Air Leak

[vanwill52]

12 hours ago, 96 EVO said:

If your implying I'm wrong, just say it!

That diagram is my drain manifold. I know exactly what each of them are!

Not implying, or trying to, at all.  Just that there are some folks here with an incredible skill set, that are always worth listening to.  No offense intended.

[Guest Ray Davis]

Ya know,  we don't all automatically get along with each other,  but we should try.

Personally,  I think Ben and Van both should have been on that list.   I listen up when either makes a post.

We are not all endowed with astounding knowledge as some of the guys obviously are,  I marvel at the things you guys understand and can do.   Actually,  I have known a couple of geniuses that in many ways seemed dumb, none like that here of course,  or is there?   😁

Sure, there are folks that annoy me and I'm sure I annoy some too,   but I hope I don't say something hurtful to anyone.  One thing I don't need to do is lose friends.  I'm losing too many that are passing away.  

Things used to get testy on the forum and Bill D would say running the forum was like herding cats.    LOL

Edited May 9, 2023 by Ray Davis

[Tom Cherry]

Things seem OK and we’ll just keep rocking long.  For those that didn’t know the Colonel…..and Fred White, who inherited this “entity”….Fred had a great relationship with the Colonel and there were three of us with “credentials”.  Every once in a while, as well as after the Colonel’s passing we would have a situation come up and I would talk to Fred….and make a suggestion.  He would chuckle and say the Colonel was all military to the end….when he got upset about something, it was “READY; AIM; FIRE”…..then ask a question or try to understand or defuse….Fred’s approach was softer and more subdued…..which, personally, I DO try to follow and discuss some issues or irregularities with Frank, more often, as well as Scotty… In some ways, the wisdom and spirit of our founders lives on….good summary of the Colonel….”most of the time”  Double LOL!

 

Things used to get testy on the forum and Bill D would say running the forum was like herding cats.    LOL
 

[dandick66]

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

[RoadTripper2084]

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?

 

[96 EVO]

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

[Frank McElroy]

42 minutes ago, dandick66 said:

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

Good, your data confirmed that the front wet/dry tank internal check valve is good.  For sure, that would be the hardest valve to change.  I was kind of suspicious that the front tank valve might be OK because in one other test, it held air.  Depending on where that dual check shuttle valve sticks, the tank with the good check valve will hold air.  Your testing confirmed that only the rear tank has the bad check valve 

[dandick66]

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…

[vanwill52]

The postmortem would be most welcomed.  Too often we (me included) fail to report back the solution that many members have helped us find.  You write very well.  I'm sure your final report will be very valuable.

[96 EVO]

45 minutes ago, dandick66 said:

I will do a postmortem once everything is fixed.

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…

Up here, 16hrs of classroom learning, followed by a written, and practical test before you can legally drive an airbrake equipped vehicle!

It's much tougher when your laying under a coach, than seeing all the parts mounted to a large board! 

[dandick66]

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

[96 EVO]

Yes, that is very strange!

If you have good access to your dryer, just hold your hand under the purge valve.

After the compressor unloads, you 'should' feel low pressure air coming out for 9-14 seconds.

[Bill R]

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. 

[96 EVO]

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

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

[dandick66]

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.  

[96 EVO]

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.

Edited May 14, 2023 by 96 EVO

[dandick66]

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.  

[96 EVO]

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

[dandick66]

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.

[Bill R]

@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.

[Frank McElroy]

On 5/14/2023 at 4:59 PM, dandick66 said:

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/

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.  

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.

[96 EVO]

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.

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!

[dandick66]

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…

[Frank McElroy]

1 hour ago, dandick66 said:

 

 

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…

I would be very careful in changing an brake line air hose diameter from the OEM original design.  The system was designed to meet DOT standards for certain air flow rates for the speed in which the brake chambers respond, in a balanced way, for rapid brake setting, 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.

For the above reasons, the leaking 1/2" air hose needs to be replaced with another 1/2" air hose.

[dandick66]

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.