I've forgotten how to flare a brake line

Could someone give me a few pointers on how to properly execute a 3/16 double flare for brake line?

I've been fighting with it the last two days, some under the car and some on the bench and the results have been dismal and I'm getting tired of making the same mistake over and over again. I'm using the standard issue Autozone brake flaring kit, held in the vise for pieces I can do off the car.

In my experience re-flaring stock (aluminum?) line with the cheap tools is hard to impossible.

Grab some nickel-copper line and try with that first.

The first thing you need is a clean, square cut end of the tube. Just using a tubing cutter and calling it done will net you nothing but grief. I file the end of the tube square, I also run a drill bit the size of the I.D. of the tubing to remove burrs and then file a very slight chamfer on the outside edge of the tube to help the tube to form the first step of the double flare process.

Even when I did all this my success rate was only 50%. It wasn't until I got a MasterCool flaring kit was I able to get near 100% success. Best money I ever spend on a tool.

Not sure of the tool you are using but I have a blue point hand operated one. First off properly cut the line. A tubing cutter is your best friend. The cut needs to be square to the tube. Get this wrong and you will never get a good double flair. Ned step is placing the tube in the clamp. You want the end being flair sticking out on the side of the clamp that has the holes with beveled edges. Now you have to get the tube so it is sticking out the proper distance. You take the die that is stamped with the corresponding tube size and place it flat on the clamp next to the tube. Looking at the side of die you will see a band in the casting. You want the tube sticking out of the clamp the same distance as the depth of the band on the die. Get this lined up and then tighten the clamp. My set has a rod that is used on the press part of the set. Use this to tighten the wing nuts on the clamp. If it is not tight enough the tube will slip when you are making the flairs and not work.

Now that the tube is secure flit the die over and place the stub end in the tube. Place the press over it engaging it with the clamp and tighten the press until the die is in contact with the clamp. Loosen the clamp and remove the die. The press should have a pointed end that you now place where the die was and you again tighten the press with it Engadget to the clamp. It is key that the keep the press at a 90 dog angle to the clamp when you tighten it. I typically press it in until the metal is firmly flattened and you have something that looks like a mini funnel. You ate done.

I can not stress enough how critical it is to get a square cut on the tube and taking the time to clean up the edges after the cut with a file to get any burrs off. The next important part is getting the correct amount of tube sticking out. The rest is easy. Oh I forgot to mention that if you only perform the first part of pressing the die into the tube and stop there you have a bubble flair.

Now that I wrote all this I should make a how to on this with photos or a video.

The chinese tools are almost useless. You need very good accuracy and tolerances for the second flare and they are too poorly made.

I concur with the above - a crap tool is nothing but frustration. And the Autozone tools are crap, even if they look like the good ones.

Proper line prep is important - a straight cut and clean inner and outer diameters. Most pipe cutters have a V shaped tool that's used to clean up the inside quickly and easily.

Stock lines on a Miata are super-hard to flare, I don't know what the material is but it's HARD. I wouldn't be surprised if this was true for most other OE applications. Aftermarket line is a lot easier to work with.

I've always had 100%, effective, and cheap success by completely replacing the line with one I can bend up. Between the giant, premade, straight tubes at Vatozone, and the millions of brake line adapters, I have never had to flare a brake line ever. And it's always been successful. I mean, really, how often are you replacing brake hardlines? That why I can't justify the expensive tools. But, I also don't swap cars like some guys, I keep the same crap until it's finished.

Trackmouse wrote: I've always had 100%, effective, and cheap success by completely replacing the line with one I can bend up. Between the giant, premade, straight tubes at Vatozone, and the millions of brake line adapters, I have never had to flare a brake line ever. And it's always been successful. I mean, really, how often are you replacing brake hardlines? That why I can't justify the expensive tools. But, I also don't swap cars like some guys, I keep the same crap until it's finished.

i flare my own in most cases because i dislike adding adapters and other extra leak prone areas. The biggest trick to flaring your own line is well covered here, just make sure everythings square!

So if I am picking this us right, I need a square cut, right?

The only thing I have to add to what's been posted already is that when you can you should blow out the completed line. Those filings from cutting and cleaning the end of the line are not good for seals.

Okay, I have what I think is a silver bullet for this job. I bought it from Eastwood for $25 or so. Looks like it's out of stock now, I hope it's not gone permanently. Deburring tool

I cut the line with whatever rotary tubing cutter is lying around, as long as it's still pretty sharp. Then de-burr it with the Eastwood tool. After that, I can take a $30 OTC flare kit, using light oil on the die, and get 100% working double flare or metric/bubble flare joints time after time. No talent required.

This is the Blue-point kit I have. It looks like this kit is missing one of the dies as there should be the same number of dies as there are holes in the clamp.

It looks simple and there are many cheap ones out there that look the same BUT what counts is the machining tolerances of all the components and the type of steal that is used. Especially the clamp. I think this is around $100 or so these days new. I have seen them used for $60-$75

EDIT: This one pictured is also missing the steel rod that is about 6" ling that you put in to the hole on the press and you use ti tighten the wing nuts on the press.

Here is what looks to e a complete kit.

Note that the rod is bent in the press. Yes, you do need a lot of force to make good flairs, especially on OE lines. I concur what Keith said the OE lines are a SOB to work with.

Regarding using pre-made up lines. there is a time and a place for them, however, I have found that in many cars and trucks there are different ends on the same line. GMC, in particular, is a real PITA about this. They mix and match fittings on the lines. I just did the line on my GMC truck from the abs motor to the rear flex line. It uses a standard fitting for 1/4 inch line but the one at the flex line is a metric fitting that would normally be on a 3/16 line. I will not use adaptors in brake systems. It is a safety issue. You want to have as few connections as possible. Also in most Sierra and Silverado and Hummers, there is absolutely no room around the ABS motor. You can barely get the line in there never mind adding an adapter so some sort. Same goes for the rear flex line. It is located with the fitting facing up towards the bed so putting an adapter in there and then trying to get a line in there and make a bend so it does not rub the bed is going to be lots of fun. Instead, I just went and got 25' of the Nicoper line and salvaged the fitting off the old line. Snaked the new nicoper line where the old one went and did new double flairs. So I have a one piece line running from the ABS back to the rear flex line at the axle. The total line length is 127 inches or 10 1/2 feet +/- You can not purchase straight lines in that length so you have to make your own.

A tip for anyone doing lines on sierra / Silverado 1500/2500's Do the bed tilt trick that is the same used for the replacement of the fuel pump. IT makes this much easier and it is only 4 bolts out and loosening 4 others and three screws to lift the bed up so you can get access to the top of the frame where the old line runs. It also lets you properly place the line as it goes under the back of the cab. If you get it wrong and the line is rubbing on something you will be doing the job over in short order.

jimbbski wrote: It wasn't until I got a MasterCool flaring kit was I able to get near 100% success. Best money I ever spend on a tool.

I see they offer a bunch of different kits, What kit do you have? Is there a different one you would have picked up in stead of this one?

MulletTruck wrote:

jimbbski wrote: It wasn't until I got a MasterCool flaring kit was I able to get near 100% success. Best money I ever spend on a tool.

I see they offer a bunch of different kits, What kit do you have? Is there a different one you would have picked up in stead of this one?

It depends on what you want to do or need. The kit I have I got from Eastwood when they discontinued selling the Mastercool brand. I can do both SAE and Metric brake lines or flare tubing up to 3/8. I can also so the crimp for fuel lines. I later got the dies to do A/N flares (37 deg.) I don't use it that much but when I can flare a line the first time, every time, I feel it was money well spent. Just the fact that I don't have to experience the frustration when an attempted flare goes bad makes it worth it.

Thanks, From what I figure the http://www.mastercool.com/product/70092/ is what I will grab. I can always add on the Metric sizes if I ever need them. I guess I should check and see what a 94 Mustang has, The rest of my system in 70 Eldorado so doubt that is metric.

jimbbski wrote:

MulletTruck wrote:

jimbbski wrote: It wasn't until I got a MasterCool flaring kit was I able to get near 100% success. Best money I ever spend on a tool.

I see they offer a bunch of different kits, What kit do you have? Is there a different one you would have picked up in stead of this one?

It depends on what you want to do or need. The kit I have I got from Eastwood when they discontinued selling the Mastercool brand. I can do both SAE and Metric brake lines or flare tubing up to 3/8. I can also so the crimp for fuel lines. I later got the dies to do A/N flares (37 deg.) I don't use it that much but when I can flare a line the first time, every time, I feel it was money well spent. Just the fact that I don't have to experience the frustration when an attempted flare goes bad makes it worth it.

The other problem with pre-made lines is being either four inches too short or two feet too long. You can't make loops everywhere.

Thanks for all the tips guys. I've been using some of them like dressing the end of the cut tube, but I think I want to try a different tool. Since I rarely do a size other than 3/16 I was curious if this other style of flaring tool has any good reviews? Its new to me, but I found it browsing around last night.

http://www.eastwood.com/eastwood-on-car-flaring-tool-for-3-16-tubing.html

For the price, I would try it. To me it looks like it would be easier to work with in very tight spots.

But for the same money, I've never made a leaky flare with this $29 OTC Stinger tool

I've had the same experience with their metric kit.

By having a metric and and SAE, I can deal with things like Chrysler's tendency to put metric fittings on the ABS pumps and SAE fittings on the soft line attachment points.

Not that adapters bother me either. If they're port to port and properly tightened down, they are no more risky than the existing connections at the ends of the lines.

What I don't understand is people who use compression fittings. Yikes.

I had one of the bluepoint flaring tools. It worked OK (better than the HF ones), but wasn't great.

The Eastwood tool, OTOH, is freaking awesome. Not cheap, but it works very very well.

http://www.eastwood.com/professional-brake-tubing-flaring-tool.html