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2003 U320 - Phase 3 of Desiccant Powder Cleanup

December 21, 2013, 11:03:20 pm

Today I cleaned the front HWH manifold, solenoids, and some of the air lines running from the front brake tank.

As expected, the solenoids all had desiccant powder in them and all of them leaked on my test jig.  Photos 1 and 2 show a couple of the the worst looking solenoids, but all looked nearly as bad.  Photo 3 shows the test jig where all the solenoids were tested before and after replacing the plungers.  All were tested to 120 psi which is 2x the front manifold pressure regulator setting.  None of the solenoids showed any leakage with the new plungers.

All the passages in the manifold were cleaned with compressed air and with a large diameter pipe-cleaner-like thing I found in the crafts section of Walmart.  Kind of like a 1/4" diameter fuzzy caterpillar about 18 inches long (I think you are supposed to bend them up into giant spiders).  Got lots of desiccant out of the manifold.  I replaced the two check valves with new ones.

Several lines from the front tank were cleaned by blowing them out and swabbing with the fuzzy caterpillar attached to a long piece of wire.  The worst line was #55 which runs to the height control valve.  Photo 4 shows the pile of desiccant swabbed out of the 2-ft long piece of 3/8" air line.  I shudder to think how much desiccant is in the rear HCV line that runs the length of the coach.

Everything is back together and leak tested. 

The rear manifolds and lines from the other brake tank are yet to be done.  Maybe next week.

I spent about 5 hours under the coach today.

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Re: 2003 U320 - Phase 3 of Desiccant Powder Cleanup

Reply #1 – December 22, 2013, 07:12:18 am

You guys are scaring me with this problem. I think I'm going to change my whole dryer to a turbo 2000. I have worked on railroad equipment for many years and never have seen this problem. Looks like a project for Tybee Is. next week. They have a much larger filter any way. This maybe why my HWH is erratic.

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Re: 2003 U320 - Phase 3 of Desiccant Powder Cleanup

Reply #2 – December 22, 2013, 07:56:50 am

Interesting, Jim!
I took my coach to the trucking maintenance that usually works on the coach for oil changes and the like. They said they never removed or cleaned their dryers.

I mentioned this to the tech at TN RV; he took a look and promptly removed and replaced the dryer - said there was a bulletin out on what I had.

So much for letting the trucking company work on the coach!

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Re: 2003 U320 - Phase 3 of Desiccant Powder Cleanup

Reply #3 – December 22, 2013, 10:37:36 am

Mine still has the original pure air plus air drier on it. It gets a complete overhaul every 3 years,although parts are getting harder to find and a little pricey $200.00 for a complete kit . Might be time to change it out to something newer.

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2003 U320 - Final Phase of Desiccant Powder Cleanup Completed

Reply #4 – December 26, 2013, 10:19:27 pm

Continuation of Tread 2003 U320 - Phase 2 of Desiccant Powder Cleanup Complete

Spent a long day under the coach completing the air system clean out.

Took all the solenoids off the 2 rear manifolds and replaced the plungers on all but the two tag dump valves (these have large diameter orifices and the plungers I found won't fit).  I just cleaned the dump valve plungers and reused them.  They did not leak since they never have pressure on the "face" of the solenoid.

All the other 10 solenoids leaked when I tested them on my jig.  In looking at the plungers, the leak seems to result from impressions made in the seat material and not from the desiccant powder.  The indentations from the orifice on the seat material was significant on all the valves.  To me, this means that if you have a 2003 Foretravel, you probably have leaky solenoids whether you have a desiccant problem or not.

There was not nearly as much desiccant powder inside the rear solenoids and manifolds as compared to the front ones.  There was, however, a large amount of desiccant in the air line running from the front air tank to the height control valves.  When I blew it out with 150 psi air, there was a large white cloud at the rear of the coach.  It took about 6 or 7 blows before there were no more clouds.

Ok, so all the components are cleaned, but that is no guarantee that the system as a whole will perform well.  I'll just have to wait and see.

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Re: 2003 U320 - Phase 3 of Desiccant Powder Cleanup

Reply #5 – January 16, 2014, 09:02:59 pm

It's been 3 weeks now since I finished cleanout of the air system and replacement of the solenoid plungers.

So far everything works just fine.  I can level the coach and turn off the leveling system and level does not change.  I use a bubble level on the kitchen sink and the bubble does not move a hair width in a week (I've never left it alone for more than a week as there is always some reason to raise the coach and work on something).

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