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Air System Leak on Freightliner Chassis

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10 hours ago, WILDEBILL308 said:

This must be the season for air leaks. I just had to replace the same main air hose but I was alongside the road on 30 just east of Plymouth Indiana. 

Bill

Ugg, on the side of the road none the less. Glad you were able to locate it, did you do it yourself? To bad Plymouth Indiana, if Plymouth Massachusetts I would have came over to help. We are here for two more days.

 

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13 hours ago, jleamont said:

Ugg, on the side of the road none the less. Glad you were able to locate it, did you do it yourself? To bad Plymouth Indiana, if Plymouth Massachusetts I would have came over to help. We are here for two more days.

 

No unfortunately I couldn't hear the leak. I was thinking it might be the dryer cartridge plugged up or something in that area. So I called Coach Net and had them send out a mecanic. Well He by passed the dryer and that wasn't it.  He finally found the leak where the hose is hidden in a bunch of wiring bundles on the right side of the engine. Well he didn't have a hose so he tried to patch the hose. I was scheduled to stay in Fort Wayne that night and figured if I could get to the park I could find a new hose.

Well he got it to hold pressure and we started to head out. I was going to drive around the block to get back on the main road and didn't make it. Lost pressure and the brakes clamped down. Called Coach Net again and told them to send the mecanic back as his repair didn't hold. While we were waiting I decided to see what I could do. I ended up re doing the patch and another spot that was leaking and had it holding pressure when the mechanic returned. He had a new hose this time so I told him to replace it (a new hose trumps a twise repaired hose). It was about 1:30AM  and I didn't feel like driving to Fort Wayne so we went  back to a Pilot about 6 miles west. 

Bill 

 

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:o

Those flexible lines have an internal sleeve, Teflon lined inner tube, once it's compromised you are done.

Glad he was able to fix it, mine had to be specially made. 

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My question is: Where does the air go when I leave my coach for a few days? My wife says she hears a slight hiss under the dash. Is there some kind of relief valve that slowly bleeds the system? I checked my air pressure lines to the gauge and the gauge itself, everything looks fine. Any ideas?

2007 Winebago Tour

Cummings 400 HP  ISL

This my 7th Motorhome, 1st diesel.

 

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3 hours ago, nz8y00 said:

My question is: Where does the air go when I leave my coach for a few days? My wife says she hears a slight hiss under the dash. Is there some kind of relief valve that slowly bleeds the system? I checked my air pressure lines to the gauge and the gauge itself, everything looks fine. Any ideas?

2007 Winebago Tour

Cummings 400 HP  ISL

This my 7th Motorhome, 1st diesel.

 

nz8y00, Welcome to the forum.

Those aren't the only air lines. Check the dump valve and the brake valve. You can use a length of hose like a stethoscope to help find leaks.

Bill

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I'm with Wildebill, check the dump valve.  Since it is located under the coach it gets a lot of road grit thrown at it and a small piece of sand could be causing the valve to leak just enough to let your air out overnight.

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Thanks, I will check the dump valve and brake valve. Does your coach loose any air in a 24 hour period? Just wondering if the air system is supposed to bleed slowly when sitting.

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2 hours ago, nz8y00 said:

Thanks, I will check the dump valve and brake valve. Does your coach loose any air in a 24 hour period? Just wondering if the air system is supposed to bleed slowly when sitting.

How much does the air pressure drop in 24 hrs.? You might be able to find the leak(s) by spraying the airline connections with some soapy water and look for air bubbles.

Rich.

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Just a thought all air systems lose air pressure over time. The question is "what is the acceptable rate". You might need to call the manufacturer and see what that is. Most (unless you have air leveling) coaches tell you to dump air when parked. You may be wasting your time chasing leaks if they are within limits.

Bill

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I will loose 30 lbs of pressure over 6 days in the summer, in the winter it's 2x faster.

When I pull in to where I'm going to stay I feather the brakes until the governor kicks in, I let it build air, when the dryer purges I shut it down, set up, (water, electric, sewer, cable tv line, slides out) then dump the air suspension and press the level button. I need as much air as possible to pick that beast up to level it. 

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1 hour ago, jleamont said:

I will loose 30 lbs of pressure over 6 days in the summer, in the winter it's 2x faster.

When I pull in to where I'm going to stay I feather the brakes until the governor kicks in, I let it build air, when the dryer purges I shut it down, set up, (water, electric, sewer, cable tv line, slides out) then dump the air suspension and press the level button. I need as much air as possible to pick that beast up to level it. 

Don't you have a auxiliary air compressor for the air leaving system?

Bill

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9 hours ago, WILDEBILL308 said:

Don't you have a auxiliary air compressor for the air leaving system?

Bill

Yup, it only supplies the leveling system, the tanks will still fade out over time, but the coach will not sink. I have no idea how it works yet, other than when the coach runs out of air and you push a button on the HWH pad you can hear a compressor turn on, but it is much-much slower than the main air supply system to reposition the coach.

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1 hour ago, jleamont said:

Yup, it only supplies the leveling system, the tanks will still fade out over time, but the coach will not sink. I have no idea how it works yet, other than when the coach runs out of air and you push a button on the HWH pad you can hear a compressor turn on, but it is much-much slower than the main air supply system to reposition the coach.

Joe, The points of air leaks on our coach have been, the main supply line between the compressor and dryer(slowly kept getting worse), The primary tank manual drain valve and the air ride springs that where around 12+ years old when the air loose became noticeable. At the present time the air pressure only drops around 10 to 15 psi over 24 hrs. Note! this can very depending on how many times we enter and exit the coach with the system aired up as the ride height system tries to keep the coach level. Ride height adjustment set properly also reduces air loose in our secondary air supply tank.

When the primary air line from the compressor and the air dryer was replaced the air up time was reduced. Leeks tend to start small and we just tend to accept it until you know its just taking to long to recover the top pressure set by the governor.

Rich.

No aux. air pump on our old girl.

 

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16 minutes ago, Dickandlois said:

Joe, The points of air leaks on our coach have been, the main supply line between the compressor and dryer(slowly kept getting worse), The primary tank manual drain valve and the air ride springs that where around 12+ years old when the air loose became noticeable. At the present time the air pressure only drops around 10 to 15 psi over 24 hrs. Note! this can very depending on how many times we enter and exit the coach with the system aired up as the ride height system tries to keep the coach level.

Rich.

 

Rich, good point about how many times we enter and exit, ours will also compensate. funny story; I was cleaning up inside and moving stuff around Saturday, DW was sitting under the awning and it exhausted air near her, she came up out of the chair leaned inside and asked me if I thought that was funny :huh:. I tend to be a practical joker but I was innocent on that one :lol:.

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Joe, do you have both air level and jack, independent off each other? 

When I level by air, I loose only the amount that is need for front/rear and corner/corner,  the main pump comes on about every 24 hours, to maintain level.  When I choose to use the Jacks, all air goes at one time (purge system).  The air supply, then comes on after Jacks have been retracted and I start engine...slides will not operate with engine running.

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Just making sure that the coach is still level and her Adrenalin system is still working.  It is much easier to roll around under the coach on the creeper with the coach aired up, but if the system does a leveling cycle - it gets your attention! LOL

Rich.

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I have a 12 Tiffin Open Road 340 cummins and have discovered that the NORGREEN solenoid valve is leaking on the passenger side.    The left doesn't leak.  It also appears that the air leak is somehwere between the right side block and main part of the valve.   Is this normal for a small leak?  I have the NORGREEN A16 18694 00 twin solenoid valve.

 

Edited by f318927

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50 minutes ago, f318927 said:

I have a 12 Tiffin Open Road 340 cummins and have discovered that the NORGREEN solenoid valve is leaking on the passenger side.    The left doesn't leak.  It also appears that the air leak is somehwere between the right side block and main part of the valve.   Is this normal for a small leak?  I have the NORGREEN A16 18694 00 twin solenoid valve.

 

Just a note this post is 6 years old You can often learn things reading the older post but seenthat poster for a  while. 

I like using the kids bubble mix to hunt for air leaks. It might be nothing but a loose connection. Even if the line is cut it isn't that hard to replace.

Use appropriate safety measures when working under a coach.

Let us know what you find.

Bill

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Does anyone know if this dump valve can be rebuilt with O rings?    The valve is actually leaking between the electronic module on the right and the silver main frame.   I can see the C Lock rings which tells me the valve does disassemble.      

1620522381.jpg

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On 10/10/2022 at 2:07 PM, f318927 said:

Does anyone know if this dump valve can be rebuilt with O rings?    The valve is actually leaking between the electronic module on the right and the silver main frame.   I can see the C Lock rings which tells me the valve does disassemble.      

1620522381.jpg

At $547.33 each, I believe I'd rebuild the present one. If a rebuild fails, then grab your credit card.

FWIW, I fixed my dump valve by simply removing the compressed air intake line and adding a few drops of air tool oil. I guess it lubricated the O-rings and seals enough to stop the air leaking. (do not use motor oil)

Edited by rayin

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