black tank valve hard to operate

[Barry Parkof]

The black tank valve is hard to operate, and does not close all the way. It is about 1/4" shy of closing to where the clips will hold it in place. Also, the tank did not drain at first with the slinky, but with a Sani-con macerator, it seems to empty it. I am wondering if this is just a paper clog at the valve, or if the valve itself could be damaged. This is on a 2007 International model.
I tried backflushing from the grey tank, and flushed the system two times, but the valve still does not close entirely, and I am not conviced it drains freely.
Please help.
Thanks

[wasagachris]

Try backflushing with hot water if you can. Maybe that will loosen up the paper jam. I would keep trying to flush out the tank a few more times and see what happens. Some people also dump ice cubes down the toilet and go for a drive. the ice seems to break up any deposits of you know what.

[handn]

When knife valves get old and bulky, they should be replaced as the plastic is getting hard and wearing out. Often you will get minor leaking.
Both of mine are six years old and need replacing before they fail completely. I have been putting off that unpleasant task.

[thecatsandi]

Once you clear the blockage in the valve, pour a little vegetable oil down the toilet. The Grey gets lubed with body oils and oils from washing dishes.

[DaveFL]

Not closing by a quarter inch is also the way mine felt, when it leaked, took it apart and found the o ring had shifted. No amount of lubrication or flushing would have solved it. As a temp fix another valve can be installed just before the sewer connection that way you can open the cap without getting wet.

[seacur50]

I'm having the exact problem you describe. Just tried flushing the tank out and adding water with some laundry soap. I put the cap on and opened the black tank valve(it still works ok). Towed over a crooked road for 2 hours to slosh things around but no improvement.

[Barry Parkof]

We just left on a trip out West, and since the valve was not leaking, and replacing the rubber gasket involved dropping the tank cover, drilling rivets out for the gas line attachment clips, etc. I decided to go with what I had. I tried the vegetable oil and just today, when I emptied the tank, the valve operated very smoothly. Probably more smoothly then when I first purchased the Stream new 2 years ago. It also seemed to close completely. I will let everyone know how this works out, since we will be gone about 2 months. Perhaps the chemicals we use in the tank dry out the seals.