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TR4 · 07-24-2016, 08:10 PM

Thanks twinboat, I'll run the test tomorrow and report back.

Brett, sorry not trying to hijack this thread, but we might have a similar problem. I just pulled out the pneumatic systems blueprint, and will study it to figure out where all the connections are.

Bill

TR4 · 07-25-2016, 08:22 AM

OK, after looking at the original pneumatic plans, I see no check valve between the dyer and wet tank. It is only after the wet tank to the other tanks that I see them. This is probably why Brett's gauges are not moving. The red and green tanks behind the check valves are holding pressure but the wet tank is loosing pressure, sending the signal to the governor even though the other tanks are full.

It also appears the ride height system is plumbed off the wet tank.

If there is a check valve between the dyer and wet tank, could it be in the dryer (part of it)?

Also, the signal line from the governor to wet tank tees off to a 70 lb. pressure protector and on to the air horns.

Bill

twinboat · 07-25-2016, 09:13 AM

Quote:

Originally Posted by TR4

OK, after looking at the original pneumatic plans, I see no check valve between the dyer and wet tank. It is only after the wet tank to the other tanks that I see them. This is probably why Brett's gauges are not moving. The red and green tanks behind the check valves are holding pressure but the wet tank is loosing pressure, sending the signal to the governor even though the other tanks are full.

It also appears the ride height system is plumbed off the wet tank.

If there is a check valve between the dyer and wet tank, could it be in the dryer (part of it)?

Also, the signal line from the governor to wet tank tees off to a 70 lb. pressure protector and on to the air horns.

Bill

There has to be a check somewhere between the dryer and wet tank, otherwise it would purge, to empty, every time the dryer cycles.

The air horn is probably the coach builders tee in. But now another line and control to check, along with The ride height system.

Best bet is to gauge the wet tank for troubleshooting. See if air loss stops, below 70 PSI.

Good luck

TR4 · 07-25-2016, 02:13 PM

Quote:

Originally Posted by twinboat

There has to be a check somewhere between the dryer and wet tank, otherwise it would purge, to empty, every time the dryer cycles.

The air horn is probably the coach builders tee in. But now another line and control to check, along with The ride height system.

Best bet is to gauge the wet tank for troubleshooting. See if air loss stops, below 70 PSI.

Good luck

Twinboat,

Found the check valve. It's built into the dryer on the output side. I'm starting to think the problem is somewhere in the ride height system. It takes air from the wet tank. The line going to the air ride system is protected by a pressure protection valve in case of a major leak. But a small leak would cause a drop in pressure in the wet tank and cause the system to cycle.

My other tanks are isolated from the wet tank by check valves.
My air gauges don't have much movement (They do not monitor the wet tank).
My dryer doesn't cycle after purging when parked. I'm thinking movement in the suspension is causing the ride height system to use or loose a lot of air from the wet tank.

I'll start checking the dryer check valve and all lines connected to the wet tank. I'll also check all air ride components for leaks.

Bill

Spk64 · 07-25-2016, 02:18 PM

I had a rear ride height valve leaking last year that was caused short cycling on my compressor.
But mine is coming off the secondary tank going from memory and my gauges would show the cycling. Went from 90 seconds with leak to 20 minutes without leak when going down highway.

The leak only happened when height was at certain locations. When I finally caught it leaking air it was rushing out quickly when parked. Most of the time it acted normal when parked.

twinboat · 07-25-2016, 02:23 PM

It seems an odd setup. You could have a major failure in the ride control and not know it until your compressor burned out or your MH dropped.

The wet tank is, in my experince, always the smaller tank.

bneukam · 07-25-2016, 04:50 PM

Bill,
When you say built into the dryer do you mean in the actual housing, or mounted on the outside of the dryer?

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Ray,IN · 07-25-2016, 05:41 PM

Just a thought; my rear ride-height valve began leaking while airing-up the air bags and take a long time to reach 100 psi, after psi reaches 100 it stops leaking and reaches the high cutout pressure quickly.
I've never noticed the purge cycle during this.
I asked my SIL ( maintenance manager for a nationwide trucking co) and he said the system has "gunk" in it (oil N water mix) and needs cleaning, but that height valve is probably ruined. I don't know any more, he is coming to work on it when he is home long enough and has time.
He also told me the cause was not replacing the desiccant filter per the maintenance schedule. That is likely true, because when I bought this 2000 MH in 2013, I discovered that filter had never been changed.

TR4 · 07-25-2016, 10:45 PM

Quote:

Originally Posted by Spk64

I had a rear ride height valve leaking last year that was caused short cycling on my compressor.
But mine is coming off the secondary tank going from memory and my gauges would show the cycling. Went from 90 seconds with leak to 20 minutes without leak when going down highway.

The leak only happened when height was at certain locations. When I finally caught it leaking air it was rushing out quickly when parked. Most of the time it acted normal when parked.

I'm thinking I have a similar problem. I just don't know how to test for this.

Twinboat, there is a pressure protection valve to shut down the air ride system with a major leak.

Brett, I looked up the air dyer and it shows the check valve on the output of the dyer (in the dyer) BENDIX AD-IP INTEGRAL PURGE AIR DRYER MANUAL Pdf Download.. I think it was on page 3.

Ray,IN , I'll try airing up from empty tanks and check for leaks.

I went under the coach and confirmed the air ride system is plumbed off the wet tank.

Bill

bneukam · 07-27-2016, 06:28 PM

Bill,
Did you recently replace your air dryer. If so did your symptoms start right after?

I headed out for the Oregon coast today, and I was really paying attention to my drier purging. It seemed to purge less on very smooth roads....about every 7 min. Then on rough roads with dips it was about every 2 min.

I have sprayed the heck out of my ride height control valves with no sign of leaking going on. Wondering if they could be leaking only going down the road, and leaking worse on rough roads.

I have an appointment at CC on the 2nd to see what they say.

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CC Driver · 07-27-2016, 07:19 PM

I think I hate this forum. I didn't know I had a problem until I read this thread..

On my trip today, I paid attention to the purge valve going off, and it's every 30 sec to 1 min while driving.ONLY, not while parked

.

"I headed out for the Oregon coast today......"

Brett, we passed each other just west of Pendleton about 2:30 today. Saw you and told the wife, I'll bet that was Brett. Too funny. I was headed back to Caldwell..

Guess now I'll have to start looking for a leak...

TQ60 · 07-27-2016, 07:34 PM

Driving down the road will cause suspension to move.

That causes air to be released as wheels go one way and air to be needed to replace it as the wheel returns.

A valve with internal parts slightly out of adjustment will leak more but that is another story.

You can test by having helper listen next to wheels while a few folks walk around inside to see if all 4 corners act the same.

Engine off of course and full air at ride height.

TR4 · 07-27-2016, 08:26 PM

Quote:

Originally Posted by bneukam

Bill,
Did you recently replace your air dryer. If so did your symptoms start right after?

I headed out for the Oregon coast today, and I was really paying attention to my drier purging. It seemed to purge less on very smooth roads....about every 7 min. Then on rough roads with dips it was about every 2 min.

I have sprayed the heck out of my ride height control valves with no sign of leaking going on. Wondering if they could be leaking only going down the road, and leaking worse on rough roads.

I have an appointment at CC on the 2nd to see what they say.

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Brett, I've always had this problem and I think your right. Rough roads seam to cause it to cycle more often. This might be causing the ride height control valves to over compensate. I remember reading on the Yahoo Country Coach forum that a member added larger auxiliary tank for the suspension to cut down cycle time.

I don't know if this is normal, and hearing CC Driver having the same problem, maybe this just the way the air ride works.

Anyway, today I replaced the Bendix AD-IP dryer with a rebuilt unit. Leaving on a trip to Yosemite in two weeks. I'll see if things get better.

I think it would be good to hear from other members on cycle times for their air dryers.

Bill

bneukam · 07-27-2016, 08:32 PM

Tom,
We saw you as well.

Sorry about this forum, you can blame me. Sounds as if it's pretty common problem. Personally I would love to have a gauge on the inside for the wet tank. You really have to be paying attention to hear the drier purging off when your flying down the road.

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