The water supply tube from our old dishwasher is hard plastic. It's not flexible enough to meet the connector on the dishwasher. The fitting near the water supply shut off under the sink was smooth around the outside and we couldn't get it to budge with pliers.

We are trying to replace this hard tubing with a universal dishwasher connector but can't remove the old plastic. Afraid we will break something if we force it. Once we get the plastic off, how do we get the brass PEX fitting to match the universal?

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  • A photo of the pipe and shutoff valve connection would really help. – BMitch Apr 6 '16 at 2:45
  • Looks like the fitting was soldered onto the valve, and then the plastic was attached. You may have to replace the soldered component. – Daniel Griscom Apr 6 '16 at 11:21

There are many ways to skin this cat. But probably the easiest one would be to cut the plastic pipe so that there is no water in it. The reason you want to remove the water is so that you can then use a hair dryer to get the plastic warm and soft. Use two pliers- one to brace the copper valve and the other to twist the plastic pipe or connector off.

If that's not working, a pipe sander or dremel tool (with a cut off wheel) could probably chew through that connector pretty quickly, but I suppose you could also try using a box cutter to cut into the connector (which looks like it will be easy if it's warm and soft). But just be careful to not cut too deeply or you might damage some copper or brass threads. You should cut most of the way through the connector and then maybe use a small flat head screw driver to pry the connector loose.


i have to admit, i have never seen that type of plastic fitting. just cut the copper pipe off and reinstall a normal compression type replacement valve and you can connect the supply line to a nice new valve. total cost is about 9 minutes and $12

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