Doug and Nicki Posted May 17, 2022 Share Posted May 17, 2022 (edited) I have a 2008 Monaco Dynasty that is 45 feet with an ISM500. Not sure whether that matters. I am getting quite an air leak from the device shown in the pictures. Can anyone educate me on what this is and whether it is repairable or should be replaced? If it needs replaced, where do I go to get it and what is it called? I can’t easily see any writing on it, because it is quite a way above me. It is located behind the tag axle to the driver side of the engine and slightly in front of the engine. You can see the bubbles. Edited May 18, 2022 by Doug and Nicki Link to comment Share on other sites More sharing options...
Romeo84 Posted May 18, 2022 Share Posted May 18, 2022 Definitely not your governor unless it's connected to your air compressor on your motor. Looks to me like the service break discharge port. I just walked by this poster maybe it can help you. Haven't had a chance to look it over. Link to comment Share on other sites More sharing options...
RichardA Posted May 18, 2022 Share Posted May 18, 2022 Foot Brake treadle valve possibly ? Link to comment Share on other sites More sharing options...
Romeo84 Posted May 18, 2022 Share Posted May 18, 2022 Yeah some kind of discharge valve maybe parking break discharge valve Link to comment Share on other sites More sharing options...
Jdw12345 Posted May 18, 2022 Share Posted May 18, 2022 Looks like the air dryer to me…….. Link to comment Share on other sites More sharing options...
Tom Cherry Posted May 18, 2022 Share Posted May 18, 2022 1 hour ago, Jdw12345 said: Looks like the air dryer to me…….. I don't think so. I am ASSUMING (DANGEROUS) that Monaco used a Wabco Air Dryer assembly on most of their motor homes. That is usually located in the engine compartment and has a large filter (think oil filter design). The unit in the picture has no filter, or one that I can see and it would not be logical to put an air dryer behind the tag axle. BEST ADVICE... Use an inspection camera and your phone... or drain the air tanks and take it off. Otherwise, carry it to an OTR truck repair shop that can do DOT brake inspections. They will quickly tell you what it is and will replace it. As an aside, my Wabco started to leak a few years ago. I sprayed most of the major components with a soapy water and found that the Wabco was leaking on the front and back. The kits for both sides totaled over $200 plus the labor from my shop. I just bought a new one, which came with a new filter and had them replace it. Kits for air devices can be found....but the cost of disassembly and rebuild, if you don't have the skill set...or don't want to, typically are MORE than a new component... Let us know what it is after you identify it. Link to comment Share on other sites More sharing options...
staffcurtis Posted May 18, 2022 Share Posted May 18, 2022 It is the air dryer. If air is leaking from it either the valve is dirty and won’t close or something is leaking air causing it to stay open. It is probably the latter. Link to comment Share on other sites More sharing options...
Ivan K Posted May 18, 2022 Share Posted May 18, 2022 Link to comment Share on other sites More sharing options...
Doug and Nicki Posted May 18, 2022 Author Share Posted May 18, 2022 (edited) On 5/17/2022 at 11:07 PM, Tom Cherry said: I don't think so. I am ASSUMING (DANGEROUS) that Monaco used a Wabco Air Dryer assembly on most of their motor homes. That is usually located in the engine compartment and has a large filter (think oil filter design). The unit in the picture has no filter, or one that I can see and it would not be logical to put an air dryer behind the tag axle. BEST ADVICE... Use an inspection camera and your phone... or drain the air tanks and take it off. Otherwise, carry it to an OTR truck repair shop that can do DOT brake inspections. They will quickly tell you what it is and will replace it. As an aside, my Wabco started to leak a few years ago. I sprayed most of the major components with a soapy water and found that the Wabco was leaking on the front and back. The kits for both sides totaled over $200 plus the labor from my shop. I just bought a new one, which came with a new filter and had them replace it. Kits for air devices can be found....but the cost of disassembly and rebuild, if you don't have the skill set...or don't want to, typically are MORE than a new component... Let us know what it is after you On 5/17/2022 at 11:07 PM, Tom Cherry said: I don't think so. I am ASSUMING (DANGEROUS) that Monaco used a Wabco Air Dryer assembly on most of their motor homes. That is usually located in the engine compartment and has a large filter (think oil filter design). The unit in the picture has no filter, or one that I can see and it would not be logical to put an air dryer behind the tag axle. BEST ADVICE... Use an inspection camera and your phone... or drain the air tanks and take it off. Otherwise, carry it to an OTR truck repair shop that can do DOT brake inspections. They will quickly tell you what it is and will replace it. As an aside, my Wabco started to leak a few years ago. I sprayed most of the major components with a soapy water and found that the Wabco was leaking on the front and back. The kits for both sides totaled over $200 plus the labor from my shop. I just bought a new one, which came with a new filter and had them replace it. Kits for air devices can be found....but the cost of disassembly and rebuild, if you don't have the skill set...or don't want to, typically are MORE than a new component... Let us know what it is after you identify it. The air dryer is separate and is located a couple feet behind this part. Edited May 20, 2022 by Doug and Nicki Link to comment Share on other sites More sharing options...
Doug and Nicki Posted May 18, 2022 Author Share Posted May 18, 2022 (edited) I had time to crawl back under the RV today and get a better look at things. This is, in fact, the air dryer. I have an appointment Monday to have it replaced. I was absolutely wrong thinking this is something else. Chalk it up to a rookie error. Thanks to everyone for the input. Ivan, thanks for th picture and your insistence about what it is. Edited May 20, 2022 by Doug and Nicki Link to comment Share on other sites More sharing options...
Hypoxia Posted May 18, 2022 Share Posted May 18, 2022 Hard to see but resembles the ABS modulator valve Link to comment Share on other sites More sharing options...
Ivan K Posted May 18, 2022 Share Posted May 18, 2022 If you look at the picture I posted above, it is an exact match to yours. And mine is also just behind the tag, inside of the rail. A dryer. 1 Link to comment Share on other sites More sharing options...
96 EVO Posted May 18, 2022 Share Posted May 18, 2022 (edited) Believe that's the turbo saver valve on a Meritor Wabco system saver 1200 air dryer thats leaking. I can just see a bit of the spin-on desicant filter on your middle photo. Edited May 18, 2022 by 96 EVO Link to comment Share on other sites More sharing options...
WayneC Posted May 18, 2022 Share Posted May 18, 2022 Remember the dangers of being under the coach ,I would call a tractor trailer shop,make an appointment/send them a picture prior and have them change it out, I have replaced one of these and I think I paid $200 cnd. Wayne 1999 Signature ceaser Link to comment Share on other sites More sharing options...
Oldgoat Posted May 18, 2022 Share Posted May 18, 2022 Could be a moisture ejection valve. It will pop off every so often as the engine is running. Dumps moisture in the air brake system. Link to comment Share on other sites More sharing options...
96 EVO Posted May 18, 2022 Share Posted May 18, 2022 39 minutes ago, Oldgoat said: Could be a moisture ejection valve. It will pop off every so often as the engine is running. Dumps moisture in the air brake system. Yeah, that would be the air dryer. Link to comment Share on other sites More sharing options...
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