If you take it to the parts store, you can get a stick of brake line with the correct fittings and length.

I'm making a trip to AZ, closest parts store, and see what they have. If have what I need, I'll replace the entire line now that I know both ends are flare nuts. Thanks. I'll post back later.

Love working on my Jeep again.

This was a nightmare. Not because was anything difficult. It isn't. I bought a 5 ft length of 3/16 inch brake line with fittings. Remove the old one. Then find that the fittings would not thread in. I measured the diameter of the fittings to be .387 , The original measures .368. Seems a labeled 3/16" Tube size may have had Metric threads or something weird. I ended up buying flare fittings and a compression union. I cut a section of the new brake line/tube. Cut out the bad section at the connector block. Put new flare on one end and joined it to the junction block with compression fitting joining the rest of the line.
I've NEVER had this much hassle with bleeding the brake line rear passenger side. I'm using the one person bleed kit. I cannot get the new section to bleed. Got frustrated so put it away for today. Tomorrow I will pull out that brake line and pump brake fluid thru it. Hoping not a blockage in the line. . Then before I reattach it, I'll see if can get brake fluid to pump to the block junction.
Any suggestions?
Before all this, when I pumped the brake, I saw fluid blasting out the broken line to the passenger side just after the block junction

Hang in there. Sometimes I think we just aren't holding our mouth right, lol. I have walked away for the day when things just weren't clicking.

Recently I ordered what was supposed to be OEM spec plastic push pins(Christmas trees) to reinstall my front inner fender liners only to realize the stems are about .022" smaller than the OEM. Therefore, they shove in really easy and I'm concerned that they won't hold. And I refuse to spend the money they are asking for Mopar ones.

As far as bleeding, though I have a mityvac to bleed brakes, sometimes the easiest thing to do when alone is to stick a hose from the bleeder into a jar with fluid, crack the bleeder and pump the pedal. Check the MC to be sure you don't run it dry, but do that until you get a pretty full jar and you should have the air out.

Its probably the rubber line, as I usually try to bleed things just with gravity, and if fluid doesnt run out, its cause the rubber lines are restricted

how old are they?

10yrs is old enough

I kept having problems with a caliper locking up on my wife's Fusion. Rebuilt the caliper. Still locked up. Replaced the caliper. Locked up again. I then surmised the hose was collapsing so I replaced it. Problem solved.

All good advice. Especially walking away, go inside and listen to the news. Well, not the news, some Motor Trend Roadkill episode.
Bizarre issue is that before all this, pumping the brakes, could see fluid coming out of the cracked line. Master Cylinder would definitely have fluid flowing. Now ,with the new line, nothing flowing out. Could be a bad line, plugged, kinked is possible. I bought a new line with the CORRECT FITTINGS. I will check that the brake line will flow fluid before I bend it. Then check after its bent. Then check flow before final connection at the drum. I suspect that the fittings I put on this first line may actually be blocking at that junction block. I'll do that when I get back to it later today. Thanks. There are some days we all have....

I may have to bleed the master brake. I tried using the bleed kit to pump fluid back up to the master brake . I disconnected at the rear junction. Connected at the compression union I used and Pumped from here to the front. Fluid was flowing and then stopped Hard solid. Not pumping any more fluid. Nothing is happening. And the level in the master cylinder did Not change.
Before all this, the only problem I had was the obvious crack in the brake line. I'd Pump the brake pedal , go real soft and obvious fluid would pour out of the line at the crack in the back. The master cylinder did go down a lot to near empty.
Now with a replaced line, I can't get it bled. NO change in the rear brake reservoir part of the master cylinder. The brake idiot light is on now. I am guessing because fluid is not moving in the master cylinder.
Do I loosen the front reservoir fitting On the master cylinder and bleed it. Should I empty the front reservoir (for Rear Brake) and try bleed again?
Need advice. Thanks
==============================
Will a Master Cylinder cause this hard stopping when trying to reverse bleed from the back lines to the front. It acts like it hit a solid block. Fluid pumped forward and then stopped hard.

I believe I have read that the act of bleeding the brakes can cause the proportioning valve to jam in its seat, so it might be worth taking that apart to see if that is the problem

The way I bleed brakes is different to most people, I start with the closest one to the MC and let it run out, then work away to the furthest

Also take the bleed screw out and make sure its clear..the rears on my XJ were blocked

If a gravity bleed wont work, something is usually wrong, so then I work my way back to see what the issue is, crack every union, bleed the MC etc etc

Can that valve be 'cleaned; out if that is the problem. Wow, they are expensive to replace. Can it be rebuilt, assume new seals .
I assume its located as in other Jeeps near the driver side fender. I'll address that today.
Again, some advice needed. Should I drain the MC and then the entire brake system?. A simple brake line replacement turned worse.

I wouldn't just yet.
Is there clean fluid in the master now?
Do you have an air compressor?

My air compressor is in storage 60 miles away. . What would I do if I go get it or can borrow one. The fluid is old. I'm thinking I can use the bleed kit with hand pump to blow the brake fluid out the back.

I have the line disconnected at the rear passenger side drums. I was able to put fluid reversed fill from the rear passenger brake up to the front- no fluid made it into the MC. Stopped pumping fluid hard and couldn't pump anymore. No fluid is coming out the open passenger rear brake line when I depress the brake pedal. Thinking no fluid is getting pumped out. So is it screwed up either at the MC and before or after the proportional valve. How can I isolate being a rear brake line issue.
===========================
I don't think the MC bleed was empty. If it did, would this kind of problem happen?

Loosen the fitting at the MC, pump the pedal and see if there is strong pressure there?

I will be working on it soon. With engine off, the pedal is a hard push and solid. Moves minimal. Pedal does not goes down. Hand brake is off.
Start engine, brake pedal will go down. Not solid stop. And no brake fluid flowing out the rear brake line

Sounds like a bad MC to me.