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View Full Version : How to Cut, Flare & Bend Cunifer Brake Line


YellowRose
05-04-2017, 08:30 PM
Our dynamic webmaster, Dave Dare ~ simplyconnected, has just completed a Tech Tip on 'How to Cut, Flare and Bend Cunifer Brake Line'. You will find it located in the TRL in the Brakes & Replacement Hard Lines & Hoses section. Check out the video! Thanks, Dave!

simplyconnected
05-05-2017, 06:14 AM
Thanks for the kudos and for posting the video, Ray. Many of our members have done this disk brake retrofit to their Squarebird and many more are still kicking the idea around before they take the big plunge.

My purpose is to show how easy brake lines are to make and install. For anyone who hasn't done this type of work, it looks very intimidating. I assure you, it is not. Many of the procedures require more effort to explain than to actually do the work. If I get lots of questions, I will remake the video with the answers included.

I like doing brake work because nothing is heavy and the learning curve is very short. By the time you flare your second or third end, 'learning' is in the past.

I break this job into areas: LH Front wheel area, RH front wheel area, proportioning valve/master cylinder area and rear end area.

The tools required are all 'hand tools'. I typically spread cardboard down, lay out my components and tools then I install brake line at a very leisurely pace. Once I'm situated there is no need to get up until that area is finished. All my cutting, flaring and bending is done right then and there. Eg: If I'm at a front wheel that is 'ready' (old parts are removed, rust is removed and the area is painted), I install the components first, then run brake lines TO THEM. (Electrical and plumbing construction is identical, we mount the devices where they belong first, then run wire or pipe to them.)

Is it important to make your lines identical to the originals? Not at all because we are already changing things around. OEM brakes had no combination valve or calipers. We now use two circuits (front & rear) where the OEM ran all the wheel cylinders from one tee and that was universally accepted. We can generally follow the same routes when practical.

Del is starting his brake retrofit very soon. We have members who can answer any of his questions because they finished and their cars are in operation.

I hope the video puts flaring and bending in perspective. It shows how much brake line uses (or shrinks) for the actual inverted flare, it shows how tight a bend can be (the 'stub length') for a 90 degree ell. These are terms commonly used by electricians who bend conduit because the same rules apply regardless of pipe diameter.

If you want to practice bending, use the old line since it will be discarded. Questions? - Dave

del
05-05-2017, 03:11 PM
For those us who haven't recently done any flaring or bending this is super!

simplyconnected
05-05-2017, 09:32 PM
Oh, I forgot to include the 'bending & flaring' link... CLICK HERE (https://www.youtube.com/watch?v=4GAiizhX5HA)

Other YouTube vids talk about which kind of tube, which professional flare and bending tools to use. My vid is about cutting, flaring and bending 3/16" cunifer (copper/nickel/iron) tube using inexpensive hand tools (all of these tools can be found at HF). This size tube is so common, it is also used in metric brake systems. I love cunifer because it's super easy to work with and it will not rust.

CUTTING BRAKE LINE: There is no 'best' method because each has its drawbacks. The most important requirement is a square-cut end. 2nd most important, is to keep debris out of your pipe.

An inexpensive tube cutter produces a square cut, provided the cutting wheel is in decent shape. Rotary cutting wheels do not remove material but they fold the metal 'inward' which closes the hole. The hole must be re-opened and debris removed.

Hack saws can work but are difficult to control without a miter.

Angle grinders are wonderful if kept square.

BENDING BRAKE LINE: A host of benders work, from professional to 'using your hands'. My video shows a pair of $30 bending pliers that I bought before Harbor Freight offered one for ten bucks (now they cost $13). The HF pliers work equally as well as any. Caution: Make sure the jaws match when you look in the hole of the HF pliers. Some folks used a round file to make both sides match. I picked a pair off the shelf that do match.

INVERTED FLARING TOOL: Some kinds of steel are hard to bend. They require 'professional-grade' flaring dies. Cunifer is easy to 'work' so inexpensive flaring tools work just as well.

Bottom line: As shown in the vid, I keep it simple. I use NO power tools (although you can) and my few hand tools are common. Instead of a file, I use a drill bit. I do all my work in 'free air' before assembly so no bench or vise is required.

I use my old line for a few 'tricks':

I cut two 8" lines (with ends) to 'bench bleed' my new M/C. Simply screw the nuts into the M/C and bend the lines back into the reservoirs. Make sure the ends are below the liquid level when bench bleeding.
I measure off and cut a short length 2-7/8" long, from an old line (with the nut). Then, I use that little piece in places where I can't fit a tape measure, like inside a rear wheel cylinder. Eg: I attach one end of my new line to a tee (for example), then measure over to a wheel cylinder WITH my little piece already screwed in. I match the uncut ends, mark my tube and add three inches. This gives me the exact length I need for a finished, flared end.

My methods produce beautiful results with 'exact length' runs and NO 'extra coils' of brake line. This offers your hydraulic system the least resistance for better efficiency, the least flexing and the best operation. Questions? - Dave