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Topic: Desiccant in air system  (Read 1132 times) previous topic - next topic

Desiccant in air system

My search indicates that this is not a new topic. Due to my own neglect,  I too found desiccant in my air system. The two front air tanks had less than the rear air tank. Jack Bradshaw replaced the air dryer and recommended that I buy and carry a ride height control valve and a leveling solenoid (six pack valve). He recommended that I open the tank valves after EVERY day of travel.  He did not recommend a massive overhaul or purging of my air system (like Jim McNeece's post from three years ago indicating that he did).

A complete cleaning like Jim did would contribute to a better night's sleep. But, I do not have the tools nor skill for the first rate job that Jim did.

From reading previous ForeForum posts, the consequences of desiccant in the air lines is to clog the valves one by one until they fail and or become unreliable.

So I am asking what my best course of action might be. Carry extra valves and replace as needed or proactively get the system cleaned up. I favor the cleanup and therefore wonder where? MOT or FOT.
We are living in our motorhome in Mission, TX for the winter and are less than 600 miles from Nacogdoches. Of course, this assumes we can even get to Nacogdoches. Before leaving I plan to run the engine and hopefully get some more powder from the system by opening the tank valves. 

I feel I should at least get the recommended valves and was wondering where to order from (and how to find the correct part numbers).

Thanks

Bob
2000 U270
Winter: Texas Rio Grande Valley or Foley, AL
Summer: The Gardens RV Community of Crossville, TN
2000 40 FT U270, Xtreme FBP
2017 C-Max Towed

Re: Desiccant in air system

Reply #1 –
Bob, there are a lot of valves in the air system on a Foretravel so carrying one of each may be an expensive option. Not to mention finding and changing them. If it where me I would have someone clean the main air tanks and lines between them.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Desiccant in air system

Reply #2 –
I was worried about the same thing so I replaced the complete dryer with a AIR DRYER ASSEMBLY - MERITOR WABCO SYSTEM SAVER 1200 SERIES R955205 STYLE | eBay  This is an aftermarket unit but the quality is excellent and you can't beat the $109 price. Wabco no longer manufacturers the unit in Germany but outsources it to Poland so I didn't feel bad with the Asian knockoff.
I used an old steel plate to adapt the dryer to the coach and moved it slightly to the left for easier access. The existing hoses won't quite reach but the extra fittings were only about $7 each (2 required). It does pay to purchase a "crow's foot" to loosen the fittings on the old dryer before removing it as they can be very tough to break loose. Once they have been loosened the first tiny bit, they are easy to spin off by hand. I used a Radio Shack box to make the connections. Either wire can go to hot or ground. A spare spin-on is inexpensive and only takes 30 seconds to remove. Easy to pull the cover off and check to see if power is there. Screw that fastens the box to the coach provides the ground. Photos below.

Jerry is the expert on coach air compressors now so contact him or perhaps he will post what problems/solutions he has found on rebuilding the head, etc.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Desiccant in air system

Reply #3 –
 Well this brings me back to my comments re the changing of the Dryer Desiccant etc parts on a regular 3 yr cycle.  This is possibly the most changed item on our coach since buying it. I have just done it again since Nov 2013 total rebuild.
Barry "Beam" a few years ago had the same problem of the "white stuff" getting loose and he has taken apart every line and valve a few times along with washing out the tanks too and is still having some issues with it. I believe there is no way around taking the same route as he in that everything has to come off and be cleaned out. It will cost many CB I assume at one or the other place I would think.
Sorry to say this but anyone NOT changing out the Dryer on a regular basis is playing with fire, and very expensive flames!!
JohnH
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Desiccant in air system

Reply #4 –
Quote from: Pierce & Gaylie Stewart –
Jerry is the expert on coach air compressors now so contact him or perhaps he will post what problems/solutions he has found on rebuilding the head, etc.
Pierce

Pierce,

You flatter me too much!  I only tried to follow up on the great work you and Chuck did on your air systems.  I was getting a lot of water (no desiccant)  and all three tanks were going down too fast.  I also found no evidence that my dryer had ever been serviced since new!  All of this lead to the discovery that the compressor was not unloading and running all the time!

After seeing what Chuck did I decided to follow his lead and replace the check valves and protection valves first.  After struggling through that process it worked out so well I decided to take on the dryer.  Upon removing the dryer (Bendix AD-4) and using a bypass I found that the compressor kept building air,  the governor was working and there were no major air leaks.

Removing the intake hose from the turbo I realized the compressor unloader valves were stuck open and the compressor was running all the time and never unloading. They were rusted and frozen up so bad and I couldn't even break them loose with pliers and  PB Blaster!  Years of air dryer neglect and the coach sitting up for long periods probably lead to this situation and as John H has noted could be very costly!

After struggling through that, I ended up having to install a field maintenance kit ( intake and discharge valves and springs)  on the compressor head.  I have the Bendix Tu-Flo 501 compressor and in order to install new unloader valves you have to remove the compressor head.  Fortunately, you can change the unloader valves on the newer models without having to remove the head.  Should take about five minutes!  If you have to service the head the kits come with all parts needed including gaskets.  Be careful with the head bolts not to snap one off.  I soaked mine with PB Blaster and carefully broke them loose.  Be sure to torque the head bolts to specs for re-assembly. 

Since I had never done it before I decided to rebuild the air dryer after I found all the necessary parts at a local truck parts place.  I'll keep this one for a spare (It's obsolete)  and replace it with an upgraded model in the future.  Be sure to test for leaks with soapy water ( I use a spray bottle with Dawn liquid) and make sure all is working correctly. The maintenance guide for your particular model will give you all the info needed.   

Doing all this work to the air system is not a difficult job but it will test your patience so be prepared.  As these coaches age or without proper maintenance it will become necessary.  Having the proper tools will make the job much easier and you'll be satisfied in a DIY project that will save many CBs. 

Jerry
The selected media item is not currently available.
Jerry and Cindy Maddux
1993 U300/36WTBI DD6v92TA
build 4271  "Miss Lou"
1995 suzuki sidekick 4x4 toad
Gulfport, Ms

"Pride of Ownership"

Re: Desiccant in air system

Reply #5 –
Our coach air system was neglected as well... replaced a bunch of valves and replaced  the complete air dryer system, now just draining all air tanks twice a day when traveling and twice a month when parked. hoping for the best...
'02 40' U320t  4010WTFS Build 6036 1 slide
Motorcade # 17841
SKP 151920
Retired truck driver
 5 million miler
Still have itchy feet for travel

Re: Desiccant in air system

Reply #6 –
Lot said about this as all note....one caution.  I did all this over and over once contaminated.  we finally found the critical path...remove and clean out or replace the wet tank.  It was a continuing source until that done.  Trying to wash it out in place did not work.

May not apply to you but fought this for 18 months replacing a check valve now, a solenoid there, repeat again after another month or two until really got rid of the source.

Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches

Re: Desiccant in air system

Reply #7 –
Looks like we may have to go the same route and replace the wet tank,,,,getting desiccant when draining the (wet) tank.
bummed
'02 40' U320t  4010WTFS Build 6036 1 slide
Motorcade # 17841
SKP 151920
Retired truck driver
 5 million miler
Still have itchy feet for travel

Re: Desiccant in air system

Reply #8 –
Replacing the wet tank  shouldn't be that big of a bummer. I would hazard that foretravel didn't make a special tank rather than use one they could purchase easily and I bet it is a lot cheaper than chasing valves and solenoids.
Toby a 94 u280
Cummins 8.3
6 speed Allison
Exhaust brake


Adopted by Derek and Annabelle

Re: Desiccant in air system

Reply #9 –
I agree with Toby that they are most probably a standard tank, maybe just the placing of the NPT welded on fittings. Tanks are mostly 12" dia and 15" long. That is what mine are and all the same. Should not be more than around $100 looking online at others complete with pipe fittings.
JohnH
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Desiccant in air system

Reply #10 –
Most truck supply shops have a reference book that you can look up all the different configurations of fittings and tanks.
Toby a 94 u280
Cummins 8.3
6 speed Allison
Exhaust brake


Adopted by Derek and Annabelle

Re: Desiccant in air system

Reply #11 –
Most radiator shops clean gas tanks why not check them out?
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Desiccant in air system

Reply #12 –
MOT tried to clean with some chemical wash first.  A new tank was later said to be $150.....still bugs me I did not start there instead of replacing parts, hoping as each part was repkaced that we were done, that all the dust had all worked thru the system when in fact more was on the way! 

Funny in hindsight, overlooked the obvious or we just hoped without understanding that it was not minor, just one more part and be done!  Not!

(Been a while, think it was CLR used to clean after tank was taken off the coach)
Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches

Re: Desiccant in air system

Reply #13 –
The radiator shops use an acid then neutralize. I have used 3'8" nuts in motorcycle gas tanks to remove rust. Put in a couple of handfuls then add soap and water and shake and repeat until rust stops showing up.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Desiccant in air system

Reply #14 –
Quote from: BobW –
My search indicates that this is not a new topic.
Bob has probably already seen this old thread, but for those who have not, it paints a graphic picture of "white dust contamination".

Air Dryer desiccant contamination creates symptoms of air leak (split from...

Any (new or old) Foretravel owners who are not aware of this potential problem should "read and heed".  Prevention (regular air dryer service) is MUCH preferable to (expensive and time consuming) recovery after the fact.

In the OP's case, I vote with the "replace the wet tank" group.  Small cost now to avoid major hassles down the road.

If anyone locates a good source for a replacement wet tank, please post in the "Part Number" thread.


1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Desiccant in air system

Reply #15 –
I have cleaned and "reconditioned" rusty fuel and compressor tanks so they are like new with not much work. After determining that there is no longer any "white dust" in the tank, just some rust, pour phosphoric acid (muriatic acid in badly rusted tanks) into the tank (after cleaning with a soap/TSP solution), changing position every few minutes until there were no traces of rust left. After the tank was dry, I have poured a fuel tank slushing compound into the tank, rolled it over until the interior was completely covered with the compound, drained the excess and let it dry. It forms a protective plastic coating that keeps any moisture away from the steel tank shell. Here is a source: Aircraft Spruce from Aircraft Spruce  You probably won't be able to ship the slushing compound into California because of ARB regulations.

Note: while not a problem with air or diesel, pump gasoline with alcohol may damage the compound.

On an eight day trip from Hong Kong to Manilla, salt water in the bilge of our sailboat ate holes in the diesel fuel tank (new boat, new tank). After bring the boat back to the states, I pulled it out, welded plates over all the sides where the steel had holes, used muriatic acid on the inside and used a couple of quarts of slushing compound on the interior. After cleaning the exterior, I coated the tank with epoxy resin over several layers of fiberglas cloth.  No way for the diesel or salt water to contact the steel. Never a problem after that.

Formosa Boat used stainless for the water tanks but even after repeated requests, would not construct the fuel tank with anything but mild steel plate.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)