Expect to find the original steel brake lines in dangerous condition.  A half century of abuse and corrosion will take their toll.  While not exactly fun, fabricating new brake lines is not too difficult.  The same techniques, with proper sized tubing, can be used to build new fuel lines.

A special type of tubing will make all the difference in the world when building new lines.  Parts stores generally only stock precut, preflared lengths.  These precut pieces are made from a type of steel that is very difficult to fabricate.  It is too stiff and almost impossible to flare with hand tools.  It is not uncommon to kink the tubing when trying to bend these precut lengths.  The precut lengths require splices when you need a long piece, too.  Fortunately, a far superior product is available from Bendix.  It comes in a 25' roll.  It has a dull gray galvanized coating for better corrosion resistance than the bare shiny steel of the precut pieces.  Here is a scan of the label to help you locate some.  NAPA carries this as part # BK 6414000.  A roll of bulk tubing is also cheaper than a bunch of precut lengths.

Here are some of the tools you will need.  My double flaring set was made by Blackhawk, but there are many brands available.  Get a good quality set from a reputable manufacturer for consistent results.  Avoid overseas brands with names like Fling Dung or similar.  In the upper right corner of the red case, note the five double flare adapters for different size tubing.:

Before you try making any finished lines, practice, practice, practice.  The most important part, and this bears repeating, is to start with a nice square cut.  If the end of the tube is uneven, there is no way to produce a good double flare.  Here a tubing cutter is being used to produce the square cut needed.  Cut the tubing a few inches long at this point:

The tubing cutter will slightly compress the end of the tubing.  Most tubing cutters have a reamer that folds out for deburring the inside or you can use a thin needle file.  Clean up the sharp outside edge with a light pass of a file.  Blow out any debris with compressed air.

To start the flaring operation, first slip the flare nut on the tubing.  Don't ask how many times I've formed perfect flares on both ends with the flare nuts still sitting on the bench.  The double flare adapters have a shoulder to indicate how far the tubing should stick out from the flaring bar.  The handle from the flaring tool is used to tighten the large wing nuts.  You can hold the flaring bar in a vise for easier handling:

This close-up shows the shoulder on the adapter acting as a gauge to position the tube for the first flaring operation:

The protruding shank of the double flare adapter is inserted in the open end of the tubing.   For the initial flare, the flaring tool compresses the double flare adapter against the flaring bar and forms a bell shape:

For the final flare, the adapter is removed and the flaring tool tightened again.  Add a drop of oil under the point of the flaring tool for best results:

Here is a close-up of a finished double flare.  With good tools, a nice square cut and some practice you can make high quality double flares consistently:

The order in which you form bends must be thought out in advance.  When laying out lines, first form the flare at the end that is more difficult to fit.  At the less critical far end, you can determine the finished length after all bends are complete.  Don't forget to include the extra length that must stick out from the flaring bar.  

Keep in mind that the flare nuts won't pass around any corners.  Don't get the flare nuts trapped between bends during the bending process.  If a bend is needed close to a flare nut, the flaring should be done first.  Otherwise, you will need a straight section at least 1.25" since the flare nut must be in place behind the flaring bar.

A large radius can be bent by hand, but there are few applications with such large bends.  For almost all applications tubing benders are required.  The bender in the next picture works well but won't fit in tight quarters.  This type of bender makes a nice, tight radius.  Note how the bend can be placed close to the flare nut with this type of bender:

For tight quarters, this type of bender works well.  However, this bender can't get quite as close to the flare nut and also forms a larger radius:

Expect to make lots of mistakes initially.  If the bends or flares are less than perfect, get a new piece and try again.  The tubing is inexpensive and the safety of your brake system requires high quality workmanship.  

 

The front brake "S" shaped lines (actually spirals) are tricky to fabricate.  Since the bend will be so close to the flare nuts, conventional tubing benders won't work.  I made a crude jig from a 7/8" diameter dowel.  With a 3/16" diameter rat tail file, I formed a spiral groove for the tubing.  Starting with a straight 4.68" piece, flare nuts were installed and both ends were double flared.  One flare nut was held in a vise against the form and the free end was wrapped around.  For an extra bit of leverage, a 3/8" box-end wrench was used to grasp the flare nut on the free end.  Make sure your finished lines have no kinks or any other sort of damage. It took much experimentation with various tubing lengths and form diameters to get it right.  You may find different dimensions are needed but this worked well for me.  A finished "S" line is shown in the front axle section.

While working on your new brake lines, you can do a preliminary leak check with compressed air.  I held a rubber tipped air nozzle at the brake line junction block.  You could also fabricate an air hose fitting that threads in place.  The brake drums and shoes must be installed or the wheel cylinder pistons will fly out.  With the lines pressurized, brush soapy water over all the connections and look for bubbles.  30 or 40 psi is plenty and is safely well below the 500 psi that the master cylinder will apply.    However, this is a great time saver should you find a leak now when it is easy to access for repair.  After the entire brake system is connected, filled and bled, stand on the pedal for a few minutes and inspect all lines and connections for leakage.

While not difficult, fabricating these new lines was very time consuming.  Despite my best attempts, much trial and error was involved in locating the bends and fittings precisely.  Jp Magazine printed an article of mine about new brake lines supplied by Classic Tube for my Willys wagon.  The new lines from Classic Tube fit perfectly the first time and practically installed themselves.  The price was comparable to the raw materials and tools shown above.

Even if you don't replace the rigid lines, the flexible hoses are a critical item and should be replaced periodically.  The hoses have a lay line printed on them.  This is used to ensure the hose isn't twisted when installed.  If twisted, the hose will try to straighten when brake line pressure is applied and could unthread from the rigid lines.

Now you didn't ask, but here is my two cents worth about repairing brake cylinders.  Repair kits are available, with new seals, etc.  Generally, if your brake cylinders need repair, there is pitting inside the bore.  Should you try to hone out these pits, the bore is now oversized and the seals will leak.  I don't even bother trying to repair brake cylinders anymore.  I've wasted too much time disassembling, honing, reassembling, looking at the new leak, going back to the parts store, etc.  New cylinders don't cost much more than the repair kits and save a lot of time and frustration.