One of the first DIY automotive repair tasks that I took as a teenager was a brake caliper replacement. I had a harrowing moment, where the brake line nut seized, and I thought that I might be ruining new brake lines. Thankfully, disaster was averted, and I didn’t have to do my first brake line flare until much later.
The trick with these brake line flaring kits is to get all of the parts lined up properly. If you don’t, you can create a crooked flute, and then nothing connects and seals properly. Brake lines have 1200+ PSI, so there isn’t a lot of forgiveness for shoddy work.
Ideally, you can flare your brake lines before mounting them onto the car with a vise-mounted flare kit. However, life is rarely ideal, and every time I’ve had to flare a brake line, it is because someone ruined it while trying to take it off of the caliper. As a result, I’m a fan of the kits that allow you to perform the flare while the line is still on the car.
The other thing is that flaring a brake line is one of those jobs that you hope to only do once in a while. As a result, you’ll be tempted to go for the cheapest flare tool.
Going for the less expensive option will inevitably lead to poor flares and hours of extra work as you cut and re-flare the line, trying to get a perfect, non-leaking seal. It’s worth spending the extra $40 or so to get a tool that will do the job correctly the first time. After all, you are already saving hundreds of dollars by performing the job yourself. What is an extra $30 on a better quality tool?
Cheap Flare Tools
The most common flare tools are the ones that have a holding device for the line, and a small punch that creates the flared end.
The challenge is that this punch will “swim around” and that getting a perfectly aligned flute is almost impossible.
This list is going to offer a list of better-quality tools that will allow you to create a perfect flare.
That said, my very first flare jobs were with something similar to the OTC 4503. It wasn’t a pretty job, and I spend nearly an hour on each end, cutting, deburring, flaring, testing, and then redoing the entire thing. The bad thing was, the brakes on that car were always a little spongy, and we could never find where the air was getting in (even after replacing the master brake cylinder). I like to use a better-quality kit in order to get the job done quickly and correctly.
You will need a brake line cutter. This one from Rigid can cut copper aluminum, brass, and plastic. It is tiny enough that you can fit it into the most impossible places, and the finished cut tends to be super-clean with hardly any burr.
It’s one of those tools that is so quick and fun to use that you may find all of the other mechanics in the shop trying to “borrow” it from you.
It also sets you up for success since you can start with a clean, level cut for your brake line before you begin the flaring process. Add a dab of oil before you cut to help get a smooth, even cut.
When you cut your line, it will compress the metal slightly. Before flaring, use a cone file or the deburring tool recommended below to open it up and remove any loose metal.
Best Brake Flaring Tools
MASTERCOOL Hydraulic Flaring Tool Kit
Professional mechanic shops need the best flaring tool that will do everything from HVAC air conditioner lines to transmission lines. Brass tubing, copper tubing, soft steel brake line, heavy steel lines… this one does it all.
This hydraulic tube and die set is unlike any others that we have reviewed. It is a next-level tool that is engineered to provide a factory-grade professional finish every time.
The first unique feature is the magnetic die holder. The magnetic attraction allows you to slip a die in place easily. It also allows you to work with that die without it sliding around as you feed the tubing into it. This feature greatly speeds up one-handed operation.
Once you get the tube into the edge of the die, you can tighten it to secure the tube into place. Then, as with the other tools, you add the correct punch bit. A few screws of the handle will have the punch seated properly, and then you can pump the lever to activate the hydraulic press, creating a perfect finish.
You don’t need to mount this into a vice, so it works well both for brand new custom work or for fixing a line that is still mounted to the car.
You have an unlimited number of dies and punches, so you shouldn’t ever need to purchase another part even if you are doing fuel lines or transmission lines. It even creates push connect lines and 45-degree flares!
Bubble flaring is one of the most challenging maneuvers to master. If you do a lot of work on BMW and other European imports, you’ll appreciate how much easier this tool makes it.
It also includes the Mastercool tube cutter, so you don’t need to buy that separately.
This hydraulic flaring tool is designed for the high-tempo shop and should last for decades of regular use. It has a one year warranty on the hydraulic yoke and a 90-day warranty on the dies and parts.
the Mastercool is a heavy-duty model that is fairly common to see in an ACE certified shop, but the price keeps it from being commonly used by the shade-tree mechanic. The only downside is that it doesn’t fit into tight spaces as easily.
Vice Mounted TGR Brake Line Flaring Tool
This vice-mounted model is a staple for the professional shop. Whether you need to flare transmission lines or just get those old steel lines going again, this tool will do it all.
This is a vice-mounted flare, which means you need to remove the pipe and carry it to your workbench to do the flaring work.
With the TGR, you are getting the ultimate tool. It does single flares, double flares, and bubble flares. It also has four different size dies so that you can do 3/16″ brake lines, 1/4″, 5/16″ and 3/8″ tubing. Basically, there isn’t a car line that you can’t flare.
Eastwood makes a similar model but at a much higher price. The dies from Eastwood seem to be compatible with the TGR and can be purchased separately if you are trying to work on a more esoteric project.
The T-lever on the end is what sets this tool apart. With this design, you have plenty of leverage to create a quick, even, flare with just a smooth press of the lever. This helps to prevent you from cracking the flared end, while also delivering the fastest finished product.
If you are running a new brake line and have more than four flares that you need to create, this flaring tool kit is worth the money.
Eastwood On The Car Double Flaring Tool
This Eastwood tool is a dream come true for anyone who finds themselves working on a lot of old cars.
The 3/16″ SAE die is identical to the ones that are vice-mounted. The only difference is that a removable handle has been installed, so you can use it while the brake line is still on the car.
It works great on all metal types and is one of the best for flaring copper.
The other nice feature is that it is extremely compact. This makes it easier to fit the tool into all of the tight areas around the brake caliper.
With most of these tools, you need about 1.5 inches of straight brake tubing in order to fit it into the die. If the line is slightly bent, sometimes you can force it into the die and get it to straighten out. Or use some tubing pliers to straighten it.
That said, these longer dies create a much more professional finished product.
This kit is designed to do a double flare. The process looks like this:
- Step 1: Cut the line, so you have a smooth end to work with.
- Step 2: Straighten the line so that the die can slide on.
- Step 3: Add your retaining nut (you can’t get it on after the flare is completed)
- Step 4: Put the die on and use the positioning bolt to ensure the line is flush. Tighten the die to secure the line in place.
- Step 5: Tighten the OP1 tip into the die to create the first flare.
- Step 6: Tighten the OP2 tip into the die to fold the metal back for the second flare.
The benefit is that you are getting the Eastwood brand quality in a tiny tool that will fit into any space. The downside is that this tool is much slower than many of the other options that are here. However, for the home mechanic, it is probably the best brake flaring tool.
Rigid Brake Line Flaring Tool
This is the design that I like the least. It has the multi-size clamp bar in place of a die set, and then the clamp goes over the line and tightens the punch into it. However, this is a high-quality version that seems to work quite well.
I’ve never had as much luck with creating consistent flares with this design as I have with the Eastwood tool.
That said, I have never used the Rigid flaring toolset.
It is designed for mechanics who may have a wide variety of brake line tubing (both SAE and Metric) that they need to work on, but who don’t want to spring the big bucks for the Mastercool.
And, the design is simple. After clamping the “die” over the tubing, you simply tighten the punch, and you are done. The wing nut for tightening the punch is ergonomically friendly and easy to use. Additionally, this model comes with an adapter for your cordless drill so you can get your work done faster.
Most of the cheap Harbor Freight-type models are using a similar design to this one. However, the Rigid design is a world apart in that the metal is better quality, the tolerances are tighter, and the tool doesn’t work anything like the other cheap knock offs.
As far as a non-hydraulic press, this one is quite efficient. However, if you are struggling with arthritis or lack of hand power, then you definitely need the cordless drill attachment.
Eastwood Deburring Tool
As you cut these lines, you are going to leave tiny bits of ragged metal on the edges. It is important to remove these pieces of metal, so they don’t break off inside the line and cause more damage. Additionally, you want a smooth, clean, seal, and that can only be done if you have a smooth flared edge to work with.
This adjustable deburring tool is a nice add-on to have. It allows you to clean the inside of a line with the pointed end, and then the opposite side is designed to clean the wider edge of a flared tube.
A tool like this costs a little more but quickly pays for itself in helping you keep metal shrapnel from entering the line.
Common Types Of Brake Flares
There are four main types of tubing flares that you will run into.
The first is the nearly universal, 45-degree double flare. This is where the tubing is folded over on itself to create a thicker lip that holds up to the higher pressure of brake and clutch lines.
The 37-degree single flare is typically used with the heavy-duty stainless steel automotive brake lines where AN fittings are used. Army Navy fittings are only found on military applications and some street rods and custom jobs.
The bubble flare (sometimes referred to as ISO, DIN, or Metric-Style Flare) is the one that might be the most frustrating to create. It is most commonly found on European imports, although some of the newer domestics have them.
Thankfully, the newest cars use a rubber brake hose that does not need to be flared.