Flaring brake lines

[scowser]

The trick to getting a perfect flare is to start with a perfect 45 degree chamfer around the outside lip of the line. It takes a bit of time and you have to be very patient, but it's not too difficult when the brake line is off the car, and you can turn it around in your hand and work it from every direction.

Sometimes though you have to repair a brake line already installed and up against the underside of the car. Often it's not feasible to remove the brake line to repair it, because it's convoluted and was installed before the body was dropped onto the frame. This makes it quite difficult to get a good chamfer that's the same all the way around. It's also very difficult to even see the side that's up against the floor.

Do you know of a chamfer tool for brake lines? I visualise something like a Dremel stone, with a 45 degree internal cone on the face away from the Dremel, to grind the chamfer, and with a pin sticking out of the middle of the cone, so the pin inserts into the pipe to properly sit the stone against the line and hold everything steady. This will keep the chamfer same angle all the way around as you spin it This would also save a lot of time for chamfering lines off the car.

Do you know of such a tool or similar device?

 

[Action]

Never grind a brake line. Ever.
Small bits of debris get into the line and that will cause a leak in a rubber seal.
Either replace the entire line (recommended) or make a repair with a double flare.

Bendable (by hand) brake line is now available. For $20 you can buy 25 feet of 3/16 line and 16 fittings via Amazon.

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[scowser]

Thank-you for your reply.

Concerning bits getting into the system, isn't the situation the same, whether it's bits from a grinder or bits of metal from a file? No matter how you chamfer it, you're still going to get bits that you have to remove.

I agree that it's best to replace the whole line, if possible, but a repair with a double flare still needs to be chamfered first. And that's the problem I'm trying to find a tool for. Getting a good chamfer, equal all the way around when your access is severely limited.


I also use the Cunifer brake line. It's fantastic and doesn't rust. It's easy to bend and doesn't kink unless you deliberately abuse it. I think it's most irresponsible for the manufacturers not to use such a product instead of the steel lines they use and which rust out.

Your excellent input is always very much appreciated. Thank-you.

 

[Action]

You are correct. Do not grind or use a file or saw to cut a line. All of those create small metal pieces that are a problem.

Use a line cutter.
Then for the end use a flaring tool.


Manufacturers use rigid steel line because it is pretty durable and cheap. The process is tailored for mass manufacturing. As long as the vehicle is reasonably cleaned the steel line will last many decades. (Accumulated dirt is the enemy) Field repairs are different. Replace damaged line from existing fitting to existing fitting. Hand bendable brake line is easily available. More expensive in bulk than steel. But the consumer is only repairing one car not millions.


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