read 3500 times)
WEC4104
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« on: June 19, 2009, 08:17:53 PM »

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?
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bobofthenorth
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« Reply #1 on: June 19, 2009, 08:37:49 PM »

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.

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R.J.(Bob) Evans
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BUR
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« Reply #2 on: June 19, 2009, 09:09:00 PM »

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
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WEC4104
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« Reply #3 on: June 20, 2009, 06:26:36 AM »

Thanks guys.  As always, this board is a never ending source of answers.
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buswarrior
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« Reply #4 on: June 20, 2009, 08:00:42 AM »

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
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gus
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« Reply #5 on: June 20, 2009, 09:43:45 PM »

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.
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PD4107-152
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« Reply #6 on: June 21, 2009, 05:28:33 AM »

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
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gus
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« Reply #7 on: June 21, 2009, 01:08:33 PM »

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.
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PD4107-152
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Gary '79 5C
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« Reply #8 on: July 04, 2009, 03:38:33 PM »

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
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« Reply #9 on: July 04, 2009, 03:58:32 PM »

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)
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Gary '79 5C
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« Reply #10 on: July 05, 2009, 12:44:32 AM »

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 ?
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Ed Hackenbruch
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« Reply #11 on: July 05, 2009, 06:29:58 AM »

I just bought 4 of the drain valves but have not put them in yet, got other things going on this week. Smiley
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« Reply #12 on: July 05, 2009, 08:15:27 AM »

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
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BG6
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« Reply #13 on: July 05, 2009, 08:17:37 AM »

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.
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gus
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« Reply #14 on: July 05, 2009, 01:13:59 PM »

BG,

Good idea, I never thought of that! However, I don't drive in icing conditions if I can avoid it.
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WEC4104
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« Reply #15 on: July 06, 2009, 06:42:13 AM »

Last week, I had the new air tank with lanyard valve installed.  My bus was going in for state inspection anyway, and I decided it to have them do the air tank work.

Before dropped it off for the work, I disconnected the lanyard fro the valve, and installed the valve in the tank.  I told the local garage that I would install the lanyard cable when I figured out where I wanted it.  Right now, I just have a simple 1.25" circular ring (from a key chain) on it.  It is easy enough to get to, I may just leave it that way.

Before I close, I have a big confession to make to the bus gods.   When I first purchased my 4104 I was very much a novice and did not know there even was a wet tank in the rear.  I drained the front tank regularly, but the one in the rear was never touched.   When I did find out about the one in the rear, I tried to open the valve but part of the valve busted off in the process.  It still held air fine, but there was no way to open it.  I drove that way for another two years.  In short, I drove for 9 years and close to 30K miles without EVER draining the rear tank.  Okay, my confession has been registered, and my conscience is clear now.   [It also feels better that I have a new tank and valve installed  Smiley   )
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buswarrior
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« Reply #16 on: July 06, 2009, 07:07:16 AM »

What difference do you see in brake consumption each time you put your foot on the brakes now?

How much "Stuff" did you get out when you finally drained it?

Air drier and/or other drain points that were maintained?

30 000 miles?  Not too bad a distance. Depending on the humidity where that driving took place, maybe less "stuff" than we might expect!

happy coaching!
buswarrior
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WEC4104
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« Reply #17 on: July 06, 2009, 07:48:15 AM »

So far, I've only driven the 4-5 miles from the local garage to my home. So I don't really have much experience with it yet for comparison.  But so far, I'm not noticing any difference. Of course that's a good thing since it wasn't giving me any problems before I had the work done.

I wasn't at the garage when they removed the old tank. I was curious as to how much crude was in the old tank, but I picked it up after hours and I doubt the guy behind the counter would have any idea. I did not get the old tank that was removed.

We are based in PA, and I have had the bus to most of the states east of the Mississippi, so it has seen it's share of humidity.   I was regularly draining the front tank, but never got much of any fluid out of it.  I periodically drain the ping tank in the engine compartment, over the transmission area, and do get some ooze out of it.   The 4104 has no air dryer.

Back about two years ago, in the dead of winter, I had an instance in my driveway where the bus started but would not air up.  It was below freezing, and no doubt the air lines had frozen.  That was the only problem I ever had, and was not serious since I really didn't have any plans to drive any place that day.   Once it warmed up, she was fine.
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« Reply #18 on: July 09, 2009, 07:56:56 PM »

WEC,

I can top that, I drove my 4104 for two years with the rear tank bypassed and with no drain on the front tank!! Talk about dumb, but I finally do learn, it just takes me a while! The brakes worked fine and there was nothing to indicate anything was amiss. I don't think the PO even knew about the bypassed tank.

I discovered the rear tank was bypassed only when I opened the original drain valve, that huge bronze thing, and nothing came out?

Once I replaced the rear tank my system held air much longer - surprise, surprise!

I now have drains on both tanks. I installed an automatic drain valve on the rear tank but it doesn't work, I have to drain it manually. I may just replace it with a manual valve because the automatic one drains from the side and I don't think it drains as well as the manual. Also, the automatic ones can freeze and cause problems if the heaters fail.
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« Reply #19 on: July 12, 2009, 06:42:25 PM »

Put all 4 in today, only took me most of the day. Smiley Had to figure out different ways to attach the lines to the bulkheads to make sure the tires would never catch them. Of course i also noticed several other little things that i fixed or changed while i was doing all of this.......so easy to get side tracked!  Grin
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« Reply #20 on: July 16, 2009, 10:02:37 AM »

Thanks for this poennst guys!

I went out and got three of those valves so now I have one on every tank (already had one on one tank)!

Glenn
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Glenn Williams
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