Thetford toilet leaks down

LarryW

LarryW

Well-known member
Mar 28, 2002
6,022
744
113
Menomonie, WI.
So...I've got this Thetford toilet, that I installed back in 2006. If I put a couple of inches of water in the bowl, it leaks down into the holding
tank in about 1hr. I'm not familiar with the internal construction of it, so need to know if there is a gasket/"O"ring or something in there that drys
out and leaks, and if so is it and how is it replaced. Anyone???? TIA
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
> So...I've got this Thetford toilet, that I installed back in 2006. If I put a couple of inches of water in the bowl, it leaks down into the
> holding tank in about 1hr. I'm not familiar with the internal construction of it, so need to know if there is a gasket/"O"ring or something in there
> that drys out and leaks, and if so is it and how is it replaced. Anyone???? TIA

Larry,

The problem varies form model to model, but a common issue is calcium fouling of the valve parts. So, the first try should be pouring a little dilute
HCl like CLR or the like. It may take a couple of passes if it works at all. Mine got bad enough that I had to take it apart and clean them
individually, but that held for a few years. Rebuild kits are available, just don't order them from Thetford if you need it soon.

I live a few miles away and when I ordered parts, they didn't show up in good time. So, I called again and was told that they wait three days before
shipping anything. Order from a reliable supplier in stead.

Again model dependent, they are all more or less easy to service. The type with a flat blade valve are a spin off of the Thetford valve and work just
like it.

I suggest that you do this before the weather goes cold. The most difficult part with most of the Thetford pots is dismounting it.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
Almost all will leak down due to age of gasket and build up.
If your concerned about oder, pore water into the floor drain as it will
fill that goose neck and not gas will travel....

> > So...I've got this Thetford toilet, that I installed back in 2006. If I
> put a couple of inches of water in the bowl, it leaks down into the
> > holding tank in about 1hr. I'm not familiar with the internal
> construction of it, so need to know if there is a gasket/"O"ring or
> something in there
> > that drys out and leaks, and if so is it and how is it replaced.
> Anyone???? TIA
>
> Larry,
>
> The problem varies form model to model, but a common issue is calcium
> fouling of the valve parts. So, the first try should be pouring a little
> dilute
> HCl like CLR or the like. It may take a couple of passes if it works at
> all. Mine got bad enough that I had to take it apart and clean them
> individually, but that held for a few years. Rebuild kits are available,
> just don't order them from Thetford if you need it soon.
>
> I live a few miles away and when I ordered parts, they didn't show up in
> good time. So, I called again and was told that they wait three days before
> shipping anything. Order from a reliable supplier in stead.
>
> Again model dependent, they are all more or less easy to service. The
> type with a flat blade valve are a spin off of the Thetford valve and work
> just
> like it.
>
> I suggest that you do this before the weather goes cold. The most
> difficult part with most of the Thetford pots is dismounting it.
>
> Matt
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
I spent several DAYS trying to install the repair kit. Damn big O ring from
the Thetford kit don't fit, and it leaked after I repaired it. Went to plan
"B". Threw the Thetford plastic toilet into the trash where it belongs, and
replaced it with a ceramic bowl one from their competitor. Just went to the
coach to put some frozen Lobster tails into the Fridge for Judy's 80th
birthday party, and I checked the toilet bowl. Yep, still holding water,
just like it was a month ago.
Jim Hupy
Salem, Oregon

> So...I've got this Thetford toilet, that I installed back in 2006. If I
> put a couple of inches of water in the bowl, it leaks down into the holding
> tank in about 1hr. I'm not familiar with the internal construction of it,
> so need to know if there is a gasket/"O"ring or something in there that drys
> out and leaks, and if so is it and how is it replaced. Anyone???? TIA
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
 
Larry,

I've sometimes had good luck using an old toothbrush and a bit of detergent
to scrub the gasket around the lip of the opened valve. It's probably only
successful if a bit of paper has been trapped, but it's a Q&E fix, so worth
trying. Can be smelly tho'. :-)

Ken H.

> So...I've got this Thetford toilet, that I installed back in 2006. If I
> put a couple of inches of water in the bowl, it leaks down into the holding
> tank in about 1hr. I'm not familiar with the internal construction of it,
> so need to know if there is a gasket/"O"ring or something in there that drys
> out and leaks, and if so is it and how is it replaced. Anyone???? TIA
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
 
Yep like Ken says first step is a good cleaning. Maybe some simple green and a round toilet brush and go round and round with water pump off and pedal
to floor. Then repeat with water on. Yours is not old enough to be worn out IMHO.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
Larry,
I've had good luck with a little tool I found that is mean to turn steaks on the grill. It has a point on a curved section that goes into the gate
valve groove in case some tissue gets trapped in there. Needless to say I don't use it for steaks.
Doug
--
Douglas & Virginia Smith,
dsmithy18 at gmail,
Lincoln Nebraska,
’73 “Sequoia” since ‘95: "Wanabizo";
Quadrabag/6 wheel disks/3:70 final/Paterson QuadraJet/Thorley’s/Alloy wheels/Sundry other
 
> Larry,
> I've had good luck with a little tool I found that is mean to turn steaks on the grill. It has a point on a curved section that goes into the gate
> valve groove in case some tissue gets trapped in there. Needless to say I don't use it for steaks.
> Doug

Doug,

That sounds a lot like the "bent screwdriver" tool that Thetford used to sell for cleaning the seal. I don't know if they still sell it.

Matt

--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
I'm not sure I get the point of this whole thread. Is your toilet supposed to hold water all the time? Ours flushes normally, doesn't smell and I've
never even checked to see if it holds water. My little tissue removal tool only sees use when the gate valve is obviously not fully closing.
--
Douglas & Virginia Smith,
dsmithy18 at gmail,
Lincoln Nebraska,
’73 “Sequoia” since ‘95: "Wanabizo";
Quadrabag/6 wheel disks/3:70 final/Paterson QuadraJet/Thorley’s/Alloy wheels/Sundry other
 
There is no trap under an RV toilet to prevent sewer gasses from traveling
through the toilet. That is the purpose of the water in the toilet. Just
because you cannot smell a colorless, odorless, volatile gas does not mean
that it is not harmful. Again, that is what the water does.
Jim Hupy
Salem, Oregon

> I'm not sure I get the point of this whole thread. Is your toilet supposed
> to hold water all the time? Ours flushes normally, doesn't smell and I've
> never even checked to see if it holds water. My little tissue removal tool
> only sees use when the gate valve is obviously not fully closing.
> --
> Douglas & Virginia Smith,
> dsmithy18 at gmail,
> Lincoln Nebraska,
> ’73 “Sequoia” since ‘95: "Wanabizo";
> Quadrabag/6 wheel disks/3:70 final/Paterson QuadraJet/Thorley’s/Alloy
> wheels/Sundry other
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
 
Thanks Jim!

>
> There is no trap under an RV toilet to prevent sewer gasses from traveling
> through the toilet. That is the purpose of the water in the toilet. Just
> because you cannot smell a colorless, odorless, volatile gas does not mean
> that it is not harmful. Again, that is what the water does.
> Jim Hupy
> Salem, Oregon
>

>
>> I'm not sure I get the point of this whole thread. Is your toilet supposed
>> to hold water all the time? Ours flushes normally, doesn't smell and I've
>> never even checked to see if it holds water. My little tissue removal tool
>> only sees use when the gate valve is obviously not fully closing.
>> --
>> Douglas & Virginia Smith,
>> dsmithy18 at gmail,
>> Lincoln Nebraska,
>> ’73 “Sequoia” since ‘95: "Wanabizo";
>> Quadrabag/6 wheel disks/3:70 final/Paterson QuadraJet/Thorley’s/Alloy
>> wheels/Sundry other
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
 
I believe Thetford makes a toilet seal lube and conditioner.... Worked well to stop the slow leak on our electramagic recirculating toilet....
--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
 
I use the Thedford Seal Conditioner about once a year. Seems to work
without issue.

J.R. Wright
GMC Great Laker
GMCGL Tech Editor
GMC Eastern States
GMCMHI
TZE Zone Restorations
78 Buskirk Custom 29.5' Stretch
75 Avion (Under going Frame up Restoration)

On Sat, Sep 11, 2021 at 10:07 PM Mark Sawyer
wrote:

> I believe Thetford makes a toilet seal lube and conditioner.... Worked
> well to stop the slow leak on our electramagic recirculating toilet....
> --
> Mark S. '73 Painted Desert,
> Manny 1 Ton Front End,
> Howell Injection,
> Leigh Harrison 4bag and Rear Brakes,
> Fort Worth, TX
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
 
Cleaning and replacement solved mine. Silicone spray lubricant every now and then has kept rubber seal pliable.
--
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
 
Thetford does make a seal lubricant, conditioner. not sure if that will help, or just put more money in their pocket.

my dometic does the same thing, I Have tried a few things like Olive oil a few years ago. It did help, but just would drain down over night rather
then an hour.

--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
 
On the trouble shooting guide for my Sea-Land, one of the suggestions for fixing this was to tighten the clamp (a big screw clamp like a hose clamp)
around the valve. I tried it and it was already really tight, so I don't know if that really helped or not. A good cleaning of the sealing surface
usually works for a while anyway, but mine leaks down at random times anyway.

--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
 
Thanks for all of the suggestions. After the GMCMI convention, when we get home I plan to use some of the suggestions to hopefully fix the "leak". I'm
just glad that I don't have to take it apart to replace a "O"ring of some kind. Was not looking forward to that.
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
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