c210pa18 Posted May 23, 2023 Share Posted May 23, 2023 I am trying to understand how the tag axle is supposed to work and what the problem that I have really is. It is not working as it did before I changed the PPVs. I am sure that is used to lift the tag tire clear off the ground when you selected TAG UP on the switch. It does not now. It does take the pressure off, the pressure reading at the tag down pressure regulator in the driver's side engine bay goes down to zero. In this configuration rear tank pressure goes down to about 65 but the compressor will not bring it back up (front tank pressure strays up). If you use the brakes the rear tank pressure will go way down and not come back up, the front tank pressure still stays up. Now if you select TAG DOWN everything goes back to normal pressure builds back as it should. This does seem to be related to the problem I asked about in the thread a few days ago "Another Air system problem". I changed the air governor and thought I had that problem solved but I didn't realize that what actually solved that problem might have been that I had selected TAG Down. Link to comment Share on other sites More sharing options...
96 EVO Posted May 23, 2023 Share Posted May 23, 2023 Sounds like you have a bad leak in that system (maybe blown lifting bag). It shouldn't use that much air! Link to comment Share on other sites More sharing options...
Ivan K Posted May 23, 2023 Share Posted May 23, 2023 As Ben says, I would also think you might hear this sort of a leak? Lifting air is going through a Mac valve (below the gauge in my case) it could be leaking or there is a leak at the output line that splits to lifting chambers that are identical to brake canisters. Link to comment Share on other sites More sharing options...
96 EVO Posted May 23, 2023 Share Posted May 23, 2023 Right! Forgot they were chambers rather than bags. Link to comment Share on other sites More sharing options...
c210pa18 Posted May 23, 2023 Author Share Posted May 23, 2023 Ivan and Ben, I just got out from under the Coach trying to see how the lift works. I have been looking for lift airbags and found none but did find the Brake Canisters but was not so sure that they are what I was looking for. They must be as they are at the end of a lever that has chains on the other end that must be what lifts the axle. So I suppose those chambers have a diaphragm in them that could fail, is that true? I'm trying to "keep it simple" I find that often the failure has something to do with something that was just worked on so I'm thinking what did I do when I changed the PPV valves that caused this? I can't hear a leak as the engine is running so loud. Maybe I'll try shop air at that front fitting and see what I can find. Link to comment Share on other sites More sharing options...
96 EVO Posted May 23, 2023 Share Posted May 23, 2023 3 minutes ago, c210pa18 said: I have been looking for lift airbags and found none but did find the Brake Canisters but was not so sure that they are what I was looking for. Sorry Gerald! Brain fart 😔! Link to comment Share on other sites More sharing options...
Ivan K Posted May 23, 2023 Share Posted May 23, 2023 Yes, shop are with a drier is what I use too. If a diaphragm is bad, it is like $6 plus labor Link to comment Share on other sites More sharing options...
c210pa18 Posted May 23, 2023 Author Share Posted May 23, 2023 There is lots of air coming from the vent holes in the Canisters on the curb side unit. So I would guess that the diaphragm on that one is gone. Are these common Brake Canisters? Is there somewhere to find a part number? I'll go to work removing that canister. Link to comment Share on other sites More sharing options...
96 EVO Posted May 23, 2023 Share Posted May 23, 2023 I'll defer to Ivan who has possibly worked on his, but I think they are 30's. Link to comment Share on other sites More sharing options...
Ivan K Posted May 23, 2023 Share Posted May 23, 2023 I agree that 30 would be typical but there will be a number on the canister once you get to it. I did not have to work on mine, yet Link to comment Share on other sites More sharing options...
c210pa18 Posted May 23, 2023 Author Share Posted May 23, 2023 Got it off, Yes it is a 30 Thanks 1 Link to comment Share on other sites More sharing options...
Solution c210pa18 Posted May 23, 2023 Author Solution Share Posted May 23, 2023 So to report in. The problem was the diaphragm in the curbside Brake Canister was leaking, actually not perforated but the diaphragm flange that gets pinched in between the canister halves went bad and lost its seal. This is the Canister that they use to lift the TAG AXLE. It is a Type 30 short stroke. There are two, a short stroke which is a 2.5-inch stroke, and a long stroke which is a 3-inch stroke. Actually on this chassis at least it would not matter either would work as you can adjust the lift height by changing the links on the lift chain. So thanks for the help which got me to the correct part to replace. And actually, this was the main problem with the other issue I had in the "another air system problem" thread. I think I had a couple of issues there. I'll do some more testing tomorrow but it appears to be working 100% now. 4 Link to comment Share on other sites More sharing options...
96 EVO Posted May 24, 2023 Share Posted May 24, 2023 Good to hear! You certainly got right on that! Link to comment Share on other sites More sharing options...
TommyL Posted September 19, 2023 Share Posted September 19, 2023 Have several tight turns at home base ,so I do use the tag lift ( 08 camelot 43’ tag ). Wife is always my outside eyes in tight places, so she hears the new noises first. Air leak when you lifted the tag ! Still lifts tag , but a lot of air leaking around canister clamp, little if any out of small holes in can . Nearly impossible to get to and non adjustable cables, need to get the right stroke. OR since I can see the clamp maybe reseat the diaphragm. Not sure what it looks like inside. How about it c210pa18(Gerald) or Ivan , Ben or anyone who will share their experiences. Tommy and Cheri 08 camelot tag Link to comment Share on other sites More sharing options...
96 EVO Posted September 19, 2023 Share Posted September 19, 2023 I haven't been into one either. I would imagine Youtube would have several video's describing the repair. Link to comment Share on other sites More sharing options...
Ivan K Posted September 19, 2023 Share Posted September 19, 2023 I also could not possibly know what stroke is on yours, you could measure it but to avoid the trouble of doing so under the rig, I would just get both 2.5 and 3" stroke diaphragms before getting under and replace same for same. These are like $5 and the extra one could possibly eventually be used on a brake can, or whatever. I doubt tightening the clamp will help, should already be tight and repositioning the pancake takes same effort as replacing it. The clamp is the only thing holding it together. Gerald's was a Type 30 so good chance yours is the same but you can measure it if you dont see a marking on it. I never really looked at mine close, did not have to. Link to comment Share on other sites More sharing options...
TommyL Posted September 19, 2023 Share Posted September 19, 2023 Thanks Ivan and Ben , only leaks when raised so no hurry. Just hoping for an easier R&R for a not so accessible repair. Light rain now , will roll around under it more later. 08 camelot Link to comment Share on other sites More sharing options...
Ivan K Posted September 19, 2023 Share Posted September 19, 2023 I just started looking for my own mystery leak and had the coach fully aired up manually as far as it went. The tag lift canister is pretty accessible over the tag tire. The clamp bolt is on the inside side of it but reachable with a ratchet and short extension. May not be that much of a problem if yours is similar. Link to comment Share on other sites More sharing options...
TommyL Posted September 22, 2023 Share Posted September 22, 2023 Update, tag axel canister leak . 08 camelot tag . What a PIA to get to, Ivan ours was not even visible from the outside. 18” of extensions on 1/2 impac , removed 2 nuts from can , reaching up from under MH . Then hang upside down in engine hatch to remove eye bolt. That was the easy part. Monaco left O extra clearance between floor and canister. 2hrs of prying mostly by feel, it’s out of the bolt holes. d*** ,can’t get it out, got to move air tube from CAC. Now we’re on the work bench, time to disassemble 2min. New diaphragm 3 $ . Time to reassemble,9min. Reinstall 2 hrs. All good no leaky. Cocktail time. PS diaphragm size #30 21/2” stroke . 08 camelot tag 2 Link to comment Share on other sites More sharing options...
Ivan K Posted September 22, 2023 Share Posted September 22, 2023 Wow, sounds painful. Congrats on getting it done! And thanks for the size info. Link to comment Share on other sites More sharing options...
TommyL Posted September 22, 2023 Share Posted September 22, 2023 Hope the passenger side doesn’t blow, there’s a 6” bundle of wires, hoses, etc. over the top . If I were smart enough to know the brake can sizes, would buy extras. Fleetpride truck parts,3.00$ sure price will double soon. Tommy 08 camelot tag Link to comment Share on other sites More sharing options...
96 EVO Posted September 22, 2023 Share Posted September 22, 2023 5 minutes ago, TommyL said: Hope the passenger side doesn’t blow, there’s a 6” bundle of wires, hoses, etc. over the top . I was under there greasing yesterday, looked up at that mess and thought, "That wouldn't be fun !" Link to comment Share on other sites More sharing options...
TommyL Posted September 22, 2023 Share Posted September 22, 2023 My chest is so sore from hanging up side down in the engine hatch you can’t touch it with a powder puff. Also when upside down the bags under your eyes hang down blocking half your view. Getting old sucks, but it’s still better to be seen than viewed. Tommy &Cheri 08 camelot 1 Link to comment Share on other sites More sharing options...
Ivan K Posted September 22, 2023 Share Posted September 22, 2023 I guess I should consider myself lucky the way my access looks. I would just open it up in place. Considering that you are the second one in a short time to have this leak, I'll be getting spare pancakes now too and bet on a 2 1/2" stroke. And I feel your pain, literally. I resealed all 12 6pack valves in the rear yesterday and live on Aleve today. Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted September 22, 2023 Share Posted September 22, 2023 Tommy, that's hilarious and I thought it was just me Link to comment Share on other sites More sharing options...
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