Continuous air leak from air dryer purge valve

Is the aur dump valve you speak of constantly leaking located back on the frame between the two drive tandem? I just replaced that box as mine was constantly dumping air. Put a new one on and still same problem. Even though it's back on the frame I think the air dryer is the culprit. Just curious if that dump valve you mention is the same as mine.

 

Good job. I do this for a living, but I still like to see guys fix their own stuff.

 

Jesus ####s sake! $2000 for an air dryer? And those guys are still able to sleep at night?

Go to Truck Pro... I think I paid less than $200 for a single cartridge Meritor look-alike. It's been on there over a year and still working fine.

 

Sounds like you have air coming out the exhaust port of your relay valve. Clamp the emergency line off at each brake can, one by one. If the air stops coming out when you clamp a line off, change the offending can... the pancake is bad.

I'm kind of anal though, I'd do them all at once. If one is bad, the others are surely not far behind.

 

You are talking about the brake cans right? I figured I'd do all 4 in the back if one is bad lol. I'm anal like that too and as sure as I didn't another one would screw up.

On a similar issue, I have found that my primary tank is filling up with quite a bit of rusty water. I'm in the process of changing the air dryer cartridge but the one I took off has male threads and the one I bought has female threads. Have you seen them with male threads before?

 

Yes, the brake cans.

The one you took off has male threads because the pipe nipple came out with the cartridge. I've never replaced just that cartridge because the whole complete dryer was only a hundred bucks more.

 

Ended up changing the whole dryer. Keeping the extra filter for a back up. Also had to change the main compressor line running to the dryer. Everywhere was closed so I'll get that hose in the morning.

 

It’s been years since I’ve changed a cartridge, I usually just change the dryer on mine. However I do remember a while back I ran into One that had a “left hand” set up. It was weird as all get out. The cartridge screwed on left hand. Not sure if that helps and I know this is an old post but maybe someone else may find the info useful. Happy trucking and happy holidays fellas.

 

I'll be ###### if I'm not gonna be under my truck replacing the air dryer again. Was losing air pressure while bobtailing to pick up a load. Got about 2 miles from my house when I pulled over. Hasn't even been 6 months but I'm thinking the 0 to 10°F temps all week caused the housing to freeze as it's constantly dumping air. I changed filter but I think it's frozen underneath in the housing. Happy New Year's lol

 

My truck is a toterhome conversion. Because it doesn't move much (400 mile trips 3X/year in the summer then it sits), and knowing sitting is bad for anything, I have an alarm on my phone to remind me to start the engine and let it run for an hour each week. Sometimes I'm busy (or forget) and it runs 6 hours. I also try to take it around the block about once a month (a 5 mile loop) but I've not been religious about it so sometimes 3 months go by between 'trips'. Another thing I've not been religious about is pulling the release cable for each air tank (I do this maybe once a month but in future will set an alarm for this as well).

1. Is draining the tanks monthly enough, or should I do it weekly?

Anyway, the other day, I started the engine and it wouldn't build air pressure (but the ear splitting alarm in the cab was certainly doing it's job). I worked my way beneath it (fat guy, not easy) and it's exhausting air at what I suspect is a purge valve on the dryer body. Since lilillill mentioned a Wabco look-alike for $200 and my truck Cat-engine 2001 Freightliner Century (G23436) calls for a Bendix 800383 (single cartridge) and the best price I've found is $600. Meanwhile, I've also found this: REPLACES FOR BENDIX X800383 NEW AIR DRYER AD-IS ADIS EXTENDED PURGE STYLE 801266 6941577314517 | eBay

2. This seems to be a similarly priced Bendix look-alike - OK, or pony up six bills?

In the dryer photo, the leak's at the 50¢ size port on the bottom. I'm all ears, and many thanks for your advice in advance!
--
John

 

Ok so I have the same issue. Frigid temps come and my low air, and air dryer is froze up.
Here’s what the diagnosis was.
Bad oring in the air compressor. It throws out unusuall amounts of moisture into the air lines, causing air dryer to freeze.
Solution: replace the air compressor