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Replacing Water Lines [message #67863] Sun, 20 December 2009 15:04 Go to next message
GeorgeRud is currently offline  GeorgeRud   United States
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Now that winter is upon us in the midwest, it's time to consider inside projects.

My coach needs to have the fresh water tank and water heater replaced, and I was wondering if it makes sense to try to replace the old water lines at the same time? They are original and I did have leaks in the water tank and heater, so the system is shwoing it's age.

Has anyone done this? Is there a better way to place drain valves so they are easier to access? Should PEX lines be used or is there a better alternative? Is getting rid of the city water connection a good idea, or can it be moved to a more accessable location if it needs repair?

Any advice would be much appreciated before I get involved over my head. It doesn't look like that big a job, but there's nothing better than hearing from people that have actually gone there before!


George Rudawsky
Chicago, IL
75 Palm Beach

[Updated on: Sun, 20 December 2009 15:07]

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Re: Replacing Water Lines [message #67866 is a reply to message #67863] Sun, 20 December 2009 15:44 Go to previous messageGo to next message
idrob is currently offline  idrob   United States
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Location: Central Idaho
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GeorgeRud wrote on Sun, 20 December 2009 13:04



My coach needs to have the fresh water tank and water heater replaced, and I was wondering if it makes sense to try to replace the old water lines at the same time? They are original and I did have leaks in the water tank and heater, so the system is shwoing it's age.

Has anyone done this? Is there a better way to place drain valves so they are easier to access? Should PEX lines be used or is there a better alternative? Is getting rid of the city water connection a good idea, or can it be moved to a more accessable location if it needs repair?




If your coach has the gray plastic lines they may be just fine, but the connections could be replaced as they are the real source of leaks, not the pipe itself. There have been some issues with new fittings on the gray lines, but I personally have any problems as long as the new fittings have an internal support for the inside of the gray pipe, so when the fitting is fastened, the gray pipe does not distort.

PEX pipe is the latest and is excellent in all ways. It is not quite as flexible as the original gray pipe. New fittings available at the home centers work very well with PEX, Sharkbite, Tigerbite, crimp ring type, and even the plastic ones that the RV centers seem to sell. Sharkbite and Tigerbite fittings are not inexpensive, and are a bit bulky, but work well with both PEX and the original gray plastic that GMC used after they stopped with copper. They simply push on and never leak.

It is not hard to replace the pipe in the bath area and pump areas of the coach, the hardest is the lines to the kitchen sink (if you have a sink on the drivers side, a very common setup). Those sink lines go up overhead and without removing the headliner are impossible to replace. If you have gray plastic lines, I would leave them in place, but change the fittings.

That is kind of a generic answer, but it may help, and others may chime in here.

As always, the information is personal observation and opinion, but I believe it is fairly accurate.




Rob Allen
former owner of '76 x-PB
Re: [GMCnet] Replacing Water Lines [message #67871 is a reply to message #67866] Sun, 20 December 2009 16:28 Go to previous messageGo to next message
powerjon is currently offline  powerjon   United States
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Registered: January 2004
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George,
I vote for the new PEX system when I replace the lines in the 75 Avion
that is now under reconstruction. The Avion came with all copper
water piping. The modern PEX piping is not suppose to break when
frozen if you cannot get all the water out of the lines. I also agree
that the older gray plastic that came with most of the coaches if not
damaged should be just fine and not necessarily be replaced.

J.R. Wright

>
>> My coach needs to have the fresh water tank and water heater
>> replaced, and I was wondering if it makes sense to try to replace
>> the old water lines at the same time? They are original and I did
>> have leaks in the water tank and heater, so the system is showing
>> it's age.
>>
>> Has anyone done this? Is there a better way to place drain valves
>> so they are easier to access? Should PEX lines be used or is there
>> a better alternative? Is getting rid of the city water connection
>> a good idea, or can it be moved to a more accessible location if it
>> needs repair?
>
>
> If your coach has the gray plastic lines they may be just fine, but
> the connections could be replaced as they are the real source of
> leaks, not the pipe itself. There have been some issues with new
> fittings on the gray lines, but I personally have any problems as
> long as the new fittings have an internal support for the inside of
> the gray pipe, so when the fitting is fastened, the gray pipe does
> not distort.
>
> PEX pipe is the latest and is excellent in all ways. It is not
> quite as flexible as the original gray pipe. New fittings
> available at the home centers work very well with PEX, Sharkbite,
> Tigerbite, crimp ring type, and even the plastic ones that the RV
> centers seem to sell. Sharkbite and Tigerbite fittings are not
> inexpensive, and are a bit bulky, but work well with both PEX and
> the original gray plastic that GMC used after they stopped with
> copper. They simply push on and never leak.
>
> It is not hard to replace the pipe in the bath area and pump areas
> of the coach, the hardest is the lines to the kitchen sink (if you
> have a sink on the drivers side, a very common setup). Those sink
> lines go up overhead and without removing the headliner are
> impossible to replace. If you have gray plastic lines, I would
> leave them in place, but change the fittings.
>
> That is kind of a generic answer, but it may help, and others may
> chime in here.
>
> As always, the information is personal observation and opinion, but
> I believe it is fairly accurate.
>
>

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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
Re: Replacing Water Lines [message #67905 is a reply to message #67863] Sun, 20 December 2009 21:52 Go to previous messageGo to next message
GeorgeRud is currently offline  GeorgeRud   United States
Messages: 1380
Registered: February 2007
Location: Chicago, IL
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Senior Member
My coach has a mix of grey and black lines, and some white lines to and from the water pump. The fact that some of the drain valves are not at the low points of the runs makes me think that they may have been replaced at sometime, or at least fiddled with. I do have the roof panels off, so it may be a good time to try to do this (or at least change the fittings).

I'm still thinking of what to do with the city water fitting. I definitely want to avoid having to get into that cavity again if at all possible, as I do have a major leak in there right now.


George Rudawsky
Chicago, IL
75 Palm Beach
Re: Replacing Water Lines [message #67916 is a reply to message #67905] Sun, 20 December 2009 22:57 Go to previous messageGo to next message
hal kading is currently offline  hal kading   United States
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Registered: February 2004
Location: Las Cruces NM
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Senior Member
I like the 3/8" pex for the hot water lines. You don't waste so much getting the hot water to the faucet and the flow seems adequate to me.

Hal Kading 77 Kingsley 455 Las Cruces NM
Re: Replacing Water Lines [message #67919 is a reply to message #67863] Sun, 20 December 2009 23:33 Go to previous messageGo to next message
zhagrieb is currently offline  zhagrieb   United States
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Registered: August 2009
Location: Portland Oregon
Karma: 0
Senior Member
I replaced my entire system with 3/8 PEX. I used crimp fittings with great success. The crimp tool is a bit clumsy and difficult to work in confined spaces but the pipe is flexible enough so with careful planning you can pull the joints out where they are more accessible, make the crimp, then push it back into place. I chose the 10 foot straight lengths rather than the coils as the coiled stuff likes to stay coiled. The straight pipe will cost more but makes a neater installation.

I enclosed my fresh water tank and the pump in a compartment lined with heavy shower pan plastic. I put a tub drain through the plastic and the floor of the coach to allow any leakage out, I then installed drain valves for the tank and for the plumbing in this space. I put two additional drain valves under the kitchen sink. I winterize by opening all valves (especially the water heater), blowing some compressed air in through the "shore" water connection, and pouring a little pink antifreeze into the traps. I don't put anything in the water lines.

You can put the shore water connection most anywhere. In the propane compartment is one choice.

Lowes has the crimp tool for about $85, Harbor freight has one much cheaper but i don't know if the saving is worth the ?? of the Harbor Freight tool. Be sure to use the go-nogo gage that comes with the tool. You'll also want a crimp cutter as you'll certainly have joints you'll want to redo.

Everything came from Lowes.

Glenn Giere


Glenn Giere, Portland OR, K7GAG '73 "Moby the Motorhome" 26'
Re: [GMCnet] Replacing Water Lines [message #67928 is a reply to message #67863] Mon, 21 December 2009 00:57 Go to previous message
Steven Ferguson is currently offline  Steven Ferguson   United States
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Registered: May 2006
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Senior Member
George,
My experience is not with the lines going bad, it has been the
fittings. Every water leak I've had in the GMC is because of the
fittings going bad from being overtightened, or just old age. I don't
know which.

On Sun, Dec 20, 2009 at 1:05 PM, George Rudawsky <GeorgeRud@aol.com> wrote:
>
>
> Now that winter is upon us in the midwest, it's time to consider inside projects.
>
> My coach needs to have the fresh water tank and water heater replaced, and I was wondering if it makes sense to try to replace the old water lines at the same time?  They are original and I did have leaks in the water tank and heater, so the system is shwoing it's age.
>
> Has anyone done this?  Is there a better way to place drain valves so they are easier to access?  Should PEX lines be used or is there a better alternative?
>
> Any advice would be much appreciated before I get involved over my head.  It doesn't look like that big a job, but there's nothing better than hearing from people that have actually gone there before!
> --
> George Rudawsky
> Chicago, IL
> 75 Palm Beach
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>



--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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