Air dumping from rear under acceleration.

Topic: Air dumping from rear under acceleration. (Read 1852 times) previous topic - next topic

Re: Air dumping from rear under acceleration.

Reply #25 – August 24, 2018, 05:42:22 pm

My understanding is that the max D2 is 135.

Is not the DOT max on fittings 150?

Re: Air dumping from rear under acceleration.

Reply #26 – August 25, 2018, 02:34:18 pm

Quote from: John44 – August 23, 2018, 10:14:44 am

Mike J,with all the trouble you have had I would just get a new D-2 valve and install it,they are availible everywhere and is one of the
parts you should have a spare for.They are usually preset at 120 to 130 psi so you should never have any pressure more then that.

Thanks all. We are heading towards Moscow Idaho today. Flat roads and easy drive on route we have chosen. Good time for me to get an accurate read on the air pressures in front and rear tank. My better half is doing all the driving and when we were in the mountains she wasn't watching the air all that closely and my view is at an oblique angle. (We do not have a gauge on the wet tank.)

D2 valve is now on my list. Will see where I can get one as spare/installed if front or rear tank pressure is really as high as 150psi. After reading Beamalarm link it is surely time to service/replace it given mileage and/or time. I'm pretty sure that current one is the OEM from 2002 coach build as there are no records from PO on replacing it.

Other info: After 24 hours both front/rear tanks read 40psi. No aux compressor run time either. Fixing leaks in six packs and other fittings/regulators seems to be keeping us parked level. Coach wouldn't do that before. Previously dropped in front.

Re: Air dumping from rear under acceleration.

Reply #27 – August 25, 2018, 03:04:12 pm

Quote from: Mike J – August 25, 2018, 02:34:18 pm

Other info:
1. After 24 hours both front/rear tanks read 40psi.
2. No aux compressor run time either
3. Fixing leaks in six packs and other fittings/regulators seems to be keeping us parked level.

If your air system bleeds down to 40 psi in 24 hrs, you do still have some leaks, somewhere. Not something you necessarily need to worry about - lots of coaches will do the same exact thing. it's just a question of how much time/money/effort you want to devote to chasing small leaks.

Your aux compressor is not running because your coach is remaining level when parked. The compressor will run if your system air pressure is low AND if the HWH control box thinks it needs to increase the pressure in one or more bags to keep coach level.

Replacing the D2 regulator certainly won't hurt anything. NAPA stores will always have them in stock. R&R can be a simple job, or a difficult job, depending on the location of the D2. Having a spare D2 in your parts box is a very good idea. They seem to always act up at inconvenient times and places.

Re: Air dumping from rear under acceleration.

Reply #28 – August 26, 2018, 09:42:26 pm

The 150 psi and air purging intervals I reported in my previous posts was incorrect. My apologies! New mechanical gauge faces are numbered differently. Regardless, that's no excuse for misreading the new gauge. Feeling like a newbie.

Confirmed following during a 20 mile run yesterday. Level ground, 58-60 mph, usually on cruise, approx 1550rpm. With a stopwatch I timed the purging of air and watched closely the psi levels. Air exhausts at 128 psi every 1.5-2.5 minutes. On rougher road the interval between purges increases to 3-3.5 minutes. Front tank stays pretty consistent at 110-120. It will drop to 95-100 before climbing again to 110-120. The rear tank has the largest swings and they are not always in sync with psi in the front tank. Rear tank drops to 95 then rises to 128 before we hear air is purged. Sometimes the front will vary 100-120 while the rear goes from 95-128. No inverter or service brakes were applied during this test run.

Selected travel mode at start up, cold engine idle: both tanks build pressure within 5 psi of each other. Once at travel mode, the front tank psi moves very little off of 110-120, however the rear tank cycles. At warm engine idle it takes 4.5 minutes for pressure to drop from 128 to 90 psi. Pressure takes 1 minute to build from 90 to 128 psi. Have noticed a louder noise (a kind of metallic clatter different from my memory of the sound of Cummins idling). Sound more pronounced after engine warms up. Comes from rear of coach, most noticeable in bedroom area just behind rear axle. Sound builds as the psi approaches the 128 psi purge level and also when approaching the lowest psi of 90. Easy to hear when coach is idling as compared to when driving.

We leveled the coach, allowed tank pressures to build and shut down engine immediately after air purged. Within five minutes rear tank psi dropped from 128 to 60. Front tank stayed at 110 psi. Twenty minutes later front at 100 and rear at 60psi.

Now in Moscow Idaho, will run errands tomorrow in the toad. Look for a D2. Would appreciate a NAPA part number. I'll check for one online as well in case no one replies here before tomorrow. Not sure where to find someone who can install it correctly and/or if it will have proper psi levels preset. (should be on the part or box?) I recall forum members saying this replacement is easy. I'm not as confident given I have to rely on others to do the wrench turning.

Truly appreciate all the help. We both are looking forward to having these air issues behind us. Being newbies it is disconcerting, listening for anything unusual. The learning curve is stressful at times. Sorry for the lengthy post.

Re: Air dumping from rear under acceleration.

Reply #29 – August 26, 2018, 09:51:24 pm

Quote from: Mike J – August 26, 2018, 09:42:26 pm

The 150 psi and air purging intervals I reported in my previous posts was incorrect. My apologies! New mechanical gauge faces are numbered differently. Regardless, that's no excuse for misreading the new gauge. Feeling like a newbie.

Confirmed following during a 20 mile run yesterday. Level ground, 58-60 mph, usually on cruise, approx 1550rpm. With a stopwatch I timed the purging of air and watched closely the psi levels. Air exhausts at 128 psi every 1.5-2.5 minutes. On rougher road the interval between purges increases to 3-3.5 minutes. Front tank stays pretty consistent at 110-120. It will drop to 95-100 before climbing again to 110-120. The rear tank has the largest swings and they are not always in sync with psi in the front tank. Rear tank drops to 95 then rises to 128 before we hear air is purged. Sometimes the front will vary 100-120 while the rear goes from 95-128. No inverter or service brakes were applied during this test run.

Selected travel mode at start up, cold engine idle: both tanks build pressure within 5 psi of each other. Once at travel mode, the front tank psi moves very little off of 110-120, however the rear tank cycles. At warm engine idle it takes 4.5 minutes for pressure to drop from 128 to 90 psi. Pressure takes 1 minute to build from 90 to 128 psi. Have noticed a louder noise (a kind of metallic clatter different from my memory of the sound of Cummins idling). Sound more pronounced after engine warms up. Comes from rear of coach, most noticeable in bedroom area just behind rear axle. Sound builds as the psi approaches the 128 psi purge level and also when approaching the lowest psi of 90. Easy to hear when coach is idling as compared to when driving.

We leveled the coach, allowed tank pressures to build and shut down engine immediately after air purged. Within five minutes rear tank psi dropped from 128 to 60. Front tank stayed at 110 psi. Twenty minutes later front at 100 and rear at 60psi.

Now in Moscow Idaho, will run errands tomorrow in the toad. Look for a D2. Would appreciate a NAPA part number. I'll check for one online as well in case no one replies here before tomorrow. Not sure where to find someone who can install it correctly and/or if it will have proper psi levels preset. (should be on the part or box?) I recall forum members saying this replacement is easy. I'm not as confident given I have to rely on others to do the wrench turning.

Truly appreciate all the help. We both are looking forward to having these air issues behind us. Being newbies it is disconcerting, listening for anything unusual. The learning curve is stressful at times. Sorry for the lengthy post.

You have a leak in the rear. The D-2 is not the problem. Your protection valves are what stops the rear at 60psi. Run the engine and get the pressures up to the cutoff and shut off the engine. Go to the rear and listen for air escaping. If you cant hear it, get a squirt bottle and put some dish soap and water in it and start spraying the air bags etc.

Re: Air dumping from rear under acceleration.

Reply #30 – August 26, 2018, 10:54:46 pm

D2 governor NAPA part numbers, either one would work fine:

https://www.napaonline.com/en/p/TWRBENOR284358X

https://www.napaonline.com/en/p/TWRBENOR275491X

Re: Air dumping from rear under acceleration.

Reply #31 – August 26, 2018, 10:56:26 pm

Quote from: Mike J – August 26, 2018, 09:42:26 pm

Now in Moscow Idaho

HWH is in Moscow, Iowa. They will check your system out, but you will *need* an appointment.

Trent

Re: Air dumping from rear under acceleration.

Reply #32 – August 26, 2018, 11:22:26 pm

Quote from: Mike J – August 26, 2018, 09:42:26 pm

We leveled the coach, allowed tank pressures to build and shut down engine immediately after air purged. Within five minutes rear tank psi dropped from 128 to 60. Front tank stayed at 110 psi. Twenty minutes later front at 100 and rear at 60psi.

Yes, like The Other Chuck says, you are losing air out of your "rear" tank. Not the "wet" tank, which is in the rear, but the "rear" tank, which is in the front.

Your air compressor is cycling in and out more rapidly than would be normal because it is having to keep up with the air leak. You can drive this way - you are not going to damage your air compressor. As long as the compressor can still build to cut-out pressure, you are OK. If the leak were to become more serious, to the point that the compressor could never reach cut-out pressure but just ran continuously, then you would for sure need to get the leak fixed. But for now, you can live with it until it is more convenient to get it looked at.

It sounds like your D2 governor is working fine. I agree with The Other Chuck, don't think you need to worry about changing it out at this time. If you want to buy one to carry as a spare, some NAPA part numbers are listed in reply #30 above.

The best way to approach looking for any leak, is to first get out your air system diagram. You need to look at what lines come off the "rear" tank...where does the air go. Then you have to think about each place the air from that tank is used, what path the air follows to get there, and try to figure out best way to check for leaks. It is not easy, especially as you say if you have to depend on mechanics who may not be familiar with the air system on your coach.

Re: Air dumping from rear under acceleration.

Reply #33 – August 26, 2018, 11:26:25 pm

Quote from: TulsaTrent – August 26, 2018, 10:56:26 pm

HWH is in Moscow, Iowa.

Mike J is in Moscow, IDAHO

Re: Air dumping from rear under acceleration.

Reply #34 – August 27, 2018, 12:57:23 am

Quote from: Chuck & Jeannie – August 26, 2018, 11:26:25 pm

Mike J is in Moscow, IDAHO

Chuck,

I already knew that. Because of the unusual city name, I was pointing out that he could get service from the factory, in another city named the same, but several states East of his location.

Many Foretravel owners, including me, have benefited from taking their Foretravels to HWH, in Moscow. I was suggesting that he might benefit from making an appointment with them as part of his travels.

He is one of our newer members and may not have known about HWH. He may not be able to do that during his current trip.

I probably should have found a link to HWH factory discussions on the forum, but am beginning to lose interest in this topic; it is past my bedtime.

Trent

Re: Air dumping from rear under acceleration.

Reply #35 – August 27, 2018, 08:15:47 am

Quote from: TulsaTrent – August 27, 2018, 12:57:23 am

Chuck,
I already knew that.
Trent

OK, sorry! Mike J is already getting so much info overload - I didn't want him to confuse the 2 cities. Your idea about swinging past the HWH home office is excellent, if there is any way he could include the stop in this trip. Or the next one.

Here is one report on a HWH factory visit. There are others - all have a similar complimentary tone.

Good Experience with HWH in Moscow, Iowa

Re: Air dumping from rear under acceleration.

Reply #36 – August 27, 2018, 08:32:47 am

I found out about Moscow ID on our recent trip to Yellowstone. Someone we met was going from there to Moscow; I assumed he was talking about Moscow OH, but not. Wonder how many states have cities named Moscow; and why?

Trent

Re: Air dumping from rear under acceleration.

Reply #37 – August 27, 2018, 08:39:03 am

Quote from: TulsaTrent – August 27, 2018, 08:32:47 am

Wonder how many states have cities named Moscow; and why?

Lots of Russian immigrants to this country back in the city naming days?

Here's another (better researched) attempt to answer the question:

Solving the mystery of the Moscows of America

Re: Air dumping from rear under acceleration.

Reply #38 – August 27, 2018, 08:49:11 am

Here is a bit of early morning bandwidth for breakfast.

One source says there are 18 cities known as Moscow in the United States:
- Moscow, Idaho
- Moscow, North Dakota
- Moscow, Maine
- Moscow, Kansas
- Moscow, Texas
- Moscow, Arkansas
- Moscow, Iowa
- Moscow, Minnesota
- Moscow, Wisconsin
- Moscow, Michigan
- Moscow, Indiana
- Moscow, Ohio
- Moscow, Kentucky
- Moscow, Tennessee
- Moscow, Mississippi
- Moscow, Virginia
- Moscow, Maryland
- Moscow, Pennsylvania
If you count places that smaller then apparently 21.

There are only 18 places named Hastings in the US. Go figure.

There is one place in the world named Nacogdoches!

Re: Air dumping from rear under acceleration.

Reply #39 – August 27, 2018, 02:18:53 pm

Good morning.

Roger, So many Moscows! I'll get out the Garmin and see if we can visit all of them. I enjoyed having a good laugh this morning after reading your post. I think a visit to HWH in Iowa would be smart. Have to see where it fits. We're hoping our 2 remaining months of traveling don't become a journey to service centers instead of touring the country.

I agree the rear tank is place to start looking, (which I know is mounted in front). Any connection on/to it as well as where those lines come from and those connections. Doubt it could be an airbag as coach does travel mode correctly and it levels properly as well. This morning psi at 42 in both front and rear tanks. Before recent repairs the coach used to drop in front within a day and rear settled in a week and we rarely heard dryer purge during driving. Fixed 14 leaks and we now stay level for several days without aux compressor ever running and air dryer does purge often enough, 2-3 minutes, to notice it while driving.

What am I missing? Appreciate everyone's input!
I sure would like to know why leakdown in rear tank is most evident with engine compressor running and also when coach is first leveled and both tanks are at maximum psi. With engine warm, where does the clattering/chatter noise come from at the low and high, (louder) end of air psi range. And why is rear tank leakdown most evident when psi reaches level where air dryer purges.

Thanks! (I'm not looking to fix all leaks. Just think this leakdown in rear tank seems worth finding)

Re: Air dumping from rear under acceleration.

Reply #40 – August 27, 2018, 03:39:11 pm

Quote from: Mike J – August 27, 2018, 02:18:53 pm

I sure would like to know why leakdown in rear tank is most evident with engine compressor running and also when coach is first leveled and both tanks are at maximum psi. With engine warm, where does the clattering/chatter noise come from at the low and high, (louder) end of air psi range. And why is rear tank leakdown most evident when psi reaches level where air dryer purges.

Mike,

First thing that comes to mind is the check valve that is at the rear tank has failed and is leaking back through. This check valve is where the air line goes into the tank boss. You may also have the internal check valve at the dryer discharge that has been installed up side down (yes even on a fresh factory rebuilt dryer I have seen it happen) causing the air to backfeed out to atmosphere through the drain on the dryer.

Mike

Re: Air dumping from rear under acceleration.

Reply #41 – August 27, 2018, 03:41:28 pm

Have you been to the engine compartment during the start and stop of the compressor? The unloader valves in the compressor could be making the noise. It would not cause the leak though. The compressor stops making pressure at the top end and doesn't start again until the low end. I have had a belt on my air compressor make such a noise also.

Re: Air dumping from rear under acceleration.

Reply #42 – August 27, 2018, 07:03:23 pm

Went to engine compartment to check sound of compressor. Ended up finding a fairly loud air leak behind drivers side rear duals. Leak is very easy to hear standing next to coach after turning engine off. Can hear it for at least 10 minutes. Seems to come from where ride height valve is or possibly further in toward center of coach. Can't reach in there with soap spray, there is a storage compartment blocking access, unlike easy access on passenger side where air dryer and chassis battery are.

Noises, clattering rattle still present. Metallic sound. Stops clatter/rattle when air dryer purges.

Tomorrow taking it to a heavy equipment shop to see where air leak is. Only option that is close to our location.

Re: Air dumping from rear under acceleration.

Reply #43 – August 27, 2018, 07:34:13 pm

Quote from: Pamela & Mike – August 27, 2018, 03:39:11 pm

Mike,

First thing that comes to mind is the check valve that is at the rear tank has failed and is leaking back through. This check valve is where the air line goes into the tank boss. You may also have the internal check valve at the dryer discharge that has been installed up side down (yes even on a fresh factory rebuilt dryer I have seen it happen) causing the air to backfeed out to atmosphere through the drain on the dryer.

Mike

It would be very surprising to me too if the internal check valve is upside down. The air dryer we now have installed is the original OEM Haldex Pure Air. Only the filters/desiccant were changed out, (done about six months ago). The new/rebuilt dryers we had tried two weeks ago had wrong psi purge valve installed. They caused the original problem of this thread.

Thinking new leak we found today has different origin. Somebody will be under there tomorrow with a soap spray looking for bubbles. Will also ask what they think of clattering noise before dryer purges. Coach staying level now even after new leak ceases to be heard. F/R tank at 45 psi.

Re: Air dumping from rear under acceleration.

Reply #44 – August 27, 2018, 09:35:46 pm

The noise is the unloader valve most likely and should stop when pressure is requested by the pressure controller D 2 . Check for a compressor line hose leak into the dryer . Or the unloader line .

Re: Air dumping from rear under acceleration.

Reply #45 – August 27, 2018, 10:43:09 pm

Regarding the air leak near driver side duals...I'm just guessing here...

Do you have a remote mounted wet tank water drain valve? On our coach, the drain valve is mounted just ahead of the driver side duals, on the bottom edge of the wheel well. If yours is in the same general location, perhaps the nylon air line running from the wet tank to the drain valve was damaged in some way, and is leaking. A leak in that line would bleed air pressure off the wet tank, and could also bleed air pressure off the "front" and/or "rear" tanks, if the check valve at the tank inlet is faulty (a not uncommon condition).

Re: Air dumping from rear under acceleration.

Reply #46 – August 31, 2018, 09:33:20 pm

Hi Chuck,

Good idea to check remote drain line.

For now, found two problems. Had airline run to coach rear 4 months ago for the air M&G brake system on our toad. Shop did sloppy job. ran airline under cross member of frame that rises and falls as suspension travels. The line would occasionally touch rotating portions of driveline. Leak just happened to show up three days after we thought we were done with the air dryer issues. Had repair done on location where we are parked by heavy farm equipment mobile service tech out of Moscow Idaho.

Air to toad is now routed with other cables along frame and then tied to existing brake can supply lines. We had to add about two feet of hose. It will now flex along with all the other lines as suspension travels. 2nd problem he found was a fitting on ride height valve that wasn't holding airline properly. Replaced it. We hope we are done now. Test drive this Saturday when we go to fuel up in town. I'll post results then.

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