Air leak

wtmtnhiker wrote:
I have an air leak that I had asked about in a previous post.

For the sake of continuity and to avoid confusion, you really should just continue THAT thread with subsequent information and additional questions.

Why limit it to 75??? Yes you can do it.

No problem at all.

But, depending on where in the system you "back feed" it, there are check valves that should keep pressure from going back from that tank toward the dryer and compressor. So, it may not pressurize the leak site.

wtmtnhiker wrote:
I have an air leak that I had asked about in a previous post. To follow up would it hurt anything if I charged the air system with an external compressor while I tried to pin down the leak? Thinking I would keep the pressure to about 75 PSI or so. I have a convenient place to tap into.

wtmtnhiker,
As Brett stated, it won't hurt anything to "back pressure" your system. On our '04 Itasca Horizon 36GD with the C-7 330HP CAT, we have three places to feed air into the air system.

1. Above the generator, with gauge, to the left.
2. To the right of the generator, into a schrader valve on a small manifold
3. At the air dryer, on a schrader valve.

If the air system on ours is below 60 psi, and I attempt to put home air (normal home air pressure for my system is right at 140 psi) into the coach, at either of the up-front two points, the gauge will immediately go to 120 or 130 and, no air will enter the system.

But, if the residual air pressure in the coach is say, above 60 or more, and I install air in either of the two up front points, you can see the gauge start to climb and you can tell the entire air system is filling. But, my cut-off valve will not operate.


But, as stated, if my air pressure on the coach is at or below 60 psi, the only way the air system will accept air is if I go to the schrader valve on the air dryer. When I do it that way, the air system will accept the air and, when the pressure of around 120 is reached, my pop-off valve will let me know when the system is maxed out.

So, that's how my system works. Don't know if yours is the same or not. Good luck on finding your leak. I have one too and, it's been a bear to find it. Still haven't.
Scott

Depending upon the coach you might be able to locate a valve designed specifically for this purpose. You can air it up as high as the coach is designed to be aired up. Our coach airs up to 120# before the compressor cuts out and if yours is similar you can air it up to that point as well.

Yes, some air chucks have a check valve between the chuck and tank.

If you have a schematic of your air system, you could very quickly tell if backfeeding would work.

From a design standpoint to be able to be successfully towed by a large wrecker, there should be a place for the wrecker's air system to connect to the coach's air system to keep the suspension aired up while towing. If you call Monaco, THAT is the one that would probably work best.

I have used service truck air to get disabled semi's off of the road having them follow me slowly to a pull off with a hose between us.
Two things to ad, a spray bottle with dish soap and water works well for finding leaks.
Also, a child's hearing is much better than an adult.
If one is available to help it might make a difference.

Most times if you run the engine until the air dryer kicks off and you have full pressure, you can shut the engine off and you should have plenty of time to find a leak.
Just be careful about going under the coach as the air leaks down the coach can settle and you can be severely injured or worse. Make sure it it properly supported.

Thanks to all for the replies they were all very helpful. I was able to pin the leak down to the park brake push/pull valve itself. I got a number off the valve but have had no luck matching it with anything. I'm going to make another post asking for help locating this valve with the part number that I copied off the valve.

Update:
I had no luck trying to cross the number from the tag on the valve. Apparently Holiday Rambler put the sticker on the valve with a Wabco part number but it's not a Wabco valve and the number on the sticker doesn't come up on Wabco's site. Upon further inspection I found a part number embossed on the valve housing with the name Midland. I was able to take that info and find a new valve on Amazon which they call a Midland style KN20031. It's only 24.00 so likely be replacing it again sometime. Thanks to all for looking.