Another Haldex air dryer failure

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Another Haldex air dryer failure

April 22, 2015, 04:10:04 am

Or perhaps I should have said another owner failure to replace the desiccant cartridge in time...

Anyhow, finally got around to checking the desiccant cartridge and found the dread white dust at the bottom. Checked records, and I last replaced the desiccant and coalescing filter 3.5 years ago. The air dryer has never been replaced as long as we have owned the coach, but I did do a rebuild when I replaced the cartridges.

Clearly, I will be changing the cartridges every year now!

So off to NAPA, ordered a Haldex-remanufactured one, and then started removing the old unit. The outlet air line (to the wet tank) was only a mild pain to remove, but the inlet (discharge line from the compressor) was really hard to remove, and I finally had to use a torch on the fitting (water soaked rag on the hose side, etc.) to get it off, and very happy I didn't have to do it on the road. There was white dust in the outlet line to the wet tank, which I scrubbed out with a rag on a fish wire, and then blew out with a compressor, and was able to blow some dust out of the wet tank, but as others have reported, I never saw any dust come out of the wet tank remote drain, which I check weekly. I replaced all of the check valves on the three tanks, and saw some dust on them, and in lines, so assume I will be finding and eliminating it for quite a while, but thus far, no operational problems, and leveling seems to be fine both on ride height and HWH leveling while parked. I do have a leakdown from 120 psi to about 40 psi overnight, and will be chasing that later, but that's apparently within spec for truck air systems.

Re: Another Haldex air dryer failure

Reply #1 – April 22, 2015, 07:58:21 am

Air dryer and turbo - tough week! At least you guys have a beautiful coach to live in while you get stuff repaired. Good luck.

Re: Another Haldex air dryer failure

Reply #2 – April 22, 2015, 11:23:26 am

Dave, I bet most of your air leak is from the floor slide step cover. I did the solenoid addition to fix this as you will have a tough time replacing that cylinder without being able to stand underneath. It is a cheap cylinder and non fixable. I would suggest doing what I did adding the NC solenoid to that 1/4" air line behind step box.. This made a massive difference to our leak down rate which now takes at least 4 days to get down to 90lbs.
JohnH

Re: Another Haldex air dryer failure

Reply #3 – April 22, 2015, 12:38:22 pm

This is quite a quandary, as quite a few are finding white powder even though periodically changing the desiccant filter.

I used to think that white powder syndrome would be a side effect of not changing desiccant in the last 5 or more years. Wonder if Haldex has a quality control problem? I would think that the white powder would be contained within a working filter and the need to change other parts of the air dryer would have little to do leaking powder.

Repairing or installing a factory rebuilt air dryer would be needed if we could not build air pressure, etc.

One over the road trucks must run their engines more than 3-1/2 years of RV driving.

And we are told that as long as we don't see moisture and white powder when opening the wet tank drain, the dryer is ok.

We are joining the Dave&Nancy program and will change the two filters every year from now on. Just remember to dump air before trying to turn that big filter.

Re: Another Haldex air dryer failure

Reply #4 – April 22, 2015, 01:04:45 pm

Know this has nothing to do with white powder, but John's recommendation to put an air shutoff solenoid on the step slide is a good idea and much easier than replacing a leaking cylinder. Cylinder seals must leak from having air pressure on them all the time, as long as the air tanks have pressure.

Adding a 12-volt shutoff will fix a leaking cylinder, but it would also help prevent a cylinder from starting to leak by only having air pressure in the cylinder for the moments of open & close. A 2-way valve would keep air pressure in the cylinder, even when the air is turned off, but using a 3-way valve would immediately dump the air every time the 12-volts is turned off.

Re: Another Haldex air dryer failure

Reply #5 – April 22, 2015, 04:07:53 pm

Found my haldex and it has a small drain on bottom of filter. , do I open this to allow water out ??

Re: Another Haldex air dryer failure

Reply #6 – April 22, 2015, 11:20:00 pm

Quote from: Jimmyjnr – April 22, 2015, 04:07:53 pm

Found my haldex and it has a small drain on bottom of filter. , do I open this to allow water out ??

No, there should be a remote drain for the wet tank which is hand operable and totally separate from the dyer. On ours (99 U270), it's in front of the drivers side rear wheel. Look directly in front of the wheel for a hand operable valve with a 1/4" tube connected. Not sure where it is on an 03 U295, but one of the 03 owners should be able to point you in the right direction. Nothing on the air dryer is a manually operated drain, and if you choose to replace the cartridges (both on top of the dryer), you will need to open that drain to let all the pressure out of the wet tank.

Here's a picture of the air dryer used on our coach:

http://epi.hbsna.com/products/dept.asp?msi=0&sid=D2DE32737BCE4090895E930C5BA09A2B&dept_id=109&parent_id=0

On ours, it's at the back of the engine compartment on the right, and visible when you open the engine door.

Re: Another Haldex air dryer failure

Reply #7 – April 22, 2015, 11:35:41 pm

Thank you Barry for noting it is a good idea and a lot easier and cheaper than messing with that cylinder. I agree on your 3 way but as I put the 2 way on and the seals are leaking anyway on cylinder I do not have any trapped air in cylinder to worry about, but you are correct.
I was able to get to that cyl' by standing in the pit and with Genset pulled out. It really is a b---h of a job and honestly if you are going to pay FT to take it out and replace with another one, then I say anyone doing this has money to throw away. It is a simple matter to do the valve install and helps greatly with the leakdown air loss retention.
JohnH

Re: Another Haldex air dryer failure

Reply #8 – April 23, 2015, 12:34:57 am

Dave, if you review my travails with dust, it caused numerous check valve and regulator replacements, solenoid problems. Over a year to fully resolve. (My coach will now sit three weeks and psi still above 40.)

One major flaw in thinking was on the wet tank. We should have early on removed it and cleaned!

We got dust to cease coming out the wet tank drain after replacing downstream parts and cleaning the tank while connected. But before long, problems returned. Mr Risch then decided to remove the tank and clean it some other way.....when off the coach, air blown thru it, the ensuing dust storm filled the bay atmosphere.....lesson learned, that tank not really cleaned until removed, cleaned with air and then some type of clr solution.

My experience, yours may differ....but i could have saved a lot in my case if had just really, totally, cleaned that tank the first time or even just put a new tank on. Instead we wrongly thought it clean by accepting the lack of dust, after some other cleaning efforts, as a sign that we had really resolved it while still installed. In fact we went for some time with no dust out the drain valve, the bang it back...in truth it never left until removed the tank to ckean. Haldex in hind sight i think said that would be the case.

I check now after any, any, driving.

Re: Another Haldex air dryer failure

Reply #9 – April 23, 2015, 12:55:49 am

Yep, may have to drop the wet tank and clean it with soap and water, but that will be this summer, I think. No time now.

Any idea what a new tank costs?

Re: Another Haldex air dryer failure

Reply #10 – April 23, 2015, 10:27:48 am

Quote from: Dave Katsuki – April 23, 2015, 12:55:49 am

Any idea what a new tank costs?

Dave,

The last one we got for someone was ~$125 from Truck Parts World. (they are a local company for the oil field) You could look at Ryder if you are not in a hurry and can wait for shipping time. The mounts were slightly different but were able to drill new holes and they were good to go.

Pamela & Mike

Re: Another Haldex air dryer failure

Reply #11 – April 23, 2015, 10:40:17 am

Dave, i really do not...but a tech told me about $150. Anyway i said, why did we not just do that?.....we spent much much more chasing the problem at the wrong end before getting back to the source at the beginning.

To reiterate though, techs thought the tank no longer the source after the work to clean it in place, using a procedure by haldex. We also tolerated dust after that impacting downstream devices, thinking it was from old dust just in lines or front tanks that would have to work its way thru. Maybe some was, but clearly the wet tank continued to feed dust into the system

Some dust was just caked...lots of it...in the tank, possibly enhanced from the moisture from trying to clean? Only real success on that was when the tank removed and it attacked with the better chemicals. In the check valves you could see how well the dust could adhere to the metal, hard to even remove with a metal scraper.

But even more, when the tank was removed and blown out with air, a large amount of dust blew out that was not caked. I think at some point the drain valve just gets the dust around it and is not representative of the whole tank.

I should have thought better, insisted that that tank be removed, thought that it could still be the source. But i and techs were excited when it stopped, thought that we had the problem solved once the residuals in the lines made it out. Not.

Seems i am offering awkward explanation, probably reflecting still my frustration over those efforts when i should have insisted a more vigorous attack on the reservoir of dust!

Now to what one of you asked? What is the root cause of this dust getting into the system? It seems a new problem.

But I will say, that when i first posted on this some time ago, one owner told me that it led to him opening the wet tank drain valve and a slurry ran out! Some wrote or told me, i did not even know of such a drain valve.

Certainly too many were going for a long time without servicing the air dryer, nothing like annual. That is likely whar happened to me, the PO changed oil and fuel filters but not air.....and that dessicant over time broke down into dust and made it out and into the wet tank and on down the lines.

Dave, not what you asked, has become more a plea...owners, especially newbiees, need to know of this.

Mike

Re: Another Haldex air dryer failure

Reply #12 – April 23, 2015, 10:47:33 am

I am mystified by the number of air dryer problems on Motorhomes. Seems to me that in over the road use that these would be more prone to failure with the CONSTANT stream of wet air flowing thru the dryer. Yet I don't hear from truckers that I know that dryers are a problem. Now that I read this maybe that is the answer, with a CONSTANT flow of wet air the desiccant tends to accumulate water and expel it more often thru the purge valve where on a MH the water may tend to collect in the desiccant and not be expelled leaving it water logged and not able to dry out. I dunno, seems like the dryer should operate for longer periods without service. Just my rambling.
Gary B

Re: Another Haldex air dryer failure

Reply #13 – April 23, 2015, 02:51:31 pm

Dave
Found the three valves in DS wheel well do I just slowly open to let any water escape ?

Re: Another Haldex air dryer failure

Reply #14 – April 23, 2015, 02:56:21 pm

Yes, open them slowly.

You should get ZERO moisture, dirt or white powder. Just clean, dry air.

Any of the above indicate a failed air dryer.

Re: Another Haldex air dryer failure

Reply #15 – April 23, 2015, 03:07:09 pm

Thanks Brett
Will try that now ( should I also be looking for a forth valve ? )

Re: Another Haldex air dryer failure

Reply #16 – April 23, 2015, 05:13:28 pm

Have all the failed, air dryers been Haldex? Has anyone with the Bendix AD 9 had this problem?

Jason

Re: Another Haldex air dryer failure

Reply #17 – April 23, 2015, 07:01:16 pm

Brett ,
Opened each valve , dry clean air .
Problem averted
Thanks to you guys

Re: Another Haldex air dryer failure

Reply #18 – April 24, 2015, 11:11:45 am

Quote from: jerrett – April 23, 2015, 05:13:28 pm

Have all the failed, air dryers been Haldex? Has anyone with the Bendix AD 9 had this problem?

Jason

I wondered the same thing about the reliability of Haldex vs Bendix. I also wondered about any differences between the AD4 and the AD9 as I believe my 93, U300 has an AD4 dryer. Being 22 years old I was thinking of putting on a new dryer but now I am reluctant to do so. This goes back to what I've learned having a vintage motorhome, "If if ain't broke, don't fix it" because you will break something else during the replacement.

I have been unable to locate a NEW Bendix AD4 and don't think I want to put a Haldex on my coach. Anyone know where I can get a Bendix AD4?

Re: Another Haldex air dryer failure

Reply #19 – April 24, 2015, 11:25:28 am

Kent,

The AD-9 is a direct replacement for the AD-4 (same connections). I would go with a Bendix factory (not aftermarket) reman AD-9.

The only difference you MAY have is the short pig tail for the dryer heater.

Re: Another Haldex air dryer failure

Reply #20 – April 24, 2015, 11:35:50 am

Brand new Bendix AD-9 with 2 day delivery for $199, no tax/free shipping at: Brand New Genuine Bendix Ad 9 Air Dryer Free Shipping AD9 | eBay

You could put a kit in the old one but at $199 new, no hassle, just install.

Pierce

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