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Air leak repair
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It has been suggested as a last resort, but everyone should recognize it should come from a supply that does not contain refrigerant oils that may not be compatible with the various gaskets and seals.
The four common leak detection methods are listen with your ears, listen with a stethoscope, use soapy liquid to look for bubbles, or use an ultrasonic leak detector. The less common but 100% effective is Hector’s Texas Bubbler which can test any system, circuit or device and spot leaks that are so small you can see the leak one bubble at a time.
There is no silver bullet and it takes a huge amount of time and patience. Once a coach is leak free maintianing that condition is easier than getting there.
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Look what showed up with soapy water…
At the bus barn today in generator bay. Just doing pre-trip inspection finding the pressure gauge read out on zero. Looking at the generator mini air bags no problem there.
Did a tap with my finger and pointer pops up 24 psi. I track down the mist sprayer and here is what showed up.
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Do something nice for Tom and he’s likely to fix you up with one of these:
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The valve above is a SMC manifold air distribution from the main feeder 3/8 inch line located in the rear of my bus. The 5 ports 1/4 inch then feed Marathon dialed psi regulators aux systems such as toilet, air doors, etc. When hit with the ultrasonic leak detector the reading was full max. positive air leak from the spaces in-between the double ports. It was a mini bubble machine with soapy water. The part was not available from my Eagle air parts supply here in KC. Eagle is a fluid component parts supply and custom mfg. order.
Very busy shop running two 8 Hr shifts 5 days a week. Brian, on the air side of Eagle disassembled the valve installed new o-rings. The double ports seems to be a good part adjustable when it’s building the bus. As time, heat, shake take their toll…not so good. A test with new Orings cured the leaks. With the remounting in the bus and charged the system we had some minor leakage.
Heat is the enemy for this part shrinking the O-rings over time
Brian located a 5 port manifold this afternoon which as you can see below completely eliminates the above shaft leaking problem. Mounting holes pre-drilled straight out or side mount.
For other Marathon owners you can check in your rear closet behind either a pull down panel or remove a drawer underneath your audio-video sets. If you have the plastic SMC manifold leaking give me a call for this repair/replacement part.
Manifold and fittings $24. for a permanent repair.
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This is just a personal observation that I am sure our leak detector guru Hector will echo.
Our coach fittings have slowly but surely changed over years from compression type to the push in type fittings. There is no doubt push in fittings are very easy to use and start out very reliable. A lot of the fittings on my coach are push in type that are swivel 90 degree fittings as Al shows and they are in a gang on a manifold. But as they age they leak.
In fact anything with rubber is going to become a problem over time. We see it in tires and air bags, Norgren valves and coolant hoses. So as we drive aging coaches chasing leaks is going to become a part of our duties. As I find leaks and where physically possible I am replacing leakers with compression fittings. If a compression fitting is installed properly it will be leak free forever.
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where does one get an ultrasonic leak detector?
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Mine is an Amprobe and doing an internet search you can likely find other brands and their distributors. I bet Amazon would list them.
A word of caution however……..if you are serious about chasing and repairing leaks recognize you need to be all over your coach. upstairs, in the various bays and beneath the coach. It is slow work, requires patience, and an understanding there is no silver bullet. You can work exclusively in the steer compartment for example and to be assured you have found all leaks that can be repaired in that area you will need all types of leak detection from soapy water to a stethoscope to an ultrasonic leak detector to a bubbler such as Hector advocates. Each method has its advantages, and even with all the tools available for leak detection you still have to know how the pneumatic system works to a certain extent so you know what you are being told by the leak detection devices..
Don’t let my apparently negative comments dissuade you. They are not meant to do that, but to merely help you understand an ultrasonic leak detector is but one tool, has limited benefits, and that once you become a leak detective you will also become an expert on the coach (and house) pneumatic systems.
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Spoke to Jon and Tom about the purchase of the ultrasonic leak detector. Each have a different type. Looking on e-bay there are many choices but my concern was returning it and who knows if it works correctly once you get it.
I landed on W.W. Grainger Co. and there complete assortment of testers are pictured on line. Narrowed down choices to two. Both were at Grainger in two days, there was no problem trying each one in the store.
My choice was there Bacharach model 28-2000, features included head set, light scale indicator meter, extension tube attachment, sensitivity adjustment, 30 day return.
It works without spraying soapy water around electric components near lines. Getting a hit with soapy water will confirm the leak. Found that if the drop light is real close to tester can produce false readings. This tester picks up leaks we can not hear. You think then it’s a minor leak but putting about a half dozen finds resealed will make a difference.
Installed the new air manifold today with new lines. No leaks detected .
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Steelman has the most choices. http://www.steelmantools.com/Diagnostic-Tools.htm. Lots of retailers including Amazon and Sears.
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Still looking for the time to visit Di. Oh, and Jon too. Depends on some business things. Pricing them online $600 is pretty pricey without some more background.
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Go for the Steelman Bonz, under a hundred bucks and has worked great for Brian and myself. Oh, I forgot, you have a Liberty, so the king daddy leak detector is in your future:)
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Tom What is the model # of your unit. Thanks Rick
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’tis true, Tom! 😉
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Don’t confuse an ultrasonic leak detector ($300?) with an electronic stethoscope. Two different devices with the ability to sense different types of leaks and noise levels.
http://www.testersandtools.com/Amprobe-ULD-300-Ultrasonic-Gas-Leak-Detector.php
That was just a quick look, and there may be better deals.
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Rick,
It’s this one: Steelman
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