Well we just got back from our trip to the Buffalo River and I wanted to post an update to our solution for two leaky gate valves (one toilet valve, one tank valve) and a cracked black tank.
As a reminder, we have a '66 Overlander with a Thetford Porcelain toilet. The whole system needed to be fixed or replaced, and we concentrated on repair since we were short on time.
We tracked down a repair kit for the stainless backed thetford valves, and were able to replace the interior gasket on the dump valve. (Took the valve apart and inserted new rubber gasket inside.) We figured this was the most important valve to fix and could only find one kit.
Having previously bought the incorrect repair kit for an all plastic valve, we took one of the o-rings from it to re-seat the toilet valve back into the toilet assembly and merely lubricated the interior valve gasket with silicone as it looked to be in ok condition. This valve still leaks a tiny bit, but quite frankly the toilet bowl does not really need to hold water, so no worries. The leak goes straight into the black tank.
Now, the black tank we sealed with plastic epoxy (about four tubes worth) and it appears to be performing very well so far. When the time comes we will replace the tank with a new one but we were in a hurry to get on the road and the tank is in otherwise very very good condition. The dump valve here still leaks a bit also - I think this is because, even though we replaced the gasket, either the blade is too worn to give a good seal or - the entire assembly is a bit weak due to a couple of the corners where it mounts to the tank were broken. We patched these corners with metal plates before mounting but perhaps the valve just does not seal as well as before due to being a bit "loose".
The fix for that, since we were getting on the road, was quite easy. Found an expandable rubber drain plug at Lowe's, the kind you put in a floor drain and when you screw the wing nut tight on top, it flattens out making it fit snugly into the drain. The outlet from the tank is about 3" ID, bought a 2 1/2" (I think, the large one was too big I recall) plug that fits just GREAT and completely stops the tiny leak. We did have to buy two of the plugs - they have a metal top and bottom, and the top is too big to fit the outlet. The bottom metal plate though is just fine, so we replaced the top plate with a second bottom plate from the other plug. Used long needle nose pliers to tighten after putting the plug into the outlet just past where the grey water outlet joins it, so we could still use the portable grey tank. Held like a charm.
Now, before you think "eww gross...what happened when you opened that plug up?" - let me just say that we only used the toilet for #1 and no paper was allowed in the tank. (By the way Target sells a great stainless steel toilet paper roll holder with a lid that makes a dandy tiny trash can for an Airstream bathroom!!) After adding some tank treatment, and using water to flush, the end result was really nothing much more than water, and only a tiny bit came out when the trailer was level and the plug was removed. Worked for us, but on the way home we went to Colaw's RV salvage on I-44 in Missouri and found a whole bin full of assorted Thetford valves. While nearly all of them were labeled as T-1169 models, they all seemed slightly different but we did actually find a lone stainless one that looks nearly identical to ours and so I hope to replace the tank dump valve with that one and get rid of the plug. $25 pricing was awesome!
They also had a whole box full of the repair kits for stainless valves if anyone needs them. I almost bought a bunch but...we may be going back in July if anyone wants me to pick up some.
This is getting long winded, but hopefully those looking to keep their old toilets and tanks will find the info useful. If you think about it, there is little to go wrong with the old toilets - there are basically a bowl with a valve and it is the valve that generally is going to go bad - specifically the gasket but sometimes the whole valve. If you don't mind getting in there and replacing stuff, you may very well be able to keep your rig original.
I will try to post some more pics and part numbers, etc or feel free to ask any questions. We love our original toilet, and getting it back in, along with the repaired tank, was actually a snap. MUCH easier than getting everything out. It's not a perfect fix yet, but we are content for now and hopefully with the replacement valve we will be back at 99% condition for as long as the black tank holds up! I can't say how much I enjoyed being able to use the toity in our home away from home for the first time - those early morning trips to the pit toilets were not my favorite part of camping!!!
Oh yeah, we had a great trip and look for a post soon about the Buffalo River National Park - it's really not to be missed if you like canoeing!!