Old Style Plumbing

Great details myredracer!Encouraging DAhose! Thanks. Man O Man this is a great place for answers.

I had to extend some hoses when I replaced my toilet on my 1983 Jamboree. My local RV and marine supplier had push on fittings and hose. Worked great with my existing grey hose and the fitting was a couple bucks.

Jose

My understanding is that PB pipe is perfectly fine, it's fittings that aren't. You can connect PB to PEX but you need the proper transition/conversion/adapter fitting. The OD is the same but the ID is different thus can't use a standard PEX fitting. If it were me, I would take a sample piece of the PB pipe to a plumbing wholesaler and they can set you up with the correct bits and pieces. Don't go to a retail store.

I like copper crimp rings. You can rent the tool at most rental yards. A PEX crimper is large and hard to get into some locations though. I would suggest using a PEX cinch clamp like in the pic below (not a hose clamp). The tool doesn't cost a lot. Sharkbite fittings are fine but will get expensive if you need a bunch of them.

Connections to a faucet, toilet and HWH use a standard "swivel" fitting and you want to connect PEX directly to them and are available in elbow or straight style. Not sure what your line to the toilet looks like but nowadays it's a whitish re-enforced flexible tubing that is typically connected to a PEX fitting with a cinch clamp. I would replace that too (available from an RV parts vendor).

When buying PEX tubing, get it in straight lengths and not in coils. The coiled stuff is difficult to work with because it has a memory and will not straighten out and stay straight. Don't secure/clamp it down tightly everywhere because it does expand and contract with temp. changes. Use a PEX tubing cutter to ensure clean & square cuts. There's also a tool for making bevel cuts when using sharkbite fittings to minimize the chances of a leak.

There a number of ways to connect PEX tubing: 6 ways to connect PEX

Some info. on past issues with PB pipe and other types of plastic pipe (ABS, PVC, etc.) here: plastic piping issues

Nice responses all! Polybutylene is the correct name. So - I take it I can just add on the Pex (which I have heard of). That would be great! I also heard of the shark bites. Can add as well? It seems as though I can leave whats there in place and just add on? I did hear the Polybutylene was not made anymore...and in fact there were issues with it. I basically need to add a shower and sink fixture. They cut the original hoses. So I guess I would tap into the existing tubing to lead up to the fixtures. I can actually use standard fixtures?

X-2 to use PEX and Shark Bite fittings. Works great and makes for easy additions to the grey tubing plumbing.

"Qest" (that's the proper spelling) tubing and fittings (fittings are the same grey color) are readily available at HomeDepot and many other places. It's a good product and will last forever unless you use silver clamps - use the fittings instead. It even had the ability to freeze once without damage. There's no reason to replace it unless it has the bad clamps. Even then, just replace the fittings.

There could be a case made for replacing all of the Qest plumbing with PEX.

Our trailer also has the old style plumbing - it is called polybutylene. I've replaced quite a bit of it with Pex over the years. The good thing about it is that you can use the Pex fittings on it that you can get at Lowes or HD. Just bring in a chunk of the pipe and you can match the fittings right up. Then you can add Pex tubing to wherever you want to go.

Also - yes you can use faucets from these stores to replace the standard RV ones - just check out how many holes there are in the mounting area. For instance we replaced our bathroom faucet with a bar sink faucet because there was no middle hole for the drain lever.

Polybutylene (PB) pipe is the gray tubing that was made between the late 70’s and mid 90’s.
The 'Quest' fittings are no longer made or available

PB pipe outside diameter is same as PEX so push on PEX fittings/valves can be used.
Sharkbite (Home Depot) Gatorbites (Lowes), Flair-It and SeeTech/Watts will all work

That grey stuff is not PEX, it's called "Qest" and some home supply places still have fittings for it (locally, McClendons has it). I don't believe it is used for new work anyplace.
Qest was plagued by leaks caused by aluminum clamps. If you have copper clamps then it's good to go and will last forever. If it has silver clamps then they like to slowly loosen, stretch and leak. You can buy compression fittings to replace the clamp style parts or you may be able to find Shark-Bite fittings.