| Freshwater tank leaks when more than half full [message #251755] |
Sun, 08 June 2014 17:50  |
Otterwan
Messages: 946
Registered: July 2013
Location: Lynnwood (north of Seattl...
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Now before you even say it, the obvious answer is that there is a crack halfway up. That may indeed be the case, but I was wondering if anything else could be the problem?
If I fill the tank full (by the gauge, not until water comes out the vent), it drips very slowly out the back of the coach. If I drain it until the 3/4 light goes out, it can sit forever and not leak a drop. The system holds pressure and the pump does not cycle.
The tank is not easily accessible to inspect (Royale rear bath). Any thoughts?
1977 Birchaven, Lynnwood WA - "We may not be able to stop all evil in the world, but I know that how we treat one another is entirely up to us."
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| Re: Freshwater tank leaks when more than half full [message #251757 is a reply to message #251755] |
Sun, 08 June 2014 18:04  |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Otterwan wrote on Sun, 08 June 2014 18:50Now before you even say it, the obvious answer is that there is a crack halfway up. That may indeed be the case, but I was wondering if anything else could be the problem?
If I fill the tank full (by the gauge, not until water comes out the vent), it drips very slowly out the back of the coach. If I drain it until the 3/4 light goes out, it can sit forever and not leak a drop. The system holds pressure and the pump does not cycle.
The tank is not easily accessible to inspect (Royale rear bath). Any thoughts?
David,
As you are not doubt acutely aware, a Royale is not a GMC interior, so if ANYBODY else comes up with an answer, go with his before mine.
The level sending unit in a GMC tank is half way up the tank and though it was well made 40 years ago, mine had failed two ways. If it is the same part, I can almost guarantee it has failed. It will continue to provide readings for only a little while longer. There are two failure modes.
The moving shaft is sealed buy a silicon rubber tube that is allowed to torsion but remain tight at the ends, until it doesn't any longer. You can remove it from the tank and use stainless safety wire to make it seal again, that will last a small number of weeks.
Then you are at common mode failure number two.... Plate that the entire sending unit is mounted to and with - has corroded through. You can coat the entire surface with epoxy and it will last a while.
The sending unit that JimK sells is all plastic and magnetically coupled to the sender. The only problem I had is that the studs on my old tank were not long enough and I had to create special fasteners. Other people have not had that issue.
If you can figure out which end of the tank the sender is on, you may not have to remove it from the coach.
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
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| Re: Freshwater tank leaks when more than half full [message #251758 is a reply to message #251757] |
Sun, 08 June 2014 18:09 |
Otterwan
Messages: 946
Registered: July 2013
Location: Lynnwood (north of Seattl...
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Good information, but the only part of the tank that I can see is where the sending unit is attached, and it is completely dry.
1977 Birchaven, Lynnwood WA - "We may not be able to stop all evil in the world, but I know that how we treat one another is entirely up to us."
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| Re: Freshwater tank leaks when more than half full [message #251764 is a reply to message #251760] |
Sun, 08 June 2014 18:38 |
Otterwan
Messages: 946
Registered: July 2013
Location: Lynnwood (north of Seattl...
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That is similar to mine except the fill is on the opposite end from the sensors, and none of the sensors are leaking. Also my tank is mounted "long way up", that is on edge as compared to your photo. The drain valve is easy to get to and it is not leaking either, although it is stuck and doesn't move.
1977 Birchaven, Lynnwood WA - "We may not be able to stop all evil in the world, but I know that how we treat one another is entirely up to us."
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| Re: Freshwater tank leaks when more than half full [message #251780 is a reply to message #251777] |
Sun, 08 June 2014 20:22 |
Otterwan
Messages: 946
Registered: July 2013
Location: Lynnwood (north of Seattl...
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Funny that mine originally had the exact green and white fill hose shown in that image.
1977 Birchaven, Lynnwood WA - "We may not be able to stop all evil in the world, but I know that how we treat one another is entirely up to us."
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| Re: Freshwater tank leaks when more than half full [message #251792 is a reply to message #251758] |
Sun, 08 June 2014 22:22 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Otterwan wrote on Sun, 08 June 2014 17:09Good information, but the only part of the tank that I can see is where the sending unit is attached, and it is completely dry.
Once you reach a certain level, other systems may start leaking. i suspect your hot water tank.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Freshwater tank leaks when more than half full [message #251805 is a reply to message #251794] |
Mon, 09 June 2014 02:17 |
appie
Messages: 902
Registered: April 2013
Location: denmark
Karma: 2
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If the tank is 40 years I would consider getting a new and clean one, Then you can make all connections from the top, thus eliminating any chance of leaks.
Appie
eleganza 76 "Olga" now sadly sold
6 wheel discbrake
Quadrabags
Springfield stage 2 462 olds
Manny tranny
( pictures at http://www.gmcmhphotos.com/photos/g6489-olga.html
Fulltiming in Europe july 2014 til july 2016
Denmark
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