Flare brake lines? (2023 Update)

I wouldn't splice into the existing brake line, on the general principle that if it broke once, it'll break again. If you can replace the whole thing in sections, with all new pieces, yourself, without major disassembly, then that's to be contemplated.

brakes = safety item safety item = don't mess around

HAH! This IS the "net". Do you (necessarily) expect any better advice here than you'd get elsewhere on the net?

(This is not to criticize anyone's advice... only to point out that this is just as unreliable a resource as anything else you might pick up on "the net")

HAH! LLoyd

Unless you've been watching the group, and you have a notion of who's full of BS and who isn't. Strangely, must of the folks who answer questions here give pretty good advise, IMHO.

When I ask for advice on the net I generally pay attention to all of it, but only follow the bits that make sense after I think about them a bit.

Here's the best, which I think you posted: Don't screw with brake lines. Do not splice brake lines. Do not jury-rig brake lines.

If you had an accident and they found out you'd done something like that, I doubt if the insurance company would pay.

Buy several shorter pre-made lengths and double flare unions to join them. Work from both ends to the middle, and then you only need to cut and reflare, at most, one end of one piece.

If it only rusted under one clip, you may get lucky and be able to cut the line in a solid location, install a flare nut and flare the end of the existing tube , then connect a replacement line from there to the end.

On Hondas and Toyotas it is not uncommon to see a perfectly solid line rot out under a retaining clip (holds line to body) and the rest of the line is perfect.. In this case, installing a short section can be effective and perfectly acceptable. Just make sure the line IS solid, and make sure you do a good jog ov double flaring the line, and supporting the repaired section when you are done. Generally a good idea to replace the entire run that is clipped to the floor - but you can sometimes avoid having to do the twisties on the firewall and around the rear suspension - or at least the twisties up on the firewall/inner fender behind the engine.

Is standard hardware made for the purpose considered jury-rigging?

Today I got a quote of $500 to replace both rear lines with copper-nickel which is flexible enough to thread through the tight gaps where the factory lines go. Does anyone have experience with it?

"Copper brake lines are not advised, but Copper-Nickel hybrid lines are available that won't corrode and will bend easier than mild or stainless steel lines."

-jsw

Actually, I didn't say "don't screw with it". I said don't splice to a known-bad brake line. If the OP can use approved aftermarket components (i.e., brake lines and blocks from the auto parts store) to do the job, more power to him.

I suppose I might think differently if he does it up out of 64 3" sections of line, with 63 splice blocks -- but replacing one 16' long line with two

8' lines makes perfect sense to me.

I suppose that if there's some clearly obvious section that is rotted out for some clearly obvious reason, that would make sense. I'd inspect those remaining bits of line damned carefully, though.

The lines run from front to rear through a slotted plastic shield under the body. I sprayed LPS-3 into it and the visible sections still have their factory green finish. There's a little corrosion where the retaining clips blocked the spray but the only serious rust is at the rear behind a solid part of the shield.

-jsw

Jim - one possibility: go to a local auto parts dealer that sells "Haynes Repair Manuals" and get a copy for your car. The section labeled "hoses & lines, inspection and replacement" should provide useful data.

Hul

Jim Wilk> A 3/16" (0.191") brake line on my Honda rusted through from the

The copper nickel lines are common in europe but almost unheard of here. The copper-nickel alloy used for brake tubing typically contains

10% nickel, with iron and manganese additions of 1.4% and 0.8% respectively. The product conforms to ASTM B466 (American Society for Testing and Materials), which specifies dimensions, tensile strength and yield strength. Formability and internal cleanliness conform to specifications SAE J527, ASTM A254 and SMMT C5B (Society of Motor Manufacturers and Traders). Also, the alloy meets the requirements for pressure containment, fabrication and corrosion resistance for ISO 4038 (International Standards Organization) and SAE J1047. I have used the stuff, and it is easier to use tha steel, and is almost totally corrosion resistant and does not work harden and crack like straight copper. Straight copper is not only "not advised" but is specifically prohibited for automotive brake line use - for very good reason.

The stuff isn't cheap, however. I believe one of the most common names is Cunifer. I see Jeggs is carrying the product now at reasonable prices.

I've seen LOPTS of cases where only a section, or several sections , less than an inch in length are corroded. I have many times replaced only the section of line with corroded spots, saving a LOT of work. Very common, for instance, on 3rd gen Tercels, which have a plastic cover clipped over the lines and salt accumulates around the brake line clips, rotting them through right at the clip.

A local auto store had it on the rack at $30 for a 25' coil of 3/16". NAPA was nearly twice that.

I ordered this to fit the cramped space up beside the gas tank and hopefully do better than the usual cast yoke and 2-bar clamp flaring tool I've been practicing with.

Thanks for the help

-jsw

Rust? Must be the salt. Living in CA, I never saw rusted lines.

Um, ouch. Yeah, pass. ;)

Working with old brake lines is a brass coated bitch. Good luck getting a solid double flare with the now brittle tubing. I much prefer to work with all new tubing. Perhaps look into the possibility of annealing it prior to working with it? I haven't heard of it, but it has been a long while since I was wrenching.

Tips:

Work super clean. Fully steam clean the area prior to working on it. Use flare wrenches only. Dem tings is TIGHT and round off at the slightest provocation.

If you decide to reroute the tube, watch for things like abrading positions, heat from the muffler, rocks from the tires, etc. Shielding and padding are both good workarounds, but some lifts catch different points than you might think, so be aware.

Make sure to use the exact double-flare kit for that line size. I've seen guys try to use SAE tools on Metric lines and fail every time. One guy crimped a line so the flow must have been half what is was. (someone left a note for the service manager) Brakes are a life saver, so I don't fark around.

Before/After photos, please!

Enjoy! This just in via email:

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Makes you wonder why you gave me your email address, huh?

Many imports have bubble flares instead of the double flares common on domestics.

Go get a length of Nicopp or Cunifer (same alloy different companies) It's great stuff, bends easy, flares easy, doesn't rot. It's more money than steel but less than stainless which is a PIA to work with.

Not hard to run the line yourself with this stuff.

OR you could go with the precut sections of steel and just couple them with the correct parts.

Yep, very common for only small areas to rot. GMs like to rot where they tuck the lines in next to the frame because the salt and dirt build up and hold moisture.

I want to know my options before I ask the inspection shop what they will accept, and have several good examples to show them I can do it. They trusted me to replace bad ball joints and brake rotors myself and helped with the Ford's intermittent electrical problem.

It looks like coupling in a new section is possible if I can make good flares in the vehicle's tubing. So far I've made decent practice ones on replacement line with the cuts squared and chamfered in the lathe, to isolate the potential problems. I have a mini tubing cutter that cuts cleanly and will fit the tight space but I don't want to wear it dull. Double flaring is turning out to be tricky and error-prone like welding.

Here's an example of mixed reviews on the next step up in tooling:

The vehicle line is straight for several feet in front of the rust-out, so I could cut out a test section and try different tools and techniques like annealing on it.

-jsw

Cunifer is legal in every state AFIK. It is being used on a lot of the high dollar imports and I've been using it in NY for years, it's in the inspection regs as legal.

Factory line is soft steel tube, I've never had to do anything other than the steps below.

To do a good flare isn't hard IF you follow a few steps.

1 CLEAN the outside of the line. Dirt/rust/crud is not helping. Neither does the coating that some after market line has.

2 cut the tubing square as possible.

3 chamfer it inside and out to eliminate any burrs and clean up the weld seam.

4 REMEMBER TO INSTALL ANY FITTINGS BEFORE YOU ATTEMPT TO FLARE THE LINE!!!!!!!

5 Set up the tool and it's adapter properly.

6 LUBE the line and forming tip.

I've made good flares with just about every flare tool I've ever used. From the cheap chinese ones to my mastercool unit. Some are easier than others but if you do the steps they work.

This is the one in my tool box

It's basically a hydraulic version of the tool you have.