Air Sytem Drain Lanyards

[Gadget Man]

My owner's manual says to pull on my air system drain lanyards once every six months to drain out any excess moisture. The guy that gave me the walk around at the dealer where I bought my MH last year said once a year was sufficient. He said many owners never drain them and never have any problems.

I just pulled on all three lanyards for the first time. Two of the lanyards stuck in the open position, so I had to crawl underneath the coach and physically re-set the drain pins. I could see no moisture at all on the ground or around the drain pins.

Anybody else experience this?

Craig

[Harry B]

My owner's manual says to pull on my air system drain lanyards once every six months to drain out any excess moisture. The guy that gave me the walk around at the dealer where I bought my MH last year said once a year was sufficient. He said many owners never drain them and never have any problems.

Craig,
I just pulled mine for the first time several weeks ago, since I own the coach as I could not find them (They were buried). Any way finally found them and repositioned them so they are now easy to pull in the future.

When I did pull them no moisture came out along with any one of the three air discharges. So I am also questioning the 6 month frequency. I'll probably do it any anyway now that I can get to them easily, but you do have to wonder.

I also live in Florida yet, where there is not exactly a lack of humidity

[chasfm11]

While I'd admit that there are a lot of safeguards (an input heater, a dessicant filter, etc.) built into the MH air system, almost all compressed air systems will pick up some moisture from time to time. That's why they all have drains. In the case of the MH, if that moisture isn't expelled, it can get into the brakes themselves. If you want to see a really extreme example, there are a couple of episodes of "Ice Road Truckers" that talk about moisture in air brake systems and what can happen as a result. None of us are going to drive our MHs in such extreme conditions but it does get you thinking.

I just figure that pulling the lanyards is an easy thing to do and it is probably a lot like chicken soup and a cold - it might not help but it isn't going to hurt anything, even if I do it more often than called for. A lot of people take small maintenance items like changing their brake fluid periodically for granted, too. I'm sure that there are older cars on the road that have never had their brake fluid changed. For the little bit of time that it takes, I'd prefer to error on the side of more caution, not less. Anything that I can do to keep my brake systems working as safely as possible is a good thing in my book.

[TheRVGuy]

One of the primary reasons that FL sets a 6 month interval is that when we drain by pulling the valves we also get the opportunity to watch for any significant indications of moisture. This is a key indicator that the dryer needs service. Some moisture is not a problem but any repetative evidence of moisture is worth having the dryer checked. This simple check and observe practice is a great way to elimnate some very serious costs involving the entire air system.

If you need further information, you might want to contact Mike Cody of FL. He is an excellent source of info.

Hope this is of assitance.

Mike

[Gadget Man]

Thanks Mike.

Two of my lanyards went to air tanks near the front axle, but I couldn't find where the 3rd lanyard went to. Any advice?

Craig

[jhanan]

Originally posted by Craig P.:
Thanks Mike.

Two of my lanyards went to air tanks near the front axle, but I couldn't find where the 3rd lanyard went to. Any advice?

Craig

On my 2002 XC chassis, the 2 air tanks between the front axle had 3 lanyards. One on the left tank, one on the back of the left tank, and one from the auto-mosture release valve. They did not stick the first time I released them (and you do not pull on them out from the tank as would seem logical, but you pull them down or push them in to release the air). I found a third air tank in the rear in front of the axle, but I did not see a lanyard on that tank (surprising to me - thinking this is where I would find the 3rd lanyard!). On release I did not get any water, so I guess my dryer is working OK (see my other forum question on low air). I guess on the Itasca you cannot pull the lanyard's unless you crawl under the coach. Other than having to crawl on the ground under the coach it was easy to pop the release valves. (Umm-update - yes the pull cables are in the passenger front wheel well right where the manual says! )

Have you changed the air dryer? I looked at my unit in between the 2 rear wheels just behind the axle and it looks very tight to get the filter wrench on it. I would like to replace it myself, but it looks like a difficult job!

Thanks, Jeff.

[Cruzer]

My 2004 Bus/Freighliner had two air tanks but they were partitioned into 5 partitions. The right side tank was a 2 partition tank. The rear portion was the wet, or ping, tank that all of the air initially entered. The forwardmost partition was the front brakes tank. Each partition had a lanyard that extended to the right front wheelwell.
The left side tank had a large partition for the rear brakes as well as two smaller partitions that acted as reservoirs for the front suspension air bags. The rear brake partition had a lanyard extending to the left front wheelwell.

Your air compressor pumps air first to the air dryer. This removes the moisture and then sends it up to the wet tank. After that it goes on to feed the other tanks. Normally the dryer removes the moisture so (unlike the old days) it isn't necessary to drain the tanks regularly. However, your air dryer won't last forever. It'll need servicing eventually (generally 18-36 months, depending on the dryer). By pulling the lanyards you aren't so much draining the tanks as you are testing them. One day you'll notice that the air isn't as dry as it used to be. Then you'll know it's time to service your air dryer.

[Redlands Truck and RV]

Cruzer,

Since compressed air supplies brake pressure as well as suspension air on most coaches I would suggest making draining/inspecting part of any pretrip routine. I like your point about using the drains as a test as well as a maintenance practice.

Also consider that water moisture is not the only enemy of an air system. A compressor going bad will allow engine oil to enter the system, overwhelm the drier and eventually migrate to the tanks, valves and hoses.

Thanks,

[chasfm11]

Jeff, I'm put the air dessicant filter on twice now, the first time as part of a kit with the exhaust valve and input heater cover and the second time as just the dessicant and coelessing filters. It sounds like your chassis might have less space than mine but I was able to get a fairly inexpensive strap wrench that I bought as a set from Sears around mine. The problem for me wasn't getting the old dessicant filter off it was positioning myself to be able to look down inside when I had the coelessing filter off. I had moisture in there and wanted to get it all cleaned out before I put things back together. Hoisting my body around underneath with a trouble light so that I could see what I was doing seemed to take the moves of a contortionist to accomplish. Other than that, it wasn't a hard job (not like replacing the intake air filter).

[Cruzer]

Keith, the air tank draining should be part of a daily pre-trip inspection. Before they had good air driers it was a necessary task to get rid of all the moisture in the tanks. As you mention, there's plenty of oil in there as well. I can't begin to remember how much gray "snot" I've dumped out of tanks in the 70s.

Today's air systems are much better and the maintenance task isn't that necessary. Therefore human nature just tends to skip this because nothing ever comes out. But, it still needs to be checked because some day the stuff will come out and that'll be your signal to service the air drier. I don't agree with any manual that says you need to do this every 6 months. Chances are that in an RV situation it doesn't get used that often so once a month would be adequate. However, if on a serious road trip I'd do it daily. The biggest problem with stretching the interval is that if you forget to do it it gets too far between. If you can fit it into a routine (such as daily pre-trip) it's less apt to get forgotten.

[GI Joan]

I just purchased A 2001 Newmar Dutch star with XC chassis and can't find any info in my manuals to where I drain the air brake. Can anyone help me!!!

[Redlands Truck and RV]

GI Joan,

Some coaches have lanyards customer installed on the 3 air tanks for your system. If you don't see 3 small cables at or near the driver side of the coach then you don't have lanyards. What you do have is an Air Drier with a dessicate filter but after 8 years it needs to be serviced.

A suggestion would be to have it serviced and lanyards installed.

Hope that helps.

Thanks,

[phays]

GI Joan. The air tanks on the XC are between the front wheels. On my '98 Winebago, there is one lanyard coming from the front of the tanks and two from the rear of the tanks. I access them from the right side wheel well. I have to lay down behind the front wheel to access the two rear lanyards but can reach the front lanyard from in front of the front wheel without laying down. I use my awning rod to pull the lanyards. Watch out for dust in the eyes if you are very close to the valves when they are released.

[bdpreece]

I think most motorhome manufacturers never bothered to string the lanyards out so they can be accessed. On my 2004 Freightliner chassis I found all 3 neatly coiled next to the drains.