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Old 09-29-2020, 04:34 PM   #1
04 Winne Ult Advantage
Join Date: Mar 2019
Posts: 15
Air Brakes Locking Up-Help

I have a 2004 Winnebago Ultimate Advantage. On my way to Tahoe from Sacramento I stopped to take in the view. When I go back on the road I noticed that the RV was acting strange and it felt like the brake might be binding Or partly still in park, if that’s the right word. I went in reverse and hit the brakes and it appeared to clear up so I drove the rest of the way to our campsite . After registering I got back in the RV and on my way to the campsite it was binding again. Does anyone know why this would happen and any suggestions for repair? I also noticed that the air dump button doesn’t seem to work either. Related?

Would really appreciate any help.
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Old 09-29-2020, 08:33 PM   #2
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Just a guess, but it sounds like you have a leak in the airlines to one of your the "3030can" that actuates the brake OR you have a internal tear in your brake diaphragm and I'm guessing the latter.

* What does your tank air pressure gauge(s) read? ...Does it change when your air brake problems appear?

===> This is the best advice I can give you if you are not a mechanic===>

My Hartford insurance will reimburse me for Emergency Roadside Assistance LABOR (only). So I recommend you call your insurance company tell/ask them: I need a mobile mechanic. I cannot drive my RV. And if I call a local Diesel Repair Shop to send a mobile mechanic, will you reimburse me for labor?

Just for grins, if you want to know how to service your 3030CAN you can watch this video:

Note: Repairing a "Can" is easier than replacing one, but if your insurance covers the labor then I would ask your mobile mechanic to bring 2 cans with him and replace them both!

...If your insurance does NOT cover labor, and if you are CAPABLE of doing this repair, then by all means do a "half-can" repair or just replace the rubber diaphragm inside you existing can.

And for all the rest of use, this sort of thing is something you need to be aware of when you are driving a 15+ year old RV, because the diaphragm can not be inspected from the outside. ...And then one day: "Boom" you are stuck. So it pays to have a backup plan or at least know what to do.

One might go so far as to say, it makes sense to carry at least 1 or 2 rubber diaphragms (for your 3030can) with you since they are so cheap.

Please keep us posted. And let us know why your air brakes failed?
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Old 09-30-2020, 12:45 PM   #3
04 Winne Ult Advantage
Join Date: Mar 2019
Posts: 15
Hi, I appreciate your response. When sitting my gauges are at 26lbs. I started my engine and the gauges went up to around 87 on both. They usually go to 125lbs but I believe itís not going all the way because my jacks are still down. I went under the RV and found the air cans and looked over the hoses. I donít see anything wrong but that may not mean anything. I could probably do the repair you suggested but I am not sure if that is the problem.
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Old 10-04-2020, 06:16 PM   #4
04 Winne Ult Advantage
Join Date: Mar 2019
Posts: 15
My passenger side air bag developed a leak. Ordered a new one and will try to replace on Wednesday.
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Old 10-04-2020, 11:52 PM   #5
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Thanks for the update. And if possible, please take pictures of your repair if you do it yourself, so the rest of us know how you fixed your 3030 Cans.


* Are you going to replace both of them or just 1?

* Are you going to replace the whole thing or just the 1/2-Can as mentioned in the video?

* ...Or maybe you are going to just just the diaphragm rubber inside?

Now that we have a number of quality diesel RVs crossing over the 100,000 mile mark and 15+ years of service, do you think it's wise for owners to carry 2 of those cheap 3030-rubber-diaphragms as a back up... for in field repair like the video shows one can do without any specialty tools?

Note: The video above echoes this point: Repairing the 3030-Can-Diaphragm is a lot easier than changing the entire can. This is has to do with "cutting" the rod to fit in your application. TBD

Good luck!
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Old 10-05-2020, 11:16 AM   #6
04 Winne Ult Advantage
Join Date: Mar 2019
Posts: 15
Well it wasn’t the can it was a leak in my air bag. So I ordered a new air bag and I will attempt to take some pictures when I replace it. When it comes to the can I have had no problems yet but having at least one of those rubber membranes would be a good idea.
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Old 10-08-2020, 10:37 AM   #7
04 Winne Ult Advantage
Join Date: Mar 2019
Posts: 15
Well I received the new air bag at the campground. I used the RV jacks to raise the passenger side to remove the old bag. There was one bolt on the bottom and one on the top all accessible. Removed the nuts and unscrewed the fitting for the air line. It was a little hard unplugging the line but I was able to use vice grips on the opposite side of the fitting and pulled it apart. After that, it was easy to remove. I removed the air line fitting from the old bag and put it on the new one. Put some pipe threading tape on end of fitting before inserting. Placed new bag into opening and attached top bolt first then lower bolt. Secured air line and used silicone grease to get it started. Lowered jacks and done. Took about 1 hour total. Will do other side soon.
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Old 10-09-2020, 09:08 AM   #8
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Join Date: Jul 2020
Posts: 165
Remember Air Can 101 from larger trucks. When you push the button and dump the air cans; the removal of compressed air sets the spring brakes. A nice safety feature if you lose air, but then you are set locked in place. On trucks, at least, a T shaped bolt can be put in the air can, to manually pull off the spring, so the unit can be towed. Also, the air cans actuate a mechanical cam action, which due to cam wear or adjustment issues can cause locking of brake shoes or other brake function issues.
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Old 10-09-2020, 11:30 PM   #9
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Has anyone replaced just the rubber diaphragm inside the 1/2 can like the video shows?

I googled this part and it looks like Napa and even O'Reilly's carries it for only $6 each.

If so, it sounds like it would not be a bad idea to carry 2 of these rubber diaphragms for a back up if you have 15+ year old Diesel Pusher.

...I still would like to see a picture of a rotted-out rubber diaphragm if you have one?
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brake, brakes

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