Liquid waste knife valve leaking (not the black tank)

[Geterdone]

I have an issure with knife valve on liquid waste tank leaking when shut off. The cable itself will not push all the way in, even after lubing the cable and some waste leaks into the down pipe. Does adding cooking oil or some tank lube work to free this...It is on a 2013 Lance model 1172.

thanks,

Steve

[Super_Dave]

I had a situation where after draining the tank and putting the cap back on immediately, the cap would fill up with residual water from the walls of the pipe. Everytime I took the cap off, water would spill all over me. Now I drive home with the cap off so that the pipe dries out and finishes draining.

[Joe417]

I use the twist on valves because I don't like surprises either but the valves are usually easy to replace, as long as you can get to it. Only 4 screws and nuts and 2013 shouldn't have any rust. Just rinse and drain it good and hold your breath. It only takes a few minutes.

BTW, the last valve I had to replace had a damaged slide where something was in the valve when it was closed. Oil wouldn't have helped.

[mooring_product]

Paradox123 wrote:
I used one of those temporarily, and they are OK if you stay in Florida, but in colder climates, whatever leaks past your main valve will freeze and become undumpable.

Never thought about that.

What about antifreeze in the problem tank? I also would think that most of us don't camp when its below freezing..

I have only used my heater twice

[billyray50]

I second the Valterra twist on valve cover. Had it two used older campers. No problems in colder weather either. Cheap and easy quick fix.

[Paradox123]

I used one of those temporarily, and they are OK if you stay in Florida, but in colder climates, whatever leaks past your main valve will freeze and become undumpable.

[mooring_product]

I have had this issue sense I purchased my Lance 881.

I rinsed and greased everything but couldn't get the grey water to hold.

I finally installed one off these last week. No more surprise splashes when dumping.
twist on valve

[Fastbrit]

Chalet rv had lots of problems with that mechanism also.The cables are too long.They now have electric valve for black and grey tank in they're campers.

[Paradox123]

I had this problem. The source was a bad mechanical design, not something stuck in the valve. I replaced the valve three years ago with a 12 volt electrically activated valve and have no further problems.

[Geterdone]

Thanks I will try these fixes....someone suggested dumping cooking oil in empty tank and flushing it thru to lube valve...? Not sure if that is a valid option.

[miskeeta]

Lance 981 here the only sure cure is put in a second knife at the very end of the line been there done that

[naturist]

A bit of rubble in the grove is my guess, too. Could be 'bout anything. My black tank had a similar problem, that turned out to be the plastic cutout from when they drilled the hole in the top of the tank to install the toilet. It was "found" near the end of a thorough cleaning/flushing, so when I had to reach up the pipe and pull it out, it wasn't entirely nasty.

Rinse the tank well, that might dislodge it. Fill the tank FULL of clean water and do a complete dump. If that doesn't clear it, you, too, might be a candidate for reaching waaaaaaayyy up in there and running a finger around the groove . . . .

[dends]

If you find the answer let me know , have same camper with same problem. Design flaw ?

[Old-Biscuit]

Probably have something in blade valve grove.
Cable operate valves will not close at tight when stuff builds up in grove due to flex in cable.

Sometimes you can clean out grove by heavy flushing or by back flushing while partially open/closing valve.

If seals are cause of leak.......usually end up having to replace.

[Super_Dave]

They make a cap with a hose fitting on it to back flush the valve in case something that went down the drain is trapped at the valve, preventing it from closing all the way.