[Bryan]

Dean,

On the two Vantare’s that I have owned, one area to look at is the Generator air bags, and mainly around the regulators for the Gen bags. On both coaches, the regulators (one for the front bags, and one for the rear) were both leaking, and they are all push in fittings on them. Make sure and check the regulators themselves too. Also, the regulator in the steer compartment for the step slide and other items, is a known leak point.

Check the bags for the engine belts, and all lines, regualtors and fittings.

I’m sure Jon will jump in with more detail, but mainly get a spray bottle with soapy water, and start spraying. We have all been there, or will be!

You can also go to East Tennessee Luxury Coach, Jeff is very good at finding leaks.

[Glenn]

I’ve been to Houston with leaks a couple times. Also to Ft Worth a few trips. Head to Jeffs if you want it fixed. I haven’t been to Jeff’s but that’s where I will take mine next.

[Gerald]

I just had a coach that was driving me crazy trying to find the leak. I use ultrasound when possible, however on this coach it has a lot of electronic noise that makes it difficult to find using this….Soap found it leaking out the head of the aux compressor….

[Chas]

Dean,

All good information and each converter does things a little different. If your aux compressor can’t keep up, you should be able to hear the leak. If you have access to shop air, hook to your aux system and then you can listen for the leak without the compressor running. I use an electronic stethoscope as well as soapy water, sometimes it takes a combination of both.

This is more Marathon specific, but it will give you an idea of leak sorces:

Gen air bags

Gen air regulator

Aux compressor

Aux air Norgren drain

Floor slide

Floor slide regulator

ISRI air seat

Air seat regulator

Aux air dash gauge

Steering compartment fittings

Aux air tank

Marathon aux air tank and lines

Pocket doors

Pocket door regulators

Backup light door, rear top

Backup light door regulator

[Archived]

Jeff, That problem would not have happened or been evident if the coach had a functioning check valve downstream from the compressor. It needs one or it needs the one it has replaced.

[Tom]

Thanks everyone.

Looks like I have plenty of things to look at before we leave.

After all the good things I have been reading about Jeff’s place I would love to go there but he is the wrong direction and I am afraid it may be to cold to spend a few days there getting the work done this time of year. I do have some other things we are thinking about doing after we get back next summer and will definatly talk to Jeff about them.

There doesn’t seem to be any comments about Prevost Houston. Is that because they are so new or is my problem better handled by a place like Jeff’s that is more familiar with the converters side of things?

[Larry & Diane]

If your leaks are with the house portion of the conversion Prevost is the wrong place to take the leak for repairs.

[Archived]

Prevost Houston did a ton of work on our coach last year for the previous owner right before we bought the coach.

All of the work performed is still in good working order. The seller spent about $18,000 with them prior to me buying the coach. All items listed on the work orders are still working properly.

Some of it did seem expensive but again the work itself was up to par.

[Archived]

We are actually headed from Houston to AZ could anyone suggest a place that may be a better fit to look at this problem?

[Ronald]

Unless the air leaks are affecting your use of the coach it might be best to wait until you are ready to isolate them your self, or you are going to be near a shop that has a track record of doing this type of work efficiently.

Your aux air is used by the coach for the suspension, slide seals and belt tensioning among other things. The conversion part uses air for a variety of things such as the seat, dump valves, pocket doors, generator air bags, bed lift, etc.

If you have the key off and you lose air the chances are tipped towards the problem being with the conversion. If the leaks however make your aux air gauge cycle up and down it could be the suspension or other areas associated with the chassis. Someone skilled at isolating leaks has usually developed techniques to isolate them. What newer coaches are dealing with to an extent is the push in fittings age and begin to leak so you could have a single larger leak or multiple smaller leaks. One thing is known however. Fixing leaks is one of the quickest ways to accomplish wealth redistribution. The money flies out of your wallet never to be seen again.

A number of us have attacked leaks with a vengeance with satisfying results being the payoff to mind numbing patience checking every fitting and device.

Does your aux air gauge cycle often while driving? How often does it go up and down per minute or hour?

When parked do you need air for a slide seal, and if so, when the pressure goes down on the aux gauge are you holding slide seal pressure? How many air operated devices are in your house? Have you checked to determine if the aux compressor has a check valve downstream? How often does the aux compressor run? Are you drainng water from the air systems routinely?

[Larry & Diane]

Dean, if Jeff is too much the wrong direction and you’re comming from Appleton area, I would suggest Parliament in Clearwater, Fla. Our only experience with Prevo Dallas was an emergency tire R&R, but I wouldn’t use Prevo fo the converter side unless absolutely necessary. If you want more info on Parliament feel free to call me 941 779 5018 Geo.

[Corey]

Jon

I have not had a chance to drive it since i discovered the air leak. I am not sure if I need the air for the slide seals when parked so how could I check that? That is one of my concerns that my slide seals my leak water this winter while we are in AZ. I believe that the only air devices that I have is the step cover slide. I am not sure about a check valve downstream I will have to check that if it does what would that tell me? The aux compresser will run all the time but not keep up so I have shut it off until figured out. I have always been draining the aux system and not been getting much water when I do until this happened. The way I discovered this is the aux compresser was running non stop and when I drained the air lines there was a lot of oil in them and the compresser was down on oil and had gotten very hot. So hot in fact that the paint had bubbled up on part of the compresser so I hope that it is not dammaged. It seems to build air fine it just can not keep up with the leak.

The concern I have is that I will have issues this winter while we are in AZ if I don’t get this resolved.

[Glenn]

Based on my own experience when I went 100% after air leaks.

My number one item to replace is the check valve leading outbound from the AUX compressor. It should be on the list of items replaced on time in service. If you have a leak from AUX intake it’s the AUX check valve.

This check valve is easy to replace and cost under $20 available at Grainger. Several things are available through other venders if you wish to buy a custom made check valve.

I had own built with a suggested “cracking pressure” if your in the valve business this is a operating term. Suggested my custom valve be 5 psi cracking pressure. So 5psi cracking pressure (air) is needed from your air compressor to open the valve. Another change was the valve surface be coated or made with “viton”. This superior material is preferred as it will operated in heat/water conditions up to 400 degs.

Again heat and water are the enemy in check valves. Marathon installs there valves right out of the Thomas Compressor. Not the best location for a check valve but with a change out every 2 years you will be ahead of the leak game.

After my air leak adventure the Marathon AUX compressor ran once in 5 days when sitting at idle. Getting lots of other leaks fixed I spent around $1000. Another item is the air operated toilet. That story is complete book in itself and posted in the plumbing section.

Another item and near the top of the list is the brass wheel drain valve at the bottom of AUX reserve tank under driver. Get rid of it ASAP it’s leaking now or will shortly. Poor design, not a good choice as it has to be in nearly new condition to work properly, seating of valve is the issue. Replaced with a regular gate valve this style will not leak for years in service.

Check valve is the first piece of brass at 9 o’clock position from gray block.

Check valve removed above. Can be easily confused as a common pipe fitting. Usually stamped with an arrow showing direction flow. Be sure you check direction flow prior to install. If you get wrong you’ll be taking it apart again to reverse.

New reliable drain valve

Picture of wheel valve…..get rid of this valve…… the seal is the problem, just add water.

[Gerald]

Dean, you might want to also check the air bags on the Gen-set. Ours leaked down so fast that I shut off the Aux when parked and started it only if I needed the generator. The only other thing it was needed for when parked was the pocket doors which we really don’t use much. They caused the Aux to run rvery 10-12 min. Given the amount of oil though, Al might be on to something and you might very well have more than one problem. Geo.

[Archived]

I’ve got good news and bad news. The bad news you already know: You have a leak.

Here’s the good news. If the leak is so big your compressor cannot keep up with it you should have no problem isolating the leak. Tom is deaf and I’ll bet even he could hear one that big.

All kidding aside, start the coach and let the engine driven compressor air up the coach. When it is fully aired up shut it down and go outside and start listening. You should be able to hear it. It may take several tries as you try to get closer to the source of the leak, but at that rate something is literally blowing air out.

We can speculate all day long, but until you help with either saying what is leaking, or getting specific as to the location we probably cannot offer any good solid advice. Al did a great job of helping you understand how he installed his check valve, but keep in mind each converter has done things differently so locations and how the systems were plumbed are going to vary from one conversion to another.

Prevost has pneumatic diagrams available for reference if you want a better understanding of how they located components and where each line originates and goes. If you can gather that information from your converter that will help you in pin pointing the leak. Depending on what is leaking you may be able to disconnect the line and plug the supply side port until you can get to the exaclt leak location. But no matter what you can at least for the short term add a shut off valve once you know which air circuit is the issue.

I will not be so bold as George and suggest at this point you have multiple problems, but if you do, based on how fast air is leaking you still likely can hear the leaks. That is where the converter’s drawings are helpful because you will know if you can just plug the line and do without the device that is leaking, or if you have to make immediate repairs.