dandick66

1 hour ago, jacwjames said:

All my PPV's started to land and I replaced.  I took each apart and they all  had corrosion.  The initial ones were all installed upside down.  The top has a hole it and it should be pointed down, which I assume was to release condensation. 

Jim, 

That’s interesting.  The valve in the picture has a small piece of red plastic in the top.  The new valve was open at the top.  I emailed WABCO and they couldn’t tell me if the new valve was supposed to have the plastic piece or not.  They did however, tell me it didn’t matter which way the valve was oriented.  I can see that if the valve was mounted downwards, the water could not accumulate in the bottom.  I think I’m going to reorient the one I just installed.  
Back under the coach tomorrow.  I think I’m going to put a cooler under there…

I decided to not crawl under the coach too much today.  I did pull the front tank PPV and put a plug in the tank.  I let the pressure build up and I’ll see how it is in the morning.              
                                                 
I did notice the coach squatting in the passenger rear.  I sprayed around the Valid manifold, but didn’t see any signs of leaking.  I’ll investigate it more later this week.

I did do some failure analysis on the PCCV.  I can see why the check valve part didn’t work.  The spring actually broke in 2 places and there’s a lot of rust.  I guess that proves that you should drain your tanks…

2 minutes ago, 96 EVO said:

I'm sure your getting sick and tired of crawling around under your coach by now 😬!

You got that right!  I can’t wait to get this fixed…

1 hour ago, 96 EVO said:

If it's easier, you could just temporarily replace the PPV at your front tank with a plug, and leave your elec compressor off, and see if your overnight system air loss slows down.

Yes, that might be easier.  I’ll let you know how it goes. 

Ok. I’ll try that a little later today…

1 minute ago, 96 EVO said:

Should work.

1 hour ago, 96 EVO said:

Believe they will equalize.

No guarantee this is where you are losing air, but if your compressor is easy to get to, it's an easy job.

Leave your compressor powered up, and if it starts running frequently, like every few hours, it may be worth doing. 

Ok. The compressor isn’t the easiest thing to get to, but I can access it. I see a .25 inch line running from the front tank to the Valid compressor tank. Out of the compressor, there’s a “T” to the Valid tank and a 3/8 line that runs to the front, rear and tag manifolds.  Could I just plug the .25 and 3/8 lines temporarily and bypass/eliminate the compressor?

4 minutes ago, 96 EVO said:

Ok, you may be losing system air right through that compressor like I was.

Did you see the long thread where Frank removed the head off his compressor and cleaned the reed valve and '0' ring below it?

Worked wonders for me, reducing overnight system air loss!

I haven’t seen that thread, but I’ll search for it. 
       
Looking at my air system diagram, the supply to that compressor is only connected to the front tank. Would it cause the rear tank to drop, too?

1 minute ago, 96 EVO said:

Does the compressor run often?

Do you have it disabled, like many of us do when parked long term?

Yes, I have the compressor disabled.  I mounted a switch near the dash and test it periodically.  

23 minutes ago, 96 EVO said:

Dan, does your coach have Valid air leveling?

Yes, Vaild leveling system 
VTL01K049

UPDATE 22 MAY

I installed the new replacement pressure control check valve on Friday 19 May - the first one I received was defective.  I started the engine and the pressure built up to 127 PSI.  The rear tank dropped about 10 PSI, thereby indicating the valve is functioning properly.  I drained the wet tank and both the front and rear tanks held pressure.  I drained the front tank and the rear tank held pressure.  Then I drained the rear tank and the front tank held pressure.  I did restart the engine and let pressures build up between each scenario.  Here is the timeline and pressure readings I recorded.                              
19 May 1430 Front 126/Rear 118 (Following governor cutoff and regeneration).     
19 May 1910 Front 111/Rear 104.  (Approximately 5 hours, 15 PSI drop front, 14 PSI rear)
20 May 0630 Front 91/Rear 91. (Approximately 11 hours, 20 PSI drop front, 13 PSI rear)  
20 May 1900 Front 79/Rear 79.  (Approximately 12 hours 12 PSI drop front, 12 PSI rear)
21 May 0700 Front 67/Rear 67.  (12 hours, 12 PSI drop front, 12 PSI rear)
21 May 1830 Front 59/Rear 59. (Approximately 12 hours, 8 PSI drop front, 8 PSI rear)
22 May 0700 Front 49/Rear 49.  (Approximately 12 hours, 10 PSI front, 10 PSI rear)

I’m not exactly sure what my data indicates.  It appears that the front tank dropped pressure a little faster than the rear until they equalized and then they dropped pressure equally.  It leaks about 1 PSI/hour.  I don’t know the accuracy of the transducer and gauges, but I’m assuming it’s +/- 2 percent.  I have not installed the new spring brake hose yet, but I don’t think that affects any readings since it has no pressure when the parking brakes are engaged.        

 

17 hours ago, Tom Cherry said:

I would tell you that the Medallion system (I have it) is notorious for giving a LOW Battery warning.  Me and several others have seen this and we KNOW that our batteries are in great shape.  The BEST way (OK...there are many) but a simple one.  In the heat of the summer, stop and shut down the engine.  Then go back and unhook your toad (or wait the equivalent time.  Then, jump in, with the Front HVAC on and start the MH.  If you have that OMG.....pause, then it cranks....probably TIME to think about a chassis battery.  The engine when hot (90 dF day or so) will quickly heat up and expand.  That means the compression is higher.  With a NEW set (you need the 950 NOT the IDIOTIC 750's that Monaco put on the Camelot....the Dynasty got the better batteries) of 950's I STILL get the idiotic light.  BUT, I get 6 or 7 years out of the best Interstate Starting batteries.

As to the Software ID.  Call Medallion.  They will discuss that.  I THINK or maybe not....that MINE does it.  It has absolutely ZILCH or anything to do with the ECM or the ENGINE....strictly, I think, the Software in the Medallion brain that runs the system.

My 2012 Diplomat is Rev 1.2.  Like Ivylog said - ignore it…

Tom, Have you ever seen “HIGH BATTERY “ displayed on the Medallion?  Mine did it a couple of times and the engine will crank, but not start.  Cycling the ignition key several times usually cleared it.  The last time it did it I connected the Navistar Diagnostic software and discovered that it was low power to ECM.  I found a relay that was sticking and not allowing 12 volts to the ECM.  Apparently, Medallion takes the J1939 data and converts it to whatever they want.  They could have the message say “Good Morning “ if they wanted to.  I replaced the relay and all has been good since.

10 hours ago, Ray Davis said:

Freeways where the semis can't drive in the left lane you better stay out of the center lane, some semis will practically give you a push.   Of course, sometimes you are sort of stuck in the lane.  I prefer the middle lane when I have one but I don't have a hard & fast rule about the lanes because each situation is different and not all exits are on the right,  some are on the left, and those can throw you a curve if you don't know.  Sometimes at freeway speeds the signs are not far enough in advance to maneuver to the correct lane, & then the stress level really goes up.    Oh boy, that's when you need your navigator to be wide awake.   Miss your turn & you may end up in Timbuktu.

Not sure if everyone is aware of sign placement on interstates.  I’ve had exits “sneak up on me”, but I try to be a little more attentive when I know I’ll be exiting soon. 
 

I stopped at the one in Florence (in my pickup) just to see what all the hype was about l. I figured out why they have so many pumps - no one uses the parking lot.  They just leave their cars at the pump and go shopping and dining.  I don’t know if I’d try to go there with the coach.  It’s a mad house.

I just found out they’re building one here in Virginia,  or too far from me.  It will be on I 64 between Richmond and Williamsburg.  

25 minutes ago, Frank McElroy said:

I would be very careful in changing brake line air hose diameter from the OEM original design.  The system was designed to meet DOT standards for certain air flow rate for the speed in which the brake cylinders respond in a balanced way for rapid setting and rapid brake release and pulsed operation of the ABS system.  Changing from a 1/2" to a 3/8" hose will have a significant effect on the system due to the much lower air volume flow rates.

I found another place that has the 1/2 inch hose.  I am going there in Wednesday to get the hoses made.  I didn’t think about the ABS aspect, but was going to use the 1/2 inch hose for commonality.  Thanks for pointing that out.

2 hours ago, Bill R said:

@dandick66 Dan I am interested in what you find out.  To me it seems you may have an issue in the Air Dryer system if you are having oil get through.  Let us know what your find out.

1 hour ago, Frank McElroy said:

Dan, actually both tanks will drop 3-5 psi when the air system reaches the cutout pressure and the air dryer expels condensed water and oil.  Although initially the air comes from the rear tank, the two dry air tanks will equalize air pressure through the dual check (shuttle) valve.  So, on your gauges you should see both tanks drop slightly.

40 minutes ago, 96 EVO said:

Both of my gauges have dropped together during desiccant filter regeneration.

I've never worried about it, but wasn't sure whether it was right or not!

I reinstalled the old valve today.  The air dryer is regenerating now as it’s supposed to.  Unfortunately, the check valve portion of it is bad so when I drain the wet tank, the rear tank drains, too.  The regeneration process is removing the oil from the dryer, because I’m not getting any oil when I drain the tank with the old valve.  
 

I’ve ordered a new valve, so I’ll get it installed as soon as it are.  It’s too bad I can’t take the working portion of both valves and have one good valve.  There was some success today.  I found one of the hoses from the inversion valve to the spring brake chamber was leaking.  That explains why I was losing some pressure while driving.  That was another learning experience.  I went to the local NAPA to get a new hose made, only to find out they can’t make the hoses.  Apparently, you have to be DOT certified to make the hoses.  I went to a truck shop and he only had 3/8 hose and male fittings.  Monaco (at least my Diplomat) uses 1/2 inch hose with female swivels.  They installed nipples on both the chamber and inversion valve- I have no idea why Monaco did it this way.  
 

I think I’m beginning to see light at the end of this tunnel.  I just hope it’s not a train coming towards me…

7 hours ago, 96 EVO said:

Well hopefully your tanks are behind your front axle like mine. Little more room up there to work!

The wet/front tank is behind the front axle and is easy to work on.  The rear tank, where the valve is, is above the differential and it’s a challenge to get to.

2 hours ago, 96 EVO said:

Yeah, that's the one!

Definately, re-install the old valve and see what happens. You may have gotten a faulty valve.

Secondary tank! Look at the picture of the PCCV in the link I posted.

I’ll put the old valve back in tomorrow.  I assumed that it was working as it’s supposed to since it was preventing the air from flowing back through the wet tank to the front tank.  

3 hours ago, 96 EVO said:

This was the valve you replaced on the secondary tank?....

https://tectran.com/content/TB_AD21.pdf

It’s very similar.  Here is the one I used.  It’s the same model as the one I took out.  I placed it on the rear tank, which I think is called the primary tank.  
https://www.haldex.com/en/na/air-dryerair-line/air-dryers/competitive-newremanufactured/wabco-ss1200-repair-kits/s4341003100/

12 hours ago, Bill R said:

Dan - when my dryer purges it only does it for about 1-2 seconds and the pressure only drops about 3 psi.  I had talked to a Wabco tech about this a year ago and he said that is fine.  Perhaps your purge dropped the pressure more before because the charging valve was bad. 

Bill, I don’t think it’s working at all.  I am getting oil in my wet tank now.  From what I’ve read, that’s the regeneration valve not working.  The weird thing is that it was regenerating before I replaced the valves.  Before I replaced the valves, both tanks would drop approximately 10 PSI after the compressor cut out.  I found out that only the rear tank should have dropped the 10 PSI.  That was a result of the failed pressure protection valve.  The Haldex manual indicates the problem could be the governor or regeneration valve.  I have a spare governor and I think I’ll change it out tomorrow.  The regeneration valve kit is pricey- around $250.  

Update

I got the new shuttle valve and pressure control valve installed yesterday.  I used Loctite Blue on the threads and it call for 24 hours to fully cure.  I waited until this afternoon to start testing.

I’m happy to report that the new valves are working as they’re supposed to.  When I open the wet tank drain, only the wet tank pressure drops.  When I open the front tank drain, the front tank pressure drops and the wet tank and rear tank pressures hold.  When I open the rear tank drain, the wet tank and rear tank pressures drop and the fron tank pressure holds.                 
                                        
Now the bad news.  For some reason the air dryer is not regenerating.  The pressure is supplied to build to approximately 125 PSI, then drop about 10 PSI for the regeneration cycle.  I am not getting the pressure drop.  The WABCO manual says the problem could be the governor or the regeneration valve.  It’s weird that the regeneration process worked fine until I replaced the shuttle valve and the pressure control valve.  
 

More troubleshooting tomorrow…

Dan

47 minutes ago, RoadTripper2084 said:

I'm enjoying following along as you determine the root cause of your leak deductively. Do you have a table showing what your expected/correct outcomes are for each of these test scenarios?

 

I will do a postmortem once everything is fixed.

28 minutes ago, 96 EVO said:

Losing 10psi from your rear & wet tank immediately after the compressor unloads is the dryer regeneration valve opening to dry out the desiccant filter.

Before I started all of this testing, whenever the governor cut out my front and rear pressures would both drop 10 PSI.  I thought that was normal.  Now, with the shuttle valve removed and line plugged only the rear tank drops 10 PSI.  I’m learning more every time I crawl under there…

New Testing today 09 May

I removed the shuttle valve/2 way check valve and plugged the output from the dry tank (this was 1 of the inputs to the shuttle valve).  I plugged the silver 1/2 inch hose that was the other input to the shuttle valve (from rear tank).  I left the green 1/2 inch hose unattached- I think it goes to the spring brake relay).

 I started the coach and let it build up pressure until the governor cut out.  I noticed that  the 10 PSI drop that normally occurs after governor cut out only affected the rear tank - the front tank held at 125 PSI.  Next, I opened the wet tank drain.  The rear tank pressure dropped, but the front held.  I confirmed the rear tank drained by opening the valve at the rear and there was no pressure.  I cracked the front tank dry drain to confirm it was still full/holding.

I started the coach again and let the pressure build up.  I opened the rear drain and the rear pressure dropped and the front pressure held.  After the rear tank emptied, I cracked open the wet drain and there was no pressure.  I cracked the front tank dry side drain valve to confirm it was still full/holding.

I started  the coach again and let the pressure build up.  I opened the front tank dry side drain and both front and rear tanks dropped pressure.  I opened the wet tank drain and there was no pressure.

I believe this testing confirms that the wet/dry internal check valve is working properly.  I will install the new shuttle valve and new charging check valve when they arrive.  I’ll post the results.  
 

Dan

3 hours ago, Frank McElroy said:

Well, if you drained the wet tank with the quick connect fitting and that line actually goes to the wet air tank then the dash gauge is reading pressure from the wrong air tank.  First time I've seen an air tank gauge connected to a wet tank.

Is the top in the photo for filling the tank?  On my coach the fill fitting has a valve behind it for draining the wet tank.  Under that is the front tank drain.  The rear tank drain is back next to the trailer hitch.  
My valves are supposed to get here Thursday.  In the meantime, I might put a plug in the front tank where the shuttle valve was and then plug the line coming from the rear tank.  I think then I can test the set/dry check valve.  

2 hours ago, Frank McElroy said:

Dan, let's not jump to a conclusion that the internal front tank check valve is bad.  Clearly you have a failed dual check (shuttle) valve and at least one bad tank check valve but it might not be the front tank check valve.  The reason why I say that is with a failed dual check valve and let's say a rear dry air tank to wet tank check valve, you would also drain all tanks by opening any drain valve even with a good front tank check valve.  So, first change the dual check valve then see which or maybe both dry air tank to wet tank check valves are bad.

Frank, Thanks for keeping me straight.  I’ve order the new shuttle valve and rear tank check valve.  Once I get the shuttle valve replaced, I’ll post the results and then go from there.  

On 5/7/2023 at 8:02 AM, Frank McElroy said:

Below is a description taken from page 14 in the Bendix air brake manual in our files.

"A double check valve is used in the air system when a single function or component must receive air from, or be controlled by, the higher of two sources of pressure. An internal disc or shuttle moves in response to the higher air pressure and allows that air source to flow out of the delivery port. It is recommended that double check valves be mounted so that the shuttle (or disc) operates horizontally."

 

 

Frank,                  
Thanks for the information.  I took the valve apart and cleaned it and blew in both inlets and the shuttle moved back and forth as it’s supposed to.  I reinstalled it and started the engine to fill the tanks.  I think my check valve stuck again because no matter which  drain valves I opened, the front, rear and wet tanks drained.  I guess the tank will have to come out.  Do you know if the check valve has a part number on it?  

On 5/7/2023 at 9:21 AM, jacwjames said:

Dan,

Not sure where you live but when I had to go through my air system I wanted to replace the PTC fittings with new (just because), I checked on line but decided to make a visit to a local vendor who sells to most of the repair shop.  Took the fittings I needed down there and they just matched them up and the prices were very competitive with what I could get on the internet but these were good quality. 

I did have one hose that came in at an angle and even with a new PTC fitting I could not get it to seal.  I could added some hose with a union but I ended up buying a compression type fitting which fixed the leak the first time. 

I live near Knoxville TN and I went to Royal Brass, so check around close to you on your options. 

Jim,                 
Thanks for the suggestion.  I live in Virginia between Richmond and Norfolk, so I’m sure there is somewhere to get new fittings.  It’s going to be a busy week…

Well, I finally got the shuttle valve removed.  I had to cut one of the hoses because the PTC connector would not release.  After I got the valve out of the tank, I looked at it and figured out how it works.  It makes more sense when you can actually see something.  The name doesn’t do it any justice - 2 way check valve.  I’ve attached a photo of the valve.                       
Tomorrow I tackle the valve at the rear tank - I think….