Got the coach running for the first time this season. Let idle for about 20 minutes. Coach never raised up. Checked the gauges, hadn't moved off of 20 lbs. Tried the air line drain valve in front of left rear tires, only got minimum air flow. Maybe 5-10 lbs. I can't hear any leaks anywhere while the engine is running. Besides the search here on the forum which I will be going through tonight, what/where should I be looking at/for?
Once again, thanks in advance,
Larry
Go back to the air compressor you will see an aluminum valve with a small hose going to it. That's the d2 air governor give it a small love tap or 2 with the engine running, it controls the air compressor. Use the search function at the top of the page and type in D2 air governor lots of posts on it.
Larry,
In order from simplest to more complicated;
Brake tank drains up front, Popet valve on wet tank, D2 governor, air drier,. With the engine running, I would start by placing my hand under the purge valve to see if I could feel air coming out. If the answer is no, then I would make sure the valves in front on the air brake tanks are not open, the safety blow off valve on the wet tank (Very unlikely) And then I would put your spare D2 Governor In. You do have a spare governor, right?
Don
Edit: Sorry about the punctuation, doing this on my phone in bright sunlight and so can barely read it.
Would start at the source and trace thru the D-2 regulator and the air drier,the source being the engine driven air compressor,see
if you can locate a line coming off the compressor and see if it's pumping air.
When I had a similar problem I discovered that the problem was the air dryer. If your air dryer hasn't been serviced in several years then that could be the problem. Suggest searching the forum for "air dryer."
Thanks everyone. I will be burning up the search function tonight, so if your forum useage is a little slow, I'm sorry. I have the manuals here at the house so I should be able to locate all the items mentioned. After work tomorrow I will begin the hunt. This learning curve sure is fun, isn't it.
Don, no sweat on the punctuation. I wasn't sure I had a D2 governor let alone a spare one :facepalm: :headwall:
Larry
D2 $15-20. Love tap means smack it lightly with hammer or cresent wrench
If that doesn't work take the plastic cone shaped cover off loosen 7/16 lock nut and screw in the pressure adjustment screw one or two turns CW and one or two turns CCW
Just had the same thing this past week on mine. I decided to go cheap first and changed the Governor...no dice so I started digging more and found the bottom of the air dryer venting out as fast as it was pumping air so wasn't gaining pressure. Changed out the dryer 300 dollars and bingo it fixed my problem. Good luck
Thanks everyone. I've spent the last 3 hrs searching past posts and it seems likely the dryer, but I will check the D2 governor first. I have no records from previous owners of dryer being worked on, so I fear for the worst. Even if it is the governor, I will at least check the dryer for the maintenance procedures from this forum. One of the fun things with owning an older coach is that you get to play with all the various systems and learn so much. Also being able to repair and keep running these wonderful machines is satisfying.
Since my printer has a better memory on paper than I do in between my ears, I have printed up nearly 100 pages of info derived from here. Posts, PDF downloads, pictures etc. All I can say is thank you all from all the posts who help add up the collective knowledge base. Couldn't have this coach without it.
I'll report my findings as I go.
Thanks again,
Larry
Been replacing our air dryer annually. From what I've read here and told by others, if air dryer fails it can send "gunk" throughout the air system with the potential for multiple component failures in the air system. May be pricey to replace but ultimately save money.
Yes I've read the horror stories also over the years. Didn't know where to start looking but have a better idea now. I have only put on 1000 +/- miles on the coach since I have bought it, so I hope that I don't have the dessicant problem. Never had anything come out of the drain valves when I checked them.
That work thing keeps getting in the way, but not for to much longer.
Larry
Same story for me last Sept...
dan
I changed my dryer last year with a Re manufactured unit I got at Napa. If your somewhat good with a wrench you can do it... I did mine at my storage spot.. and if it does go bad it is not "gunk" but powder that goes thru the system, you will see it if you drain the wet tank... ask me how I know that.. from what I've read the desiccant filter needs to be changed every 2 or 3 years under normal use and the whole assembly every 5 or 6ish years. Here's a pic of mine after I took it off the coach.....
Keith
It looks like mine that is still on the coach. Will look this afternoon.
Larry
If you have the same dryer, then you could try running the engine again and see if you feel air flowing out bottom of dryer. Will tell you if this is the source of your massive air loss. If YES, replace dryer with a new or reman, and yer good to go.
While I believe the problem is compressor /D2/ dryer, start at the D2 and make sure that it gets pressure from the compressor.
If it drove to the storage lot with air , it is likely that the dryer worked fine. Fire it up and feel the dump valve for air, if none, move back towards the engine , loosening the feed line, check for air, etc.
If your D2 is mounted directly on the compressor, take a picture, remove it, change it , try the system again. If the new one has no change. Remove it and blow softly through a rubber hose into the compressor ports. A little WD 40 or CRC will lube the valves.
If all of these parts seem to work, follow the air line from the dryer to the first tank.
Think were all telling ohso the same thing in different words.
In my case the dryer worked fine when it was put into heated storage for the winter-- but didn't work properly in the Spring. After checking the other portions of the system, the replacement dryer resolved the issue.
Here's where the D-2 governor is on a 97.
jor
I had a failing d2 controller on our coach when we bought it.
Pumped the brakes till all the air was gone on the dash gauge.
Started motor. Coach built pressure after that.
Replace d2 valve. Adjust to 110/130 psi for better brakes
Ok guys here is what I got. Started the coach, air gauges went from 0 to 30 and stopped. Never got above 30 with engine running for about an hour, both low and high rpm. Tried persuading the d2, which is mounted directly on the compressor behind the AC compressor. Nada. Foune the air dryer located lower left side of engine between the engine dipstick and side rail. It is a Haldex, couldn't see any numbers. Got underneath and located the plastic purge valve. I assume from Bob's picture that it is supposed to be open to the ground. Lots of dirt, grease and looks like it had something looking damp. Could be condensation from our weather, not sure.
In one of the posts I pulled up from Twig 4 years ago it says "Remove the screw on filter on the top and see if it airs up. If not, putt out the smaller filter down inside and see if it airs up. If not, uh oh. It's the dryer. If it does, it's the filter(s)." If I understand this, the filter canister will screw right off without removing the complete dryer? I'm sure this would take a strap wrench which I didn't have at the lot.
I'm thinking about making up one of the dryer bypass couplings and seeing if it will raise the pressure. When I crack the pit cock for the wet tank, by the DS rear wheel. I get a steady flow of air, probably the full 30#. Since the coach has settled down, I can't quite reach the two front tanks to check for pressure.
More researching tonight, that's for sure.
More comments appreciated.
Thanks,
Larry
Did you put your hand under the purge valve while it was running to see if you could feel the air coming out? It is pretty easy to tell, not a subtle thing at all if it won't build more than 30lbs.
Don
Yes, I took a rag and cleaned it up some. Didn't notice any air coming out at all. Not near the pressure from the wet tank valve.
Larry
The thinking that leads me to the following recommendation is this: Unless you know when the air dryer was last serviced/replaced then you can expect it to fail at an inconvenient time and place. Therefore, eliminate that possibility and proceed with additional troubleshooting if needed.
My recomnendation is to make sure the coach has zero air pressure and then carefully remove the iair dryer while carefully documenting where each line connects to the dryer. Then make a bypass out of pipe to connect the two main lines together and cap any control lines. This should allow full air pressure to move the coach and/or do additional troubleshooting. Use the information found on the dryer to order a rebuilt replacement.
Figuring out air system puzzles is always fun. So what do you know so far?
With engine running, your dash air pressure gauges go to 30 psi and then stop going up. This tells us your air compressor is compressing air, which is a good thing, cuz new compressors are expensive.
Air goes from the compressor, to the dryer, to the wet tank, to the other two (front and rear) air tanks. If you show 30 psi on your dash gauges, it is a pretty safe bet that you have 30 psi in your wet tank, and 30 psi in your front and rear tanks. If the drain valves were open on either the front or rear tank, I think you would be able to hear it.
Question: What do your dash air gauges do when you shut off the engine? Do they hold 30 psi, or do they bleed off. If they bleed off, is it a fast or a gradual drop in pressure?
But the BIG question is, why does pressure stop building at 30 psi? When the coach was running, did the air dryer ever purge (make the normal sound it does when the compressor cuts out)? Or did the pressure stop climbing, but you never heard the dryer pop off?
You couldn't feel air coming out of the bottom of the dryer, so the purge valve is probably closing like it should. Like Don says, you would know if it was stuck open. Don't worry about finding dirt, grease and oil around the dryer purge opening - this is completely normal. A little oil gets mixed with the compressed air that comes out of the compressor. One of the functions of the air dryer is to remove this compressor oil from the air, and expel it out the purge valve.
If it was me (I am a lazy sot) before I messed with removing and replacing the dryer, I would first install a fresh D2 governor. It's a LOT cheaper than replacing the dryer, and a LOT less work. If it solves the problem, you're golden. If not, you have at least eliminated one possible factor. Then you can move on to the harder stuff.
But that's just me.
That is the next step. Get a new governor. Stopped at OReilley's. The youngster their couldn't find his way out of a paper sack let alone anything on the computer. I left after 30 minutes. I had called the same store yesterday, the guy had the part, price and could get it for me in the morning. I told him to wait till I check it out. Mistake. Will call tomorrow and get it ordered.
When I shut off the engines, the gauges held. I restarted the engine before I left and they were at 30 pounds. Probably 15 minutes with the engine shut off. Coulldn't hear anything leaking, but who knows, I have a lot of hearing loss. I have heard the pop off valve before, but not since starting this season.
Thanks for the help. I won't be able to get back till Friday night, so we will see.
Larry
Still thinking about your reported symptoms. What malfunction would account for this combination:
1. The air compressor is compressing.
2. Compressor fills the system tanks to 30 psi but doesn't increase the pressure any higher.
3. You haven't
heard the compressor unload (dryer pop off).
4. You shut engine off and the dash air pressure gauges hold at 30 psi.
So far, the only hypothesis I come up with is a
leak somewhere between the air compressor and the wet tank. The leak would allow air pressure to build to 30 psi and then would be large enough that it would exhaust air at the same rate that the compressor supplies air. In this state of pressure equilibrium, the compressor would never unload but would keep pumping, yet the dash air pressure gauges would never rise above 30 psi. When the compressor is shut down, the inlet check valve at the wet tank would hold the pressure in the system at 30 psi.
So what components are between the compressor and the wet tank? There is a big air hose from compressor to air dryer, the dryer assembly, and the air line from dryer to wet tank. The D2 is also connected to the compressor, the dryer and the wet tank, so D2 plus any air hoses attached to it would also be suspect.
If anyone else can postulate a more logical failure mode that fits the symptoms listed above, please post it here!
In the meantime, I would
still replace the D2 as the next step, but while working also carefully inspect the air hoses for abraded spots.
Time for a lot of soapy water?
Replace the D-2 by all means,check the plugged ports on the D-2 and see if you can put a gauge on the D-2 (it's 1/8 npt).Then
you can verify the 30psi,if the air compressor is only reaching 30 because of a leak that's a hell of a leak.I know we don't have
many actual air compressor problems but that does'nt mean they don't fail.
I don't know anything about air compressors, or what could go wrong with one. Any Forum "air compressor experts" feel free to chime in.
Could a engine driven compressor suffer some malfunction such that it would compress system to 30 psi and then "stall out" at that point?
The unloader valves can get stuck and cause the same symptoms. I have had it happen and freed them up with Corrosion X sprayed into the port after removing the D-2 governor.
If you connect the 2 large lines and cap off the 1/4 inch line coming from the governor, you don't even need the air dryer. The coach will cut in and cut out as usual. Drive it until you decide to replace it.
Might do that as a last resort but would not want to chance moisture in the system,a few drops goes a long way.
Completely agree. I bypassed mine to get the coach home while awaiting the delivery of the new air dryer, but I wouldn't regularly drive it without an operational dryer.
Back in the day, trucks and buses did not have air dryers, and the driver used to have to drain his tanks manually every day to remove water from the bottom of his tanks.
Thankfully those days are just memories for most of us!
Picked up my new D2 tonight. Will try to work on it tomorrow after work, weather permitting. Told one of the mechanics at work what it was doing. First words out of his mouth was, "replace the governor". I don't think he was talking politics.
Craneman, I don't have any Corrosion X, any other brand worth mentioning? Is it like PB Blaster, WD 40 or something entirely different?
Thanks for all the advice so far, I do appreciate it.
Larry
Larry, PB blaster should work. The unloader valves are spring operated and can get hung up either way. Creating high pressure or low pressure.
Thanks Chuck, got PB at the coach. gotta get to be d now, 4 o'clock comes early.
Larry
Update: Replaced the D2 governor, didn't fix the problem. Coach stops at 30#.
I identified the drier as a Haldex Pur Air Plus Dryer
As per a comment on "No Air Pressure" from 4 years ago from Twig when Amos Harrison had this same problem, I tried removing the desiccant filter, still no go. Removed the coalescing filter, nothing. Put back together and checked the purge valve. It was stuck open and with the coach at 1300 rpm idle, I couldn't hold the pressure back with my palm. I have hope that this is the problem. I'll be checking on new purge repair kit, coalescing filter kit & desiccant kit. Since I don't have any idea when filters were last changed, ain't no time like the present.
In the topic which I I commented on, Amos stated that he had found "the broken parts inside the drier" but he didn't elaborate any further. When I was looking down inside where the coalescing filter goes, there was a piece laying there. I can move it back up into position that somewhat resembles the Turbo Saver Valve shown in the cutaway view on the dryer. It appears that the valve part might have broken off. The cutaway also shows a valve assembly coming through the purge orifice but I see no evidence of it being there, Anyone have any ideas what this is and is it likely broken?
My first plan of action is to build a set of bypass connectors and bypass the dryer completely to see if it will build pressure. If so, I'm hoping someone can tell me the likely hood that the drier is bad or just the purge valve. I appreciate any comment or advice from the ones here wiser than me on this system.
Larry
Larry,
OK, back to basic first question-- how long since the air dryer has been replaced/completely (yes completely, not just filter replacement) serviced??
Brett, I have no records from the previous owners showing it was done. However the desiccant filter was dirty on the outside but you could still read the factory writing with little difficulty. It also removed reasonably easy with a strap wrench to break it loose and then the rest by hand. The drier on the other hand is filthy and caked in dirt/grease from the road it appears. The purge valve is dirty, but wiped clean enough to read with a rag. It may have been replaced along with the heater element. It looked reasonably clean considering its location in the engine bay.
Larry
Should'nt have much oil or grease if everything is clean and working good,if too much oil is coming from the engine air compressor
then that is a concern.
If the air was working ok before storage I don't think your missing a part ,how would it have worked before?Think you either need to
get every kit for the drier and rebuild it yourself or get the reman,When I did mine I had it in a vise and cleaned and blew out and
had to sand a ridge from a passage,at some point you will have to get a reman anyway now might be the time.
"too much" is difficult to quantify. Everything I have seen concerning air compressor performance standards leads me to believe that SOME oil is OK, but TOO MUCH is not OK. Bendix Advanced Trouble Shooting Guide seems to think oil being purged from dryer is
not a cause for concern. See Symptom #3 (Page 5):
https://www.bendix.com/media/documents/products_1/compressorsgovernors_1/troubleshootingguide.pdf
OTOH, if there is oil in your wet tank (or worse, in your front and rear tanks) then
that requires further investigation (see Bendix Guide above)
If the system will build proper air pressure after you bypass the dryer then replace the dryer with a completely remanufactured unit. They are not that expensive and it just makes to start with a fresh unit.
It looks to me like you just need to replace the drier. You can make the bypass kit but from everything you have said the drier needs replaced.
There is oil and water on the inside where the coalescing filter is. Not a huge amount, but some. I'm not terribly worried about the amount from the compressor, at this point. That can always change as we know. The main dirt/grease is on the outside of the dryer where it is exposed to the elements of highway travel.
When I put it into storage in November, we had just driven it 600-700 miles within the preceding couple of weeks. Everything worked fine. I'm thinking of the purge valve to see if it is the culprit. With no prior knowledge of maintenance from previous owner(s) I will be changing the filters anyway. I've read to many stories on the result in contaminating the air system.
Keep em coming,
Thanks,
Larry
Ron, was typing when you replied. Does a reman dryer come with the filters already or is this a separate line item?
Larry
It is complete ready to install keep your old one until the new one is installed to make sure you have all the fittings then turn in the core to get the core charge back.
Thanks Ron, will be checking on it this week. I may still bypass the old one so that I can raise it up to work on it. I barely fit under the back and there ain't no way under the front. After changing the starter last year low to the ground, if it can be raised, up she goes. And yes, I have a set of safety stands ready to stick in place.
Thanks,
Larry
Larry,
If you can't get the unloaders freed up it's an easy job to replace them if you have a newer Bendix Tu-Flo 550 not a 501 like mine. You can access the valves from a cover plate on top without having to take the head off. It's a real PITA on a DD6v92 with a TU-FLO 501.
When I serviced the drier I found out the compressor would not stop building air after I bypassed it. The unloader valves were frozen and rusted shut from prior lack of service and I couldn't get them loose. I didn't notice it before because the drier was still purging. In other words, the compressor was never unloading! A new set of unloader valves did the trick and now I can hear a slight difference in engine rpms (higher) when the compressor unloads.
https://www.anythingtruck.com/product/060-107515N.html
Jerry
Some of us carry a double male quick connect air fitting that allows us to pressurize the wet tank (and the rest of the air system) through the tire filler hose, using a portable air compressor. You only need about 90-100 psi in the tanks to fully inflate the air bags to max lift.
The main objection to this procedure is that you are using "wet" air to pressurize the system. But if you are going to bypass the dryer, it is the same difference. Would save you some work, and having to run the big engine.
Thanks Jerry, one more thing to keep in mind after I bypass and it doesn't stop. By servicing your dryer, what did you have to replace?
Larry
Chuck, I wish I could but the coach is in a storage yard with the closest electricity 1/2 mile away. I thought of an air bubble to do that, but would probably tak a dozen trips to get it up and the coach is 20 miles away :o That is one of the reasons this is taking so long, as well as that work thing.
Larry
Start the generator and use the coach 110V outlet to power the compressor. Genny probably needs exercise anyway.
I still have the Bendix AD-4 outdated drier but was able to find a new cartridge and a rebuild kit that has the seals, purge valve, etc. at the local big truck parts store here for about $150. Didn't need any new fittings or bracket with the old case. The replacement models are much better and easier to service. The kit comes with instructions. The hardest part was getting it out!
Jerry
Yes, a FACTORY (as in the factory that made it, not someone elses reman) comes with all new valves, heater and filters.
THAT is the way to go, particularly if you don't know how old the air dryer is or what shape of everything inside.
Another option if you have an obsolete dryer (Bendix AD-4 comes to mind) is to contact the factory that made your dryer and ask what supercessions are exact replacements (connect exactly the same as the old one). Been there, done that.
Chuck, I would like to start the genny but the fuel lines started sucking air so the genny quit running. Got a small piece of new line and fed from fuel can, ran like a top. I had planned on replacing the fuel lines all around this past winter, but with work and the worst winter we've had in years, didn't happen.Once the air problem is resolved, it's back on the fuel lines.
Jerry, I have the Haldex dryer. I have checked with our parts manager at work and he has located a reman haldex for about $200 + core. The best I could find online was $250 + core. I have made up a bypass fitting and will try to install tomorrow after work. Once there, I will remove the core, get the new one and put back in.
Larry
Be sure that you have the exact replacement for your air dryer. They come in different varieties, and so it's important to get the exact match.
David, the manufacturers spec sheet calls for DA3100X. That is what was quoted. Are you saying there are different versions of this model number?
The spec sheet is probably--emphasis on probably--correct. I just don't really trust spec sheets and so I would carefully compare the old and the remanufactured units to be certain.
Larry, as long as the model # is the same make sure all your fittings fit your golden. You can even change manufactures they all do the same thing. Just a matter of connections. I like the Haldex dryers better than Bendix units.
Larry,
That is the correct number. Make sure you remove all the fittings off the old one before you return it for core.
Mike
Thanks to all of you. I have looked at the website for as much info as I can as well as what was supplied with the coach manuals. Actually impressed with what they show in there.
OK, here is where I'm at. Went to the coach to try to bypass the hoses. Brought a set of connectors in both 1/2" and 5/8" brass air hose fittings. Wasn't even close to big enough. It looks like it is about a 1" fitting that would be needed.
Since I couldn't bypass it, I did the next best thing. I removed it and brought it home. I will take it to work tomorrow and get the new one on the way. Don't know if I will have it tomorrow or the next day. I still have the 2 large fittings to remove from the dryer, but I can get that done at the shop. It took me less than 1/2 hr to remove. Hopefully the reinstall won't be much longer.
Thanks again for the support and advice, I will keep you posted.
Larry
Larry,
Those fittings are probably 37º JIC fittings often used in hydraulics systems, not like the DOT air brake fittings used by FOT with the HTFL Polyamide fuel line. If you remove the two large fittings form the dryer, they are probably ½ male pipe thread on the air dryer side and JIC (I forget the size designation) on the other. You can make a bypass with those two fittings using an ordinary ½ female pipe thread coupler. You will probably still have to plug or cap a small ¼" air line so that the cut off functions (at least I did). You can also take those to JIC fittings from the dryer and take them to a hydraulics shop to match them up so you can have a bypass kit already made up for future issues, which probably won't happen if you have the kit with you. ::)
Don
While back I did a thread about bypassing the dryer. Link to one of the posts below - shows what parts I needed for the dryer on our coach.
Air Dryer Bypass Demo (http://www.foreforums.com/index.php?topic=22007.msg165793#msg165793)
I also carry a set of JIC plugs of various sizes in my tool kit. They are handy for plugging air and/or hydraulic hoses. See post:
Emergency bypass kit for Haldex air dryer (http://www.foreforums.com/index.php?topic=25039.msg197529#msg197529)
Chuck, I printed out that write up you did. It helped me tremendously. Thanks.
Don, I will go ahead and make up a bypass just to have for an emergency for me or someone else. I still have to remove the 2 large fittings at the shop tomorrow, but I will check on the 1/2" pipe thread, we have lots of 1/2" pipe, The only thing that surprised me was the small fittings. On 1 side was a Tee fitting with one hose going up towards the front somewhere (didn't trace) the other going around the air dryer to another large fitting which had the air supply hose, and a small plastic line with a compression fitting (heading up front also). Is this large device some sort of solenoid or what?
If I knew how to post pictures from my phone, but alas I don't have one of my 12 year old grand kids here to show me the way.
I wasn't sure how much of the fittings needed to come off, so I hope to find out tomorrow.
Larry
You might be looking at the isolation valve. See thread linked below:
Pure Air Plus Air Dryer (http://www.foreforums.com/index.php?topic=34804.msg322201#msg322201)
The isolation valve does NOT come with the reman,found one on Ebay.
Thanks Chuck & John. I was to tired last night to remember what it was called. I remember from your link reading about it.
Larry
Yes, I have one of those and occasionally use it. After using it I haven't noticed any more water than usual when draining the tanks. Everyone drains the tanks after a days driving, right!!! The main purpose of the dryer is too prevent ice in the brake lines during freezing weather. Most of us don't drive in freezing weather. Anyway after a little bit of driving that air will be exhausted and replaced by air from the dryer. A few years ago I moved the drain valves on the front tanks to an easy to reach spot, so I didn't have to crawl under the coach to do that. Similar to the drain on the wet tank.
I don't wsnt to add to the confusion but this discussion jogged my memory and when my dryer failed about 3 years ago I replaced it with a unit containing the built-in check valve. I believe the unit I used was the Haldex DA33200X. This simplified the plumbing and eliminated the need to purchase an replacement valve.
Jerry, after not being able to get to the tanks because it sets so low, you just gave me another project to add to the list. Thanks, I kinda enjoy these projects.
David, what did the check valve change in the plumbing? When I got with my parts manager today, the vendor with the DA33100X was there. He recomended that I get the new and improved model to replace the one I had. We had some of these on the shelf. After looking at them, the plumbing was totally different. I opted to get the direct replacement. It comes tomorrow.
Larry
I don"t have pictures or an air line diagram handy, but I think someone posted a diagram earlier in this thread. My old dryer had two lines running from the dryer to the check valve mounted very near (essentially mounted to) the dryer. The new dryer with the internal check valve doesn't need that external valve and so I was able to "clean up" the installation by eliminating those lines and the valve and (as I recall) capping one control line running to the external valve. For me (at least) a simpler installation with fewer lines and connections is a good thing, especially since the external valve design seemed rather like a "band aid" to solve an issue that is better handled with the internal check valve design.
Thanks Chuck. Yep I got the external check valve, but I already have this one coming. It's worked the last 22 years, probably will outlast me.
Larry
Just be sure to rebuild the air dryer (or even better replace with a factory remanufactured unit) about every 5 years.
Does anyone have a Bendix or other manufacturer chart recommending air dryer replacement at this interval? I have charts where Bendix recommends the "Dryer Cartridge" replacement at 2-3 year intervals based on duty load. Seems a 5 year complete dryer replacement when the cartridge replacement is almost 3 years is some what conflicting.
Swap the spin on style annually .
I found it cost/time effective to change to a modern spin on style Dryer. Took a little more on install but so far totally worth it. Parts/filters are readily available so down time is nil.
Mike,
Do you have a part number for your new dryer? And was the plumbing compatible with your old one? (Its in my garage!!)
jk
100$ eBay . Had to drill mounting holes, and run the hoses a little different. NAPA stocks the cartridge . The NAPA guy acts like "they all have them ".
955205; The price came down . ;AIR DRYER ASSEMBLY - REPLACES MERITOR WABCO SYSTEM SAVER 1200 SERIES R955205... (https://www.ebay.com/itm/AIR-DRYER-ASSEMBLY-REPLACES-MERITOR-WABCO-SYSTEM-SAVER-1200-SERIES-R955205-/252085515947?hash=item3ab177b6ab)
I took it to NAPA and matched up the cartridge before I mounted it as the Ebay cartridge had no part #s on it . I also swapped it for a known good new filter after about a month . I had to mount it to remove the cartridge :) tight.
The replacement cartridge cost about 60$
I show an install date of Sept 2017
While I'm showing perversions of my unit, I may as well show the Racor replacement . I called Wix asking about the GM Duramax filter GPH rating and was told that any of the 3/4 16 mounted filter will flow enough fuel for 450HP . MY OE was rated 65 GPH( 1 in mounting stub) and the GM is about the same . The shown filter has the water drain option @ 10 Micron +-.
As far as service interval, my recommendation is every 3 years. Yes, if you drive 70,000 miles a year, maybe every 2 years. And if you live in the desert SW maybe every 5 years.
FACTORY (by the factory that made it, not a "made to replace" reman every other dryer service. If you don't know dryer service history, start with the reman. It will have new valves, heater, etc, not just filters.
Every other service with filters only.
Mike,
Thanks. Your install looks good.
jk
Just got my new Haldex remanufactured air dryer at work today. It sure is pretty. Even comes with a new 12 v heating element. I guess I will remove the old one and keep it for a spare. I accidentally removed some of the wrong fittings from the old one so that some of the different valves were exposed. The person delivering the new one said "Keep em. Were just going to put them in the remanufacture bin and send it back to be rebuilt. They will use all new parts. "
Hope to get the time this weekend to reinstall and see if the air gets me back to the 110# range.
Larry
Update: couldn't get to the coach all weekend long. To many things to do. Went after work, had the air dryer reinstalled (except for the heater) in about 45 minutes. Fired up the coach, went past 30# yeah!!!!!!!!!!! Struggled to 70# and seemed to falter. OH OH. Even on high idle only 70#. Found the leak. (Don't ask me how I know where the wet tank valve is). Closed valve air went to 125# and never faltered. Let the coach idle for about 15 minutes to build the batteries. Stayed at 125#. Life is good.
Larry
Love a happy ending!
Congratulations Larry! So glad you got the problem resolved--and had a great "learning experience" about the systems on your coach. Even though it can sometimes be frustrating it's fun to learn more about these beautiful machines!
With that valve open it was making the drier work harder.
Did you ever replace the isolation valve?
Thanks all, I feel much more confindent in my knowledge about the air system. Loved learning about it. Was able to diagnose a similar problem on the crane at work because of what I had learned.
John, I didn't replace the isolation valve. The old one seems to work well. Not really sure what it is for.
Larry
finally happened Got coach from storage everything works except rear air gage. turn key goes to to 30 then to 0
Everthing on coach works the way it is supposed to, even emptied the air /water valve (n0 water) What is causing gager noot to register?
Larry,
It was installed as a fuel saving feature. The application depended on the air compressor that was used along with several other engine options.
Mike
Probably a bad sending unit on the tank.
Dan,
Don't know for sure, but guessing with your model year coach you probably have electric air pressure gauges, as opposed to the direct reading mechanical dials on older models (like mine).
If I am correct, just like any electric gauge, check the ground wire and "signal" wire coming from the pressure sensor. Look for loose connections, damaged insulation on wire, etc.
Someone else will have to tell you where the actual pressure senders are located.
On an '02 you may have the magic "blue/grey" (some are blue some are grey) interface box that converts the air pressure to an electrical reading. This info is then relayed to the gage making it read. This box is located under the flip up dash. If this is the type system you have you may have a bad ground or the box may be starting to fail. Once the converter/magic box fails some have just changed the gages out to direct read.
Mike
Chuck beat me to the post button but hopefully this will be of some help.
Thanks Mike. Any time I can save fuel you can believe I will.
Appears the sender may be bad. I am so dumb. How do I raise coach so I can crawl under?? Tks for ur help
OK, first question is do you have safety stands? If not, the only safe way is to drive wheels up on boards (that support whole footprint of the tires). Basically, you need clearance so that if anything happens to the air suspension you still have safe room to crawl around.
If you have safety stands, you can use the air leveling to raise the coach (or just ride height at an axle) and install safety stands before crawling under.
And, may be nothing more than a bad (loose or corroded) connection.
Tks Brett will do.
Dan,
I'm not for sure but on your coach I think your pressure transmitters are in the dash. Above and between brake pedal and steering column.
Mike