[steve]

If you are watching your main and aux tanks lose pressure while driving and not touching your brakes, it could be the brake lines themselves. Scared the heck out of me as I knew I was losing air pretty fast while driving and would watch the gauge drop 20-30# in seconds, pressure up, and repeat the cycle. Prevost found a line running against the frame and it had worn a hole in the line. New air brake line and no more leaks.

[Art]

Did u replace push fittings with compression ? Temp affects pupuch fittings like crazy when cold.

[Chuck & Katrina]

If your dryer’s check valve or purge valve is bad that will cause that, primary and secondary tanks have check valves so they will not move but wet and aux will, how is the condition of your dryer? I had the same thing happen easy fix, I replaced my hole dryer it wad OEM I installed a new Bendix AD9 dryer my truck buddy said that what all the trash trucks use very tough and dependable.

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2000 Featherlite H3-45

2024 Jeep Grand Cherokee

Leesburg, FL

[Bill]

WOW, Thanks everybody for the great responses.

Jeff: Think I hear a leak back by the duals/tags. Just got home, will be putting the old girl up on ramps and crawling underneath with the shop air connected sometime in the coming week to check.

Bill: My brake tanks stay constant at 125 PSI while on the highway. Aux is the one cycling up and down 25-30 PSI every 5 minutes or so.

Steve: I have replaced about 90 percent of my push on fittings with compression fittings. Murphy’s law says my leak will probably end up being one of the 10 percent push on’s I didn’t replace.

Art:You may have something with the dryer. Backed the coach in the garage today when I got home. Shut it OFF, walked around and plugged in the power cord then all of a sudden the dryer sneezed. How the heck can the dryer sneeze when the engine has been off for 3-4 minutes? Did change the dryer filter about 10 months ago. I have the Bendix AD9 on the coach now.

Chuck

[Ed]

It was in the purge valve on the air dryer.
Zoom in and look at the 6 O’clock position on the purge valve. There is a small piece of O-ring lodged in the exhaust valve.
one of the internal O-rings dried up and pieces we’re breaking off and lodging in the discharge valve.
Rebuild kit resolved the issue.

Chuck

[Jeff]

Great news! Amazing how challenging locating the issue can be.