1971 Body/Chassis FSM

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Making Your Own Brake Lines


I started to title this: Easily Making Your Own Brake Lines, but this is one of those jobs that requires a couple of special tools, and one of them takes a bit of practice to use it correctly. So...

We will start with the fact that Rainman (Rainey Kirk), a respected MUD member, makes complete sets of brake lines for ALL FJ40's and now FJ55's! Here is the link to his site: Rainman's Brake Lines

Please! If you have any doubt as to your ability to make your own brake lines, DON'T EVEN TRY! Your life, your familys life, or someone you don't even know could suffer the consequences! Just contact Rainman!

Another site that makes brake line sets, though they are not as accurate as Rainmans, is Classis Tube

They also carry the 10mm x 1.0 flare nuts (Part # ST8036), and the 3/16 brake line in 25' rolls (Part # C3). Plus they have all kinds of clips, and other often needed brake items.

I'm not going to give a step by step, how to pull, bend, and replace your lines, but I am going to go step by step, and show you how to do the hardest part of this job: Double Flaring!

Tools needed:

Double Flaring tool. I bought a cheap flaring kit from Auto Zone. It came with the split die block (cheap ass piece of junk) , a set of dies to make the double flare, and the yoke that makes the 45 degree flare. I threw the die block and yoke assembly away after just one attempt! The die block allowed the tube to slip resulting in bad flares. I replaced those two pieces with Imperial brand pieces from a PLUMBING flare kit I've had for years. The Imperial split die block has knurled holes in the die block that really grip the tube preventing slippage, double clamps (one at each end of the die block), and the yoke is massive compared to the Auto Zone junk. I then used the dies that came with the Auto Zone kit.

Tubing bender: Some will claim to never use one, but it sure makes pretty bends once you get the hang of it. Cheaper styles will only bend to maybe 120 degrees. The better ones will have a degree scale and bend a true 180 degrees, and will have different dies for various size tubes.

Metric flare wrenches. Craftsman makes a good set. The flare nuts fittings take a 10mm wrench. You might also need a propane torch to get some of the fittings loose and a good set of Vise grips for the ones that won't come off easily!

Tubing Cutter or fine blade hack saw. It is very important to get a STRAIGHT cut on the end of the line. I prefer a small tubing cutter like plumbers use. It automatically makes straight cuts, is super quick, and you don't run the risk of collapsing the tube trying to clamp it in a vise to cut it.


If you are not doing a frame off, work on ONE line at a time. It's fine to pull all the lines off at once as long as you know where they go. Masking tape and a black marker are your friends! Take pics and pay attention to how lines are attached to the frame or supported on the tub before removing. If your lines are all original don't sweat trying to make an exact duplicate! There may be Bezel Police ready to slam you, but I'm not aware of brake line police!

Just make sure to get the line routed so it does not touch anything except the clamps holding it. A line that is touching something will eventually wear through due to vibration. Small sections of rubber hose can be slit and placed over the line to help protect it if it must touch something to be routed.

I always leave a couple of extra inches of brake line at each end for mistakes in flaring. It pisses me off to spend an hour bending up a line to the exact shape, screw up the flare, and not have enough line to cut it off and do another one. Also it can be hard to get the tubing cutter on the end if the bend is tight.

Practice, practice practice! Get some old line and practice making the flares BEFORE trying it on your actual lines!

Preparing the Tubing...

Ok.  You have your new 10mm x 1.0 fittings, a new flaring tool, and you just completed the most beautiful and complicated bend job in the world. Now, how do you get those nice double flares on the ends? You have to prepare the tubing first by cutting it properly.

The objective of cutting tubing is to produce a square end that is free from burrs. A lopsided cut will make a lopsided flare! Some folks use a hacksaw to do it but I prefer a tubing cutter.

Tip: A convenient method for cutting tubing with a hacksaw is to place the tube in the flaring block and clamp the block in a vice. Use the clamp block as a guide for the hack saw blade to get a square cut. After cutting the tubing with a hacksaw, remove all saw marks by filing the end, or sanding it square.

Tubing Cutter

Fig. 1

Tubing Cutter

Using Cutter

Fig. 2

Using Cutter

Square Cut

Fig. 3

Cut tube

Better Cut

Fig. 4

Another Cut

Using the tubing cutter...

A tubing cutter is basically a clamp with two rollers on one end, and a hardened steel cutting wheel on the other end. See Fig. 1 . I use a small plumbers cutter. The smaller cutters will work better on 3/16" brake line.

  1. Turn the tubing cutter knob counter-clockwise to move the double rollers back away from the cutting wheel until you can wrap it around the brake line. Place the tube in the cutter with the cutting wheel at the point where the  cut is to be made.  
  2. Turn the knob clockwise to tighten the tubing between the rollers until it's just touching the tubing. Too  much  pressure  applied  to  the  cutting wheel at one time may deform the tubing or cause excessive  burrs. Refer to Fig. 2.
  3. Rotate the whole tubing cutter clockwise ( toward  its  open side ) around the tubing until there is a noticeable ease of rotation. You will see a score on the tubing. Refer to Fig. 2.
  4. Tighten the roller adjustment knob, just a little bit.
  5. Rotate the tubing cutter around the tubing again until there is a noticeable ease of rotation. The score on the tubing should be deeper. Tighten the roller adjustment knob again.
  6. Keep going around the tubing and tightening the rollers when there is a noticeable ease of rotation. You'll see the score or the cut beginning to deepen. Keep going until the brake line separates. The piece you're cutting just pops off.
  7. After the tubing is cut, remove all burrs and sharp edges from inside and outside of the tube  with  deburring  tools or sand paper. That's what the pointed deburring point (spear) on the side of the tubing cutter is for. Stick it inside the brake line and gently twist it a few times. Don't ream the tubing out! This will make a thin weak area! Just get the burrs off! See Fig. 3-4.
  8. Blow  out  the tubing with compressed air.  Make  sure  no  foreign  particles  remain!



Tube  flaring  is  a  method  of  forming  the  end of a tube into a funnel shape so it can be held by a threaded fitting called a flare nut. There are two types of flares, single flares used in low pressure situations like fuel line, and double flares used in high pressure lines like brakes and clutches. Double flaring is nothing more than folding the edge of the hard line back on itself (thereby doubling the thickness at the end) then creating the actual 45 degree flare . This doubling allows the flared end to withstand the higher pressures of braking systems without splitting.

Imperial Tool

Fig. 5

Imperial Split Die Block

Open Clamp

Fig. 6

Open Clamp

Adjusting Height

Fig. 7

Adjusting Height

Die In Place

Fig. 8

Die In Place


Now that the tubing is cut square and de-burred it's time to do the actual flaring.

  1. PLACE THE FLARE NUT ON THE LINE NOW!!! You will be cussing yourself if you don't!
  2. Loosen both die clamps until you can pivot the one clamp to open the block. See Fig. 6. ( Notice anything?....)
  3. Insert the tubing into the 3/16 hole, pivot the end clamp back to lock position then turn the die block so the end of the line is pointing up.
  4. Place the correct die next to the end of the tube as shown in Fig. 7 then adjust the height of the tube to match the die as shown. This is critical! Too much tube sticking up allows the tube to try to collapse on itself when formed or forces the tube to be pushed out of the die block, and too little results in not enough material being bent back on itself to correctly form the double thickness end. FIRMLY tighten the die block clamps! You don't want the tube slipping!
  5. Place a drop of oil on the little rod sticking up from the die. Now flip the die over, and insert it into the end of the tube as shown in Fig. 8. The little rod that goes inside the line prevents the tube from collapsing inwards when you form the end.
  6. Place a drop of oil into the depression on top of the die that the anvil fits into. Attach the anvil to the die block as shown in Fig. 9 and center the tip on the die.
  7. Slowly start tightening the anvil. If the brake tube is being pushed out, the clamps are not tight enough! You will need to start over with step 1! 
  8. Tighten the anvil until the die contacts the die block all the way around. This step rolls the end of the tube back on itself to form the double thick end.
  9. Remove the anvil and die. Inspect the end of the tube. It should look like Fig. 10.
  10. Place a drop of oil on the tip of the anvil. Now reinstall the anvil without the die, and center the tip of the anvil into the end of the tube as shown in Fig. 11.
  11. This step forms the 45 degree flare. SLOWLY tighten the anvil a bit, then back it off to see what is happening. You want to make a good flare, but if you go too far, you will split the edge of the tube. See Fig. 12 for what a good flare should look like. If there are ANY cracks or splits around the edge of the tube, then start over!

Step One

Fig. 9

Step One

Result of Step One

Fig. 10

Result of Step One

Step Two

Fig. 11

Step 2

Double Flare

Fig. 12

Finished Flare!


  1. You did put the flare nut on the line before all this.... right?.... Of course you didn't, just like I didn't for this line...:-)


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