Air leak basics - Printable Version
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+--- Thread: Air leak basics (/showthread.php?tid=3658)
RE: Air leak basics - Richard - 08-04-2017
Take a look at the plastic bowl on any air water separators on th coach. All of
Them crack eventually and they will leak like crazy
RE: Air leak basics - Nebster - 08-04-2017
Will do.
I spent a half hour with the Inficon last night going around, but I didn't find any indications of a leak. It's a little hard to know where to point and what to look for when I don't know the air system design very well.
Does anyone know if the slide seals get isolated from the main supply once they are inflated, or is there a continuous top-off that happens with them?
RE: Air leak basics - encantotom - 08-04-2017
to tell if your particular slide seals have live air pressure to them is simple. just turn off the compressors and as the coach air goes to zero see if your seals deflate.
and the way i use the inficon is with enclosed over the ear headphones. for me using the on the ear headphones they supplied and or the indicator light on the unit doesnt work well
tom
RE: Air leak basics - Yachts - 08-04-2017
Thank you to everyone on this thread. My compressor had been cycling every 5 minutes or so for the last few months and I hadn't been able to take the time to diagnose the problem. This evening we ran out of air and I figured I either had burned up the 110 compressor or I had a massive leak. I checked the pump and it was super hot, so I turned it off and began to look for a leak..I was losing 20-40 psi a minute..I couldnt locate a leak. If the engine was on I could hold pressiure but the 110 couldn't keep up. So I ran to Walmart bought a pancake compressor stuck it in the stacker plugged it into the coach and it couldn't keep up either. So it was off to dig deep for the leak.
My brake air stayed solid even if the supply air dropped quickly so I ruled out the brake system.
I drained the water separator by the 110 compressor. Then I went under the coach betweeen the wheels and opened the petcock valve on the four tanks I could see. One had quite a bit of water the other three were bone dry. But no obvious leaks. Next I checked the air bags and the height control valves in the rear.. no leaks.. so then I checked the height control valve in the front.. it can be accessed by removing the center panel on the front side of the storage bay. I immediately heard air . But can't find where it's leaking even with soapy water. The coach was in level mode and the front was dropped down. Put the coach in travel, it raised up and the leak went away. The air pressure was now dropping at a slower rate so I had diagnosed part of the problem. I also noticed a small hyadraulic leak on one of the fittings to the steering ram.
So I checked every seal ,toilets ,air doors nothing.. then I began checking each storage bay. When I got to the water bay I heard it! We are at a campground and dumped and I forgot to close the valve back and I have a large leak when it is open.. since we never stay any where longer than a day or 2 I never hook up the sewer line for more than 10 mins. So I never knew my leak was as bad as it was.
But this thread helped me break the problem down to smaller units.. thanks to all for your help.
RE: Air leak basics - encantotom - 08-04-2017
marc, there is another thread on rebuilding the valve manifold that controls the dumps.
easy to do
tom
RE: Air leak basics - Nebster - 08-26-2017
I've been driving cross country this week and shaking out the Newell on the way. Yesterday, I walked into the coach and heard a hiss coming from the base of the Knoedler air chair. Sure enough, it sounded like a giant leak coming out of one of the valves there.
I also observed compressor cycling increased to once every 2 minutes, up from 4 or 8 minutes previously (it has varied for some reason that I don't understand).
Rather than taking the chair apart while underway, I instead snipped open the supply line and inserted a valve. Now I can turn on the air to the chair, raise the height or whatever, and then close it off. When I get home I will work on disassembling and replacing the faulty valve(s).
Anyway, I was pretty happy: compressor cycle time increased to 12 minutes, so something like 80% of the leak was just the chair!
Later today, while underway, my coach started making a burning smell. Long story short, after pulling over and a bunch of debugging and help from Newell, it turns out one of the height control valves had just sheared off its control arm linkage thing. I aired up the coach manually, limped to a service center, and we fashioned a new linkage out of miscellaneous parts and pieces. We are back in business.
Very late this evening, I pulled into an RV park and set up shop. Immediately, however, I now notice that the compressor is back to cycling every two minutes -- with the leaky chair valve shut off.
I don't know if the latter incident has anything to do with the change in leak rate, but I am starting to suspect that I am cursed. I suppose this story is To Be Continued.
RE: Air leak basics - HoosierDaddy - 08-26-2017
Damage to a HCV is somewhat rare. I would check the valve itself and lines to it. Whatever damaged the linkage may have caused a leak.
RE: Air leak basics - 77newell - 08-26-2017
The 6-pack supplies air to the HCV's on a full time basis and only controls the output of it via the "travel" solenoid valve which is open whenever in the "travel" mode. Therefore, it is possible that mechanical damage to the HCV could leak compressed air without effecting the level of the coach, it would just result in higher air consumption.
RE: Air leak basics - Richard - 08-26-2017
Jon,
I hate to disagree with you cause it means I will usually have to retract the comment. However, on all of the Newell's I have intimate knowledge, air is supplied directly to the HCV from the coach air system. The six pack is between the output of the HCV and the air bag. So if the HCV is damaged then you will lose coach air pressure rapidly.
The plastic Ridewell HCVs are well documented for splitting at the air fitting inlet and loosing copious air. @"Fulltiming" had one cracked so badly that it wouldn't bubble or trip the Infinicon.
RE: Air leak basics - 77newell - 08-27-2017
On my 93 coach, compressed air from the supply tank passes through a ball valve mounted ahead of the drive axle and splits at a tee with each of the two lines going to the center port of one of the 6-packs (front and rear). A drilled passage in the 6-pack passes the air through the base plate and out the opposite side and thence to a tee that splits it to supply each of my two rear HCV's. While passing through the base plate there are drilled passages to each of the "raise" solenoids.
So, Richard, you are right without me being wrong. The advantage of knowing that the plumbing is arranged as mine is is that by turning off the ball valve supplying the suspension system and watching the pressure gauge on the rear 6-pack supply you can determine if a leak is in the suspension system or some other system which would be shown by the rate of pressure drop on the dash "supply" gauge.
As someone at Newell told me, I've spent way too much time under the coach.