I need to replace the right rear brake line as it rusted out. What size are the lines and fittings?

Sounds like a leak in the brake line.
In the first place the front disc brakes do 70% of the work to stop the vehicle .
When you need to bleed your brakes you break into the system this lets fluid out air will get in every time so even a pin hole in the line or at a fitting will let air in slowly .The problem is air is compressible fluid is not so look for leaks at rear lines and fittings its vary common for rear lines to rust out and many inexpensive ways to repair them .
An other thing to know is when bleeding brakes is if you didn't open the front lines you don't need to bleed them but with the rears start with the farthest one away from the master cylinder passenger side rear 99% of the time and work back to the master .
I think your whole problem is a rusted out line 94 thats a lot of road salt good luck

your brake line is rusted and has a pin hole letting the fluid out. You will need to have the line replaced.

What you need to do is take off the original line. If you check on the Web, you may find some kits for a complete system, but an individual line is often difficult to ship.

There are different size fittings on the ends of brake lines. In some cases, the Universal lines may work, but the end fittings must match your vehicle. This is why taking the old line with you is important.

Some mechanics get coils of brake lines and bend and fit the ends themselves. It takes a few specialized hand tools to accomplish this. They are not terribly expensive, but for 1 line it is not worth it and it takes some skill to properly install the fittings on the line.

Now you have a 14 Year old car, and I can't recall when they stopped all production. But even a later model may be too old for them to stock a Factory replacement part.

A good brake shop would be your best bet. Call ahead and ask if they can make a line to replace what you have. It should not take but a 1/2 hour or so to swap out what you have, then some time to bleed the brakes.

One thing to consider- ALL lines were new at the same time. If one rusts out, there are few reasons for corrosion to be any worse for the failed line than the rest of the lines on your van. The exception would be collision replacements in which some brake lines might be newer than your van.

Don't do this unless you have skill at and tools to repair flair pipe. You will need the special tubing wrenches as well. The fittings/pipe are probably rusted and - frankly - it will be a night mare getting the repair done ... and then the 'fun' begins when you try to get the air out of the line.

This is a pain job. Wear safety goggles, as you will probably have rust falling down on you as you work. The brake line fittings will be difficult to separate. Soak the fittings with some penetrating oil for several days to make them easier to take apart. Get a pair of vise grips on the fitting that you want to loosen, and another pair where it attaches to the next line. Make sure the line you don't want to change doesn't turn, as it is common for the lines to be fused together with rust, and many times the 'good' line breaks off at the connection, requiring you to replace more lines. Parts stores have different sizes and length brake lines, and they are quite cheap. Bring the old line in for them to match up the fitting size on both ends and the length. You will have to bend them to match the original, just do it slowly so you don't 'kink' them (they are junk if that happens, and you will have to start over). You will then have to bleed the brakes to remove air in the lines. Good luck.

You can take the line off and take to a parts store that sells metal brake pipes by the foot,there is different size pipes as well as flared end nuts.You will have to bend the pipe to fit then bleed the brake system.Iwould suggest to take it to a shop and have a pipe made up.

If you want to do this yourself, just remove the brakeline. Go to a parts store and buy the length of brake line that you need. Most brake lines are 3/8" or 1/4" so get the right size. Get the brake line fittings. You will need tubing cutter, tubing bender, and flairing tool. Just cut it to the right length, bend it to the right shape, and install it. Presto!!! New brake line! Hope this helps. Good luck.

what i usually do if the money is available is purchase the brake lines in all sizes from the auto parts store and return any unused parts to the auto parts store,for a refund. they usually know the sizes you need ; you could also do the front first then the rear, or replace one line to get the size, also need a tubing bender to bend the brake lines, 'bleeder screws are usually three choices or go to ford or mercury, once you get started its not too bad, beware of compression fittings (unsafe to do it that way) Good Luck .

I’m happy to help further over the phone at https://www.6ya.com/expert/gregory_8e6ba270263743ac

Depends on your mechanic ablilites. Steel brake line is basically 0.188 inch diameter line, and the metric 6mm line dia is very closely same.
Dodge uses ISO bubble flare , and not the American standard double flare at the end of the steel tube line. This ISO bubble flare on the steel line then fits into its mate female end which is the rubber hose connector end.
So, easiest way to get rid of the ISO bubble flare and change to American double flare end is:
Some automotive stores such as Parts Plus Auto Stores carry the brass brakeline adapter which has one end being the male end that fits nicely into the rubber hose with its ISO bubble female fitting, while the other end of the brass line adapter is the female end which has the double flare so you can then insert the steel line replacement with standard double flare into this end of the adapter.
Steel line , bungy brake line or equivalent is fine, and has the brake line nuts already on it, and is flared for you too. If you want to stay with ISO bubble line fittings you can get that in bungy brake line lengths too but it is less common for some stores to carry, and that is why the conversion brake line fitting adapter mentioned is so easy a way to change from ISO bubble flare to a double flare for easier use of all steel line being standard American double flared brake line. The brake lines come in straight lengths, 2ft 4ft, and 6ft, so you can use them to fit your necessary total length by connecting them with tubing couplers which the steel tube lines brake line nut gets threaded into.
My same year Durango had its rear line blow thru last year, due to the rusting of the steel brake line. I just got done last week, doing a entire steel line replacement myself. It was a medium sized effort for sure. You should check the other lines for the entire brake system to see if you need to replace more than just that section which failed for you, as my lines showed heavy corrosion at many other locations in the brake line system.
It is easy to double flare brake line tubing , and Sears sells its craftsman brand of brake line double flare tool kit for that purpose at about 60 bucks if I recall it right.
One thing you should do when doing your own double flaring, is to use a dial caliper to measure the diameter of the flare at its widest flared end, to insure you are within the required diameter of flare to insure proper sealing when you tighten down the tube flare nuts. I recall the flare diameter is supposed to be 0.272 inches , plus or minus 0.006 inches ( so range of dial caliper measuring of that formed flare should be between 0.266 inch and 0.278 inch) to insure the right diameter of flare for good sealing.
You can also get steel galvanized tubing line in coils of 20ft and more, with a bunch of brake line nuts ( all this is standard american brake line nuts, for double flared line fitting) from Inline Tube company; www.inlinetube.com.
Check out the great tech info from FEDHILL website, www.fedhillusa.com
Good luck, I did it so you can do it and feel satisfied and safe for the family with solid and sound steel line that is much better than chancing an accident via leaving the rusted line in place.