I recently replaced the check valves (CVs) on the front and rear air tanks. I thought I'd try to revive the removed CVs with a rebuild kit. The first of 4 went fine. It had a little rust that cleaned up OK. Installed the new spring, seat and o-ring. Note that the spring is a little heavier gauge than the original. Photos 1-5.
The remaining 3 were ruined by rust. Photos 6 and 7 typical.
If you open a solenoid and find bits of rust, your CVs might be a place to check.
If you want them to be squeaky clean soak them in vinegar for a few days. The one in the last two pictures may be too far gone to rebuild but you can try it.
Excellent investigative photo report! Good clear close-up photos - make it easy to see how the valve works.
What is the cost of rebuild kit versus a new valve?
I wonder what the inside of your tanks look like Mark?
CLR works great for rust also!
Local NAPA about $28. Rebuilt kit $18. Not really worth the time to do a lot with the old valves for a savings of $10 each, but it was cool to see how they worked. I have a couple of spare rebuild kits :D if anyone wants one PM me.
Let's back up and look at the ROOT CAUSE of the rusty valves (and likely many more components of the air system):
The AIR DRYER had failed. The dryer is one of the more neglected service items on any DP. If you ever see water or, worse, white powder from the wet tank drain, the dryer has FAILED.
Get out your check book.
Wolfe, seems this is one of the most mentioned things on this Forum and should be at the top of the list (in my view) when buying a coach, "when was the last time it had been serviced/replaced"?
We have so much info on the damage it does to a LOT of parts in the system that are VERY sensitive to rust and dessicant and, the time and cost to replace/clean them that this DRYER is one of the most important issues on our coach's.
This thing is in control of so many items that it must rate as maybe the top servicable item on our rigs, and actually is one of the easiest to get to!! It's job is to make sure your brakes work, your levelling system, the suspension, and each of these have a miriad of valves and switches associated with them. Every 2 yrs in my view is when it should be removed and serviced ( any one of you can do it if you want to) and regular checking of drain valves for moisture is as you know one easy way to check for problems. Do all do it,NO.
Just taking out and replacing the "6 packs" because you never thought about this thing will cure you for good as some have found. It is not a nice easy job doing them and could be very expensive to say the least.
Forget about the latest update etc right now and go check the last time this Dryer was done or you may be stuck at the side of the road soon and while waiting for the Tow looking at the nice new LED lights or new upholstry that was more important than this Dryer.
Think about it- seriously!!
I do realise my comments may offend some and that is good, as this is a serious issue.
Marks coach is new to them so they are excused from this rant.
JohnH
Your rants are imformative.Are his check valves the same as the older coaches?
I wonder if alot of the moisture problems come from the aux. air compressor running with its not so great drier?
JohnH, if you only have your air dryer serviced at Foretravel, you are eventually going to be on the side of the road. Why? Because Foretravel never changes the air dryer purge value when they service the air dryer. Why? Because they do not consider the purge valve to be a serviceable part. It is only to be replaced after it fails. Ask me how I know.
I am a firm believer in factory (i.e. the factory that made the dryer) REMAN dryers. Valves, heater, etc are new, as well as filters.
John beat me to it while I was looking back at Mark's earlier posts.
In Mark's case, he discovered, during the PPI, that the previous owner (or the dealer) had pulled the fuse on the aux compressor rather than fix the cause of the aux compressor running too much (or maybe continuously). Then Mark found the aux. dryer system unuseable, from neglect, and replaced it with a superior system.
Brett's point is true and I agree whole heartedly that owner's neglect of the engine driven air dryer tower is the ROOT CAUSE of myriad air system problems.
But in Mark's case, the ROOT CAUSE of corrosion in the three forward tanks was equally or (in my opinion) much more likely due to the uncorrected air leaks which caused the aux air compressor to run to failure, which caused a large volume of air to be pumped which in turn exhausted the small air dryer desiccant system, which then pumped a lot of moisture into the aux tank which also wasn't serviced (drain tested periodically) which corroded the aux tank check valve which then spread the moisture to the front and rear reservoir tanks (and wet tank) all of which were also probably not serviced (drain tested periodically) which in turn rusted/corroded the front and rear tank check valves......AND who knows what else?
Brett and John H are absolutely right that improperly (or worse) unserviced air dryers are responsible for more grief and pocketbook/time drains than owners give them credit for. Don't leave the aux compressor air dryer out of your preventative maintenance routine, though. Because the aux. dryer is small (Mark has done well in improving his design and capacity) it needs to be serviced (at least inspected) several times more frequently than the main engine driven air system dryer tower, depending upon climate and the nature of any uncorrected leaks that you have.
And of course, using a small shop or home or coin operated compressor to air up anything on a coach, including tires, is begging for trouble. People say, "Aww, it's just this one time and I won't hurt anything". Well depending upon humidity and the mass of air pumped, it is probably more volume of water than you imagined. For example, with our coach tires, starting at atmospheric pressure and pumping up to a pressure of 100 psig, 72 degree F air at 70% humidity has over 1/3 cup of water in it. Much better to use known good air or nitrogen or (my preferred choice) a Power Tank, CO2 System. AND, I won't allow a tire shop to put their air in any of my tires, unless they are willing to show me their air dryer system. That's a whole 'nother story on what I have experienced when I made that demand! Usually it's just easier to tell them to only use my CO2, Power Tank. They don't grumble as much.
HTH,
Neal
Neal -- Glad you like the new drying system. I added an input port so I can use my shop compressor during leak checks and testing, but the input port is upstream of the new aux air drying system. Thus any air from the shop compressor should be nice and dry.
Brett -- Appreciate your input. I plan to replace the main Haldex dryer this week.
Mark
I marked up the attachment to show what I suspect has been happening. The check valves in the diagram labeled CV1 - CV4 were all failed (the other 2 CVs on the front / rear tanks were also failed but don't matter for this scenario).
1. The solenoid valve that allows one to connect the aux compressor output to the wet tank input (shown as SV1 on the drawing) was failed in the open position.
2. Because (as Neal reminds us above) the factory aux air drying system had failed, whenever the aux compressor ran, wet air continually fed wet tank (path shown by the red arrow). This happened regardless of the switch position since the SV was failed open.
3. The wet air then followed the normal air path out of the wet tank (shown by the yellow arrows) to the front and rear tanks.
4. The blue arrows show the wet air exiting the front and rear tanks through the protection valves (both of which are interestingly enough working) through CV's 3 & 4 (normal path).
5. Because CV2 was failed, the wet air fed back into the aux compressor output circuit as shown by the purple arrows.
Over and over.
EDIT: Forgot to mention that the air regulator that controls the front airbag manifold pressure also failed with a large leak. Thus there was a constant demand aux air. That too has been remedied.
During the initial inspection the slide out air tank had a lot of water. 2 quarts or more. Since that initial draining, no more significant moisture has been observed during draining even during the drive from TX to GA and it rained pretty much that entire trip. The aux compressor was not used during that trip or since until the new drying system was installed.
As evidenced by the CV photos in the initial post above, I have the chunks of rust on the loose. I thought about protecting the 6-packs and the SO manifolds by installing filters at the three locations indicated. I'd actually install the filters inside the bay next to the new dryer system so I could monitor their condition. But this seems like a stop-gap measure since all the bits and pieces of the brake system would still be vulnerable to rust particles coming through the airlines.
Does it make sense to just replace the tanks?
Thoughts?
I understand what you are saying but, and it is a big one "can you swear to me that ALL factory rebuilt Dryers are 100% correct? in other words was someone having a bad day while doing it and forgot/screwed up something in the rebuild/" Yes I know it is remote but I like to see it myself and know that I have done it right. Also it is good to know how/what they work like.
I forgot to mention the aux comp' as with no slides and me never using it (auto level has never been on) It m,ay as well not be there for me.
Draining the tanks every couple of days is worth gold.
JohnH
Nope, no guarantee of 100%. But substantially higher change of it being correct, than "Bubba" rebuilding with "made to replace" parts of dubious quality or "built to replace" the part number of equally dubious quality.
And, I totally agree, check the wet tank drains-- have always said they were the "report card" on dryer health.
And, yes, with an auxiliary compressor, there are two sources of moisture/contamination.
If the tanks are ASME or DOT they may be expensive. Same size pipe with end caps welded by a certified welder meets ASME standards as does a pipe with removable victalic end caps. Add some thread o let's as required.
The tanks that fit most Unicoaches are reasonable.
Wet tank ~$125
Front & Rear tanks ~$75
Bladder seal tank ~$50
Pamela & Mike
That's way less than expected. Source?
My info shows JWP as the manufacturer.
On a 2003, front, rear, and wet tanks are all showing as 1239, a 12" X 15" Rev B tank. Hopefully P&M can verify since their pricing would indicate a different wet tank.
I'm showing 8001, an 8" x 32" tank, as the slide bladder tank.
These are the tanks only, not the assembly with the fittings.
Michelle,
Thanks for the info on the tanks. Sounds about right. The wet, front and rear appear to be the same although I haven't measured them.
The outside of my tanks are in good enough shape to read the imprinted info. I'll look tomorrow and see if there's a model number. I do recall seeing "DOT" and "150 PSI" on them.
It's ironic that the outside of my tanks are rust free....
Mark, not ironic the inside cannot dry off like the outside and air passing thru gives it perfect conditions.
JohnH
We have a Truck parts world here. If someone swings by and needs one we just go out there and they match one up. (so I don't have a TPW part number) Any good truck shop should have at least a DOT air tank book that you can look a replacement up. These aren't special made for our application they are off the shelf items. If you want to get fancy they are even some made of stainless. The older coaches do have a larger wet tank than I have seen on the Nimbus though so always do a matchup for best results.
One other thought is you may want to get one with at least one extra boss for some use you may dream up.
Pamela & Mike
I'd go one step further. Don't buy any coach unless the PO can prove the air dryer has been changed regularly-in my case every 18 months as the FT maintenance schedule specifies.
Rebuilt my drier last year and used the TWO main kits to rebuild it,this included the purge valve which really needed rebuilding.
Also replaced the check valve on the side of the drier,(don't mean relief valve).Next time will probably get the reman but I now
know how to rebuild.
This thread has me curious about what is a good maintenance schedule for our motorhome air dryers.
I found references to Bendix recommendations like:
For severe service applications, such as residential refuse trucks or school buses, the air dryer cartridge should be replaced every year or 100,000 miles.
Line haul operations using a single trailer should swap the filter out every three years or 300,000 miles.
So severe service recommendation is 100,000 miles and line haul is 300,000 miles, while motorhome use would be gentle service in comparison, such that servicing the Bendix air dryer every 10 years (50,000 miles for me) would suffice.
I wonder if every Foretravel owner who has rust damage inside the air lines has a Bendix air dryer which has not been serviced for ten or more years, or has bad leaks such that the Bendix dryer is always being used to replenish the leaked air.
When I serviced my Bendix dryer four years ago, the old one looked clean and new. Also, I have never seen moisture coming from any of my tank drain valves, not even the wet tank.
I am thinking, five years or 50,000 miles as a service interval would be sensible while never ignoring obvious air leaks.
X2...The same advise was given to me by the PO (who's initials are B.W.). ^.^d
While our issue seems to be more one of rust than desiccant powder, after reading many posts including Mike's reply #12 in this thread, Desiccant in air system (http://www.foreforums.com/index.php?topic=29789.msg254405#msg254405), we decided to replace all 4 air tanks. They are on the way from FOT.
In this thread, 2003 U320 - Phase 3 of Desiccant Powder Cleanup (http://www.foreforums.com/index.php?topic=20032.msg144450#msg144450), Jim recommends blowing out the lines with high pressure air. We'll do that too.
We have a new Haldex dryer that will go in this week -- time and weather permitting -- and our aux air system is tuned up and running well. We also plan to replace the protection valves on both the front and rear tanks and the 2-way check valve on the front tank while we have the tanks out. These OEM DOT-rated parts are cheap and will never be easier to get to than when the tanks are out.
What other recommendations would everyone offer prior to reassembling with the new tanks?
Sounds like you've got it pretty well covered. One thing you might check - see if your Haldex drier is fitted with a "isolation valve". If so, you might as well go ahead and replace it also. It is
not included with a new or rebuilt drier. Shop around for the best price.
KN23500 by HALDEX - Isolation Valve (https://www.finditparts.com/products/368725/haldex-kn23500)
Photo below of the last AD-9 I installed on our coach. Since your coach is newer, it might not have this valve.
Wyatt, I can understand your thinking but as the replacement of the dryer is such a small outlay of money and trouble, I, in all honesty think that when all other things are taken into consideration (ie problems associated with a faulty Dryer) it would be foolish to put this one item of maintenance on the "back burner" for so long.
Even for someone who has to pay a shop to replace it, this cost is equal to a tank of fuel. Is leaving it in, and hoping after 3 yrs that it does not give you grief while on a road trip really worth the saving? When you factor in all the other things we have to maintain on a coach, this one for me is minor, but piece of mind is big.
JohnH
Chuck,
Thanks I will check to see if there is one. I see the part numbers for it on Barry's site.
Your post led me to read more about Haldex dryers and I see that there are several model number variants. The one I picked up on eBay is a model DA33100X. I'm wondering if this the correct one for my coach?
Mark,
Judging by all the rust you found so far in the system you might want to consider doing some maintenance work on the big air compressor. It's usually overlooked and can be a source for internal air leaks and other problems if the inlet, discharge, or unloader valves aren't working properly. When I serviced mine I found the unloader valves were rusted shut and the compressor wasn't unloading and overworking the compressor. Unfortunately I have a Bendix Tu-Flo 501 and had to remove the head to replace the unloader valves. At that point I found the inlet and discharge valves and springs were rusted so I bought a field maintenance kit and replaced them also.
If you have a Bendix Tu-Flo 550 or later model you can replace the unloaders without removing the head which is a royal PITA on a DD6v92. You can also run a leak test with a shop compressor. Chuck inspired me to work on my air system tank valves and drier and that's when I discovered the unloader problem. After all that maintenance work I now have nothing but clean dry air in all three tanks and my compressor builds air more quickly and cycles less frequently.
Here's an excellent instructional video from Bendix on compressor maintenance.
Jerry
https://www.youtube.com/watch?v=VeyFaEP8FKA
Mark,
For a 2003, DA33100X is the correct number for the Haldex reman'd unit yours uses. Now, as for purchasing on eBay, be SURE that unit is reman'd by Haldex, not just any shop or person. That particular number should correspond to a factory reman, but you never know.
NAPA is a good place to get the DA33100X. Core charge is about $100. You get that back when you turn in your old air dryer. Recommend NOT turning it in until you're done installing the new one since you'll need to harvest the fittings from it.
Jim McNeece did a cost comparison a couple of years ago that showed little difference between doing both a major and minor service kit rebuild and getting a Haldex reman from NAPA.
Jerry,
Thanks for the info and the link. I've no idea yet what compressor I have but will dig into it. The video should be super helpful!
Michelle,
Thanks. I got lucky! The one I purchased is actually a NOS not a reman, but since I plan on changing this puppy out regularly I appreciate the info. The forum jury seems to still be out on how often to change out the dryers but there does seem to be agreement that it's pretty cheap insurance, all things considered!!
Chuck,
I just went out back and looked and I do not have an isolation valve. I see some discussion on the forum as to whether an isolation valve is needed or beneficial on the all coach models. Any thoughts on this?
If you are full time, and moving around while doing the drier replacement procedure, be careful about the core charge thing. On our last trip to Oregon, I purchased a reman AD-9 at a NAPA store along the way (in Price, Utah) cuz they had them on sale. The owner of the store was working the desk. I asked if I could return the old (core) drier to any NAPA store, because I was not planning on replacing it right away. He said sure, no problem, as long as you have the receipt any store will take it.
Fast foreward - I finally got around to doing the switch when we got home to Midland, TX. Took the core down to the local NAPA store, and boss man gave me a bunch of grief about taking the core. Said he is only "supposed" to take cores for stuff HE sells out of HIS store. I asked aren't all NAPA stores part of the same company. He says no, they are actually more like individually owned stand-alone part stores that just pay to use the NAPA name and parts distribution network. That was news to me!
Anyway, bottom line he finally took the core and gave me my deposit, so no harm done. Just saying, probably better to return the core to the same store where you buy the reman unit.
No. In fact, I don't really even understand what the isolation valve does. It's above my pay grade. :help:
Same here. From the little I've read so far, it's apparently a form of a check valve.
I bought my rebuilt Haldex at a NAPA store in New Hampshire where there is no sales tax. When I returned here to Tennessee and installed it I returned the core to my local NAPA store where they refunded me the core charge plus the $9.25 sales tax they would have charged if purchased from them.
When I queried them about it the manager told me he had to do it by law.
Mark,
Do you have the link on ebay for the dryer your purchased? I see recondition ones...
Thanks
Charlie
Hey Charlie.
Here ya go: Haldex DA33100X Air Dryer No OE Box | eBay (http://www.ebay.com/itm/222465356279?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT)
This is what eBay shows when I click on my purchase history. This link leads to one that says both re-manufactured and NIB (new in box). The one I received came in a random box but appears to be NOS (new old stock).
Richard barks records showed him replacing the air dyer stuff just prior to our stewardship.
Last winter I had the cummins shop rebuild ours. Five years.
30 k miles. No issues seen
Like others I did the re manufactured unit from Napa and will change filter at 12 months then another reman unit at 24months .
Cheap insurance
When I researched the isolation valve I remember reading that it helped the air compressor run less/unload easier so I changed
mine.Think that info was from Cummins.
After reading BJ Holden's reply #12 in Haldex air dryer isolation valve (http://www.foreforums.com/index.php?topic=17590.msg118355#msg118355), I'm pretty convinced that since we have a 2003 coach, we do not need to add an isolation valve (IV). BJ lays out the compressor / dryer combinations that need the IV and also the back story.
Michelle,
Are you saying that the DA33100X actually indicates that is has been remanufactured as opposed to NOS?
Mark
That's my understanding. Pamela and Mike are likely to know for sure. (and T-man found the info as well :) )
I looked on the Haldx website and cannot find a new Pure Air Plus.
They are all remans.
Pure Air Plus™ Air Dryer - Haldex product category (https://www.haldex.com/en/na/air-dryerair-line/air-dryers/haldex-newremanufactured/pure-air-plus-air-dryer/)
Might check Ebay though they all seem to be remans. I just got one for 200.00, no shipping, tax. genuine part at least it was represented as such and appears to be in a factory box.
Not Chuck, but from what I have been able to glean the isolation valve is only necessary for use with Holset compressors used in the unicoaches until circa 2000 model year. Our coach which has an ISC has the Holset. In any case, it does have an isolation valve.
Don
Air Plus is a discontinued design.
Hasn't been made new for years. All are remanufactured. Buy ONLY factory Reman'd units for QUALITY purposes. Most reman'd have been reman'd many times over. Think garbage truck............times ten.
Forums site search:
Re: On the subject of air dryers (http://www.foreforums.com/index.php?topic=26139.msg208768#msg208768)
HTH
Neal
I'm unsure if an isolation valve is needed on our coach. Searching and reading posts points to "yes" if one has a certain brand & model compressor. Anyone know the answer for the combination of an 03 450HP engine combined with the Haldex DA33100X dryer?
:help:
Mark, the easy way to tell if you need one is to look at the air dryer installed in your coach.
Bill, do you mean to see if our dryer already has an isolation valve? If yes, I have checked and ours does not. If I'm reading older posts correctly, some folks have added isolation valves but I'm not sure if it is needed for the ISM450 / Haldex DA33100X combination.
Mark, if you do not have one now, i would not change the system just because someone said they put one in there system, my dad always told me if I wanted the freshest water go to the head of the stream, in this case it would be James T at FT.
R&R'ed the wet tank and front tank. Harvested existing plumbing bits and pieces where possible.
On the wet tank was able to rebuild one of the check valves, but the other one was frozen so replaced it. Replaced all PTC connectors and trimmed each piece of tubing by approx. 1/4" to remove the previous indentation where the PTC o-ring was seated.
R&R'ed the front tank as well. Wow, it has a lot of connections! Same process as above except I had already rebuilt or replaced those check valves. Installed a new protection valve and new non-return valve.
2 down, 2 to go. If I'm not too stiff, tomorrow is the rear tank and slide out bladder tank.
Mark, bring your coach to our place and put it over the Pit. No sore backs using it.
JohnH
If your able to, a parts list with numbers, would be very helpful to us that may want to do the same project.
Thanks for the pictures.
Good morning, Lon. That sound a like a good idea. I'll get something written up.
Mark
and........ we're done! Got the last two tanks R&R'ed. The rear tank wasn't too bad, but the slide out tank was a bear. The issue was the lack of clearance between the tank and the gen set doghouse. A friend came over and we were able to loosen the doghouse's rear wall enough to be able to pry it out. Thankful he happened to stop by!
Took my home compressor and charged all 4 tanks to 140 PSI and leak checked. Found 2 leaks, one on the front tank and one on the wet tank. The first was a teflon tape application fail. Easy fix. The second was on the pop off valve where the OEM thread sealant between the valve and a reducing bushing failed. Another easy fix.
Here are a few photos of the finished product.
Thanks for all the help and encouragement during this project! ^.^d ^.^d ^.^d
Mark
Beautiful installation! Will certainly help avoid future air system problems, PLUS provide some much welcomed "peace of mind". Well done!
Let's see...figuring a "professional" labor rate of $100/hr (if you're lucky), you probably saved enough cash to buy yourself a nice cold drink!
Happy 4th of July!
Nice job, Mark.
Brett