[Art]

Change them to compression fittings

[Tim]

It is a certainty that as coaches age, push in air fittings are going to start leaking.

It is also a certainty unless and until you methodically replace those fittings with compression fittings as normal maintenance takes place you will be chasing leaks.

Routine part replacement, such as air bags, Norgrens, brake chambers, house air fittings etc. will eventually fix a great deal of the air leaks, but there are so many potential leak sources it might take a concerted effort to find all the leaks.

The biggest leak will usually be the Benjamins disappearing from your wallet if you do not undertake to do the leak detection and fitting replacement yourself.

[Archived]

If you really want to do some of the work yourself…

First. Click here>>>Go to this Prevost Technical Manual page. Using your coach VIN, figure out which pneumatic diagram (PDF) is the appropriate for your coach, download it, and learn how to open the file.

Second. Study the drawing for a bit (zoom in for a better look). After a little while you will be able to correlate some of the things you see on your coach with the drawing. It looks like the picture you posted above is in the maintenance bay below the drivers seat…maybe.

Third. Make up some leak detector solution…Google it or use ¾ cup dish soap to a gallon of warm water. Don’t shake it up, stir gently. There are other ways to find leaks but this is a starting point.

Fourth. Air up the coach a spray away. Find some leaks???

Fifth. Learn how to disassemble, remove the plastic/nylon tubing from the push to connect fittings. If there is air pressure in the the fitting it will be much more difficult, if not impossible, to disassemble. Firmly push the tubing into the fitting then pushing and holding the movable ring (I sometimes use a 3/8 open end wrench for 3/8 tubing, a ¼ wrench for ¼ inch tubing, etc) toward the fitting and pull on the tubing. If all is right with the world the tubing will come out. If not try again.

Then the fun begins, Ideally, replacing the push-in fittings with compression fittings is the best course of action but sometimes you can buy some time by removing the tubing from the fitting, squarely cutting off about a quarter inch of the tubing and reinserting it into the fitting. You will have some that just won’t seal and the fitting will have to be replaced.

Air up check for leaks. Drain the air out and try to fix some leaks. Air up check for leaks again. Rinse and repeat. Some successes, some failures.

There is way more to it than just this, but this will get you started on some of the big leaks.

If you learn how some of the various subsystems (suspension, brakes, etc) work, you will get better at chasing down leaks.

Oh yea, if Jon says it is likely this or that device or part…I would start there!

Best of luck.

[glen]

Nice advice and informative. And yes, Jon is the man on leaks!

[Archived]

Thanks all for the advice and insight, this is going to be a real newby question but where and how do you drain the air system ?

[Thomas]

First, take some time to think about safety. We have multiple air systems so there is no single place to drain off air pressure. Depending on your conversion you might have more air tanks than those supplier by Prevost.

Support the entire chassis, Raise it all the way up via Level Low and support the chassis. You can deplete the air in the air bags (suspension) using level low.

You can deplete air in the brake systems by pumping the brakes.

You can deplete air in the accessory system by cracking a fitting or if you wish to get beneath the coach with the petcock on the bottom of the tank.

I do have a concern however that you approach your problem systematically rather than using a random scatter gun approach. And before you dive into the project spend time looking at the diagrams as suggested above and learn how to mentally separate the Prevost and converter systems.

Do not hesitate to ask questions. This is important.

Unrelated, for years I used any DOT certified compression fitting to replace push in fittings. This past year I found a Swagelok distributor a few miles from my house so when I replaced my Norgren valves I bought the Swagelok fittings for the first time and can say with conviction I have never had a better compression fitting and will only use them from now on. The difference in quality was amazing and the price seemed in line with others.

[Fred F.]

Thanks for the sage advice I have spent over 30 years in the oil and gas industry and one thing that has been pounded into my thick skull is safety… and sorry if I gave the impression that this was a “scatter gun” approach it will be done very methodically and with extreme caution as some of these air lines and valves look very brittle… thanks again for all the information extremely helpful!

Swagelock fittings are the best Oil and gas has been using them for years very durable and reliable

[Roy]

Hard to get to, but worth while is to replace the check valve coming from your Aux air compressor in the Gen bay Hush Box. Mounted to the top of the box on the inside toward the back on my Vantare. The hot air seems to cook those check valves. Boater Al has a post listing availability and part numbers in the archives.

[John]

Adding on to previous reply: Once you find the proper air diagram for your coach, download it to a thumb drive, take the thumb drive to a local Office Depot/Staples, and ask them to print it out poster size and then laminate it.

Now you will be able to read the small print on the diagram and use erasable markers to keep track of working on your leaks.

[Archived]

Jon,

Who is the Swagelok distributor here in Knoxville?

[glen]

Swagelok.

Exit 398, head north on Straw Plains and across from McDonalds is Brakebill Road. Go on Brakebill, left on Crosswood and between Travelodge and Red Roof Inn turn right onto Blakely Court. It’s hidden. For the almost 20 years we lived here I never knew it existed.

673-6610

[Archived]

or,

http://swagelok.com/en/catalog/fittings

[Andre & Kathy]

I wonder if Swagelok is a candidate to be an advertiser on the PC Forum and offer discounts to members and highlight the fittings we need for our coaches.

[Archived]

Look at their catalog and you will see compression fittings are a small part of their product offerings and I seriously doubt if every Prevost conversion was switched to those fittings their bottom line would be hardly impacted.

I did not consider their prices inconsistent with what the rest of the market charges, such as Grainger, Fastenal, NAPA, and other sources for DOT fittings.