Can someone straighten me out on making bubble flares?

[bunnspecial]

I have been piddling along trying to replace a couple of brake lines. What I need are 3/16" lines, bubble flared with a British Girling flare nuts. I could buy them already made, but what's the fun in that?

The flare nuts are on the way-FedHill sells them.

I've been practicing flares on a piece of line, though, and I'm at a loss. I'm using an HF double flare tool, and realize I probably should go and get a better quality loaner from one of the parts stores.

I've been told that what is initially formed by the die in a double flare kit is a bubble flare, but the problem I'm having is that what I make seems to look nothing like the bubble flares I currently have.

Am I doing something wrong? Do I need a dedicated bubble flare tool? If I do, it seems like something that doesn't really exist...

 

[HangFire]

"Am I doing something wrong?" Yes you're using a double flare kit to try to make a bubble flare. You might succeed in something that looks similar, that's about it.

I use the OTC 6504 bubble flare kit, and have replaced most of the steel brake lines on my old Dakota with bubble flared NiCopp lines. They've been on there a few years now, and I'm still alive.

Which leads me to ask, are you using NiCopp? It is easier to work with.

Another question, are you cutting square ends, deburring, and chamfering?

 

[Spectre694]

I would get a bubble tool if you can but otherwise yes you can make something pretty close to a bubble on a double flare. It isn't 100% the same but it does work. It's definitely kinda of a pain though but there are plenty of YouTube videos showing how to do it.

You do need to flip the bar upside down and can you link the tool you have?

 

[Creekside]

I have been using a Rigid kit that I borrow from work as needed. I had never flared a line before and it worked perfectly on the first try. I would describe it as idiot proof.

 

[kschachn]

I have one like this but there are less expensive non-hydraulic units with the same type of flaring dies. After using a tool like this you'll never wish for the HF type again.

And +5000 on the NiCopp or Cunifer lines. Another thing that will convert you for life.

 

[2EHA]

i remember repairing a brake line on a 74 land rover pickup truck.

the girling flare isn’t the same as the modern bubble, i don’t even know where you’d find an old flaring tool for it. regardless the modern bubble tool seals fine if you use the correct UNF flare nut.

by the 90s everybody switched to the current bubble flares with 10x1 metric nuts.

 

[MadAmos]

Ensuring a square cut and proper deburring are very important.

 

[bunnspecial]

Thanks everyone for all of the tips.

A couple of things:

1. This is the tool I'm using

Harbor Freight Tools – Quality Tools at Discount Prices Since 1977

Harbor Freight buys their top quality tools from the same factories that supply our competitors. We cut out the middleman and pass the savings to you!

www.harborfreight.com

Since posting this, I've actually been able to get a couple of passable flares, so I guess it's capable but it's not easy

2. My procedure has been cut the tubing with a rotary type cutter(and yes, I've been using these for years, mostly on either soft copper or super hard stainless, so I'm acquainted with the tighten a little, spin until it does with no resistance, tighten a little more, spin more, repeat until it cuts through). I've then been putting it flush with the bottom of the block in the tool, filing flat, chamfering to an eyeballed 45º with a file, and finally deburring using the attachment on the cutting tool. Of course then it gets flipped over the "right way" in the block and set to the indicated depth.

3. I emailed Fed-Hill with some questions on this, figuring they were my best bet considering they were the only supplier I could find that actually carried the correct Girling flare nuts. They confirmed that in fact the bubble is different from a Metric/DIN bubble flare and couldn't point me to a tool that can make the exact correct flare. Their best advice was to use Cu-Ni line and a bubble flare tool, and when tightened the metric bubble was close enough and the Cu-Ni soft enough that it would seal. They said the first stage of a double flare would probably work also, but using a bubble die was best.

4. I've been using mild steel line. I'm glad to have practiced with it, but everything I've read has convinced me that Cu-Ni is definitely the right choice.

5. To that point, I went ahead and bought 12ft of line form Fed-Hill, and was able to rent a really nice $350 tool(that they also sell) from them. Both are on their way.

Hopefully I'll get this wrapped up soon-I want to get this car back on the road, but of course am not about to cut corners since brakes are WAY too important for that.

 

[atikovi]

1. This is the tool I'm using

Harbor Freight Tools – Quality Tools at Discount Prices Since 1977

Harbor Freight buys their top quality tools from the same factories that supply our competitors. We cut out the middleman and pass the savings to you!

www.harborfreight.com

Since posting this, I've actually been able to get a couple of passable flares, so I guess it's capable but it's not easy

Just because they look good doesn't mean they will seal. Had one of those cheaper flare tools when replacing lines on a Ranger. After the 3rd try was leaking as much as the first two, I bought the hydraulic model shown previously. The first flare I made didn't leak at all as well as all subsequent ones.

 

[nobb]

When I was flaring brake lines I was getting super frustrated that I could never get it right no matter what I did. Turns out it was the tool itself. Could never figure out why but I got a higher quality tool set and all of a sudden all flares turned out perfect.

 

[Jake_J]

It is actually possible to make bubble flares using a cheap bar style double flaring tool it just takes some practice. Like others have pointed out preparation is key, use a tubing cutter also make sure to deburr the end. Cu-Ni or NiCopp lines are more forgiving than mild steel, and will compensate for a imperfect flare. They also make cheap bar style ISO bubble flaring tools which will make it easier, I redid a couple lines for my W123 using a cheap Autocraft bubble flaring tool and they turned out well despite the fact I used PVF coated steel brake tubing.

 

[exranger06]

Part of the problem may or may not be that the wing nuts on the tool might not be tight enough. So when you try to flare the line, the tool just pushes the line through the "bar"instead of flaring the end. Pretty much every time I use my cheap flaring tool, I have to use a pair of channel locks to grab the wing nuts and get enough leverage on them to really tighten the heck out of them. That's the only way to get them tight enough so the line doesn't slip.