I thought that I had seen a step by step tutorial on how to do this and problems faced/overcome, but my search hasn't been fruitful.? My 2003 IB just started giving problems closing completely. I have tried backflushing the area/seals, to no avail. I believe that it is time to replace the valves. As I recall there is an issue with there not being quite enough room to remove the assembly.? I would appreciate any help from someone that has had experience with this repair. Thanks. (PS I won't be home to do this for another 2 weeks.)
The Lazy Daze Companion: Dump Valves (https://lazydazearticles.blogspot.com/search/label/Dump%20Valves)
Thanks Joan, but the dump valves on the 30’ IB are different than the other models. They come together into a common outlet which causes some difficulties with spacing, as I recall.
Easier way to replace a dump valve - Part 2 (https://www.lazydazeowners.com/index.php?topic=28106.msg154481#msg154481)
Easier way to replace gray water dump valve... (https://www.lazydazeowners.com/index.php?topic=28065.msg154145#msg154145)
Thanks, Chris; that should help Bob! Maybe the posts for the 30’ dump valve changes could be added to the article in the Companion?
Be grateful for what you've got, guys. :-) My Airstream has its dump valves joined together under the middle of the body--hidden inside the aluminum "belly pan," which is riveted in place (!). They're worked by long rods extending out to the edge of the trailer. To change a valve, you'd have to drill out all the belly pan rivets, remove the pan, replace the valve, and re-rivet the pan. Whoever designed this apparently thought that dump valves never clog, never jam, and never need replacing. Yeah, right.
So after about a year of use, I had the same problem as Bob: the black tank's valve wouldn't close completely, and it slowly leaked... and thus when I took off the cap, nasty-smelling liquid splashed out. I had that valve replaced under warranty, but while they were at it, I had them cut a rectangular access hatch, secured with screws, under those valves.
Now at least I could get to them... but I'd have to lie on my back under the middle of the trailer to do it. So a year later when the black tank's valve again refused to close fully, I just stuck a secondary gate valve (https://www.amazon.com/gp/product/B000BGHYJS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) on the outside of the sewer fitting. Yes, it's a kluge, but I just didn't feel like changing a black tank valve while lying on my back with the dripping pipes right above my face!