Air Bag Leak

[JDHarrin]

Today was tire day. We bought this Aspect 28B three weeks ago. The seller told me he just brought it back from the service center to fix a few minor issues and that all was good. I didn't have an accurate tire gauge but he assured me they were fully checked by the service team. I brought it home and checked the tires today while trying to install the TST 507 TPMS sensors. Nearly all the tires were 20-25 lbs under-inflated. By the way, that Tireminder gauge, although expensive, sure is nice.



Anyway, I went to the water cooler to check the air bag pressure and they were dead flat. I put 70 lbs in the left and watched the RV rise up, then started on the right air bag. By the time it was up to 70, I checked the left again, and it was already down to 56. I sat quietly and could hear the air leaking from the suspension system.


So my question is, what's the fix? Can you patch these air bags? Do they need replacement? I need to make a short list of things needing fixed because the seller said he'd fix anything that was wrong with it. He's already on the hook for replacing the propane tank (it had a frozen on-off valve). Looking for suggestions. Thanks...


JD

[ziaptrn]

Hi and as a friend would say "Welcome to the Asylum!"
The air bags will need to be replaced if it is the bags themselves that are leaking. It could also be a leaky air line or fitting where they travel to or attach to the bags. The best way that I know of to determine this is to mix some water with dishwashing liquid in a spray bottle, crawl underneath with safety glasses on (that spray goes everywhere with a penchant for the face and eyes), and spray spray spray everywhere you can find. Put a good amount on until it drips, and any leaks will be revealed by bubbles. If it's the bag, then you will see bubbles there. The leaks are often accompanied by a sizzling sound.
If you can't find any bubbles and you have sprayed down every line, hose, joint, and fitting .... then the bags themselves are likely to blame.

I couldn't see what year your Aspect is, so hard to say about longevity. Some seem to dry rot more quickly than others, and some last the life of the rig. That said, I've never heard of patching them or anyone who offers to patch.

Here is a link to replacement airbags for the Ford E450 chassis. The airbags are the same across a wide number of years. I have no affiliation with SDTruckSprings, but have purchased from them before and this will at least give you a ball-park figure or starting point for the cost of repair materials, excluding labor, should the bags require replacement. Labor and per-hour rates vary widely across the US; I've seen everything from 275.00 per hour to 100.00 per hour or less. You'd do well to contact a shop that does truck work and get an estimate. No need for an RV-specific shop but no reason not to go to a reliable RV repair either; the air bags are part of the Ford truck chassis underneath the motorhome and should be serviceable by any truck repair shop.

https://www.sdtrucksprings.com/fires...2017-ford-e450

If it's just a fitting (and they do leak....ask how I know) it's a matter of finding the proper part number from either Ford or Winnebago, and replacing. Most of them screw/unscrew rather straightforward. Repairs are usually much easier than locating the leaks, which can be maddening.

Best of luck....
John

[JDHarrin]

Appreciate the background on all this. I'll try to get under the RV to determine just what's leaking. I just assumed it would be the air bags. With this RV being 10 years old, if it is the air bag leaking, I assume it'd be better to change both at the same time due to age. Does that sound right? Looking at the link you posted, would I need all the surrounding hardware as well, or just the air bag itself? I've found the air bag standalone for $137 - you just need to swap out the mounting hardware from the old to the new bag (again, an assumption on my part)... :-)

[ziaptrn]

I apologize that I didn't screen the link more closely. You should need to replace the airbag only and not the other parts....so you are correct...137.00 each plus labor.
I'd probably do both while under there....less expensive to do both than to come back and do a second later unless there was some sort of trauma to one that was relatively new. If age is the issue ... Then do both.
But check the fittings and lines first. They do leak and the bags may be fine. Some folks have bags that fail after 20 years.....so you are only halfway there. At the same time...if driven in poor road conditions and exposed to a lot of salt etc. They may need changing sooner.
As always .. ask questions and most all of us are happy to help you NOT make the same mistakes that we did. You'll make your own....LOL.
John

[JDHarrin]

Okay, I checked the air bag pressure today and even though I inflated both to 70 lbs (the manual says 0-100 PSI), they both had 51 lbs in them. So now I'm not sure there's a leak or they were just self-adjusting to this specific pressure. I plan to get under it and do a leak check early next week but for now, they seem to be holding at 51 lbs each. Crazy...