Dishwasher supply line connection/water inlet valve

[GregN31]

My dishwasher water inlet valve appears to be failing because I have a slow drip into the tub from the left side where the hot water comes in. It happens all the time, even if the breaker for the washer is turned off. I'm just going to replace the whole water inlet valve assembly.
(If there is an easier way to do it I'm all ears - my understanding is there isn't much I can do to service this thing, I think I just replace it).
My existing inlet valve assembly has the standard brass elbow threaded into it with teflon tape, and the supply line connected to it is flexible copper tubing that goes over 2 or 3 feet to under the sink and connects to a shut off valve. The tubing looks to be connected with a compression fitting to the shutoff valve. On the other side of the shut off valve is copper, just the bigger diameter.
I'm wondering when I do this what I have to do in terms of reconnecting everything.
Here is what I see under the dishwasher right now:


It looks like the copper connects to that brass elbow with a compression ferrule and a nut (I think).
The elbow is pretty gunked up, so I'll just buy a new one.
When I take the existing copper line off that existing elbow, what do I need to connect the flexible copper to a new compression fitting?
Can you reuse the copper where it was 'compressed' or do you have to cut it off back a bit? Any other preparation?
The distance from my dishwasher to the shut off valve is very short, the dishwasher is adjacent to the sink. Should I remove all of the copper flex line, and connect a braided stainless steel flex line from the existing shut off valve to the new elbow I put on the dishwasher. Is that better/easier?
Will the flex line connect to the existing shut off valve if I take the compression nut off over on that end?

This is probably really easy, but I want to make sure I do it leak free. I'm just not sure how to reuse the copper flex tubing and if I should.

Thanks.

[Jeff1]

I think one of the real plumbers will have to chime in here. But from a DIY perspective, I'd replace the copper with the flex line. If not, you need to inspect the copper to see if it can be reused or cut back first and see if it is long enough. If you keep the copper you may be able to reuse the compression nut if it will fit the new fitting. If you get a new elbow it may have the compression fittings on it. You'll have to make sure the flex line has the same size as the under sink fitting. I don't know about your inlet valve assembly, you'd need to research that some more.

[Basement_Lurker]

Wow, look at how the wiring is just slammed in there. You should have enough tubing slack left to cut off the existing end and compress on a new ferrule. I would just replace the line with a braided one and be done with it.

[cacher_chick]

If I were going to re-use the copper, I would cut the existing ends off and use new compression fittings. It would have to be long enough to do this.

A fine alternative would be to install a stainless steel braided flex hose which is available in a range of sized. I would NOT use the Watts Floodsafe hoses, as they have been known to fail with disastrous results.

There are a number of shut-off alternatives to be found.

[Terry]

If you use a braided connector, don't use Teflon Tape though. It interferes with the seal.
No Teflon tape on compression either

[Gary Swart]

Use a flexline with the braided steel mesh covering. A 1/4 turn shut off valve while you're at.

[hj]

All you HAVE to do is disconnect the copper tubing and the outlet hose, pull the wire connector off the valve, remove the valve bracket along with the valve. Get a new one which should have a bracket on it, screw it in and connect everything back again. Usually it is easier to do if you pull the dishwasher out, but it can be done with it in place.