Brake line questions

[Drummerdad]

So Im in the middle of modifying Isaacs truck, and Ive got the frame shortened, getting ready to box it, then install the IFS and the 4-link rear. I am so deep in this, there is no reason to put old stuff back in. With the 4 link and the IFS its turning custom very quickly. My question is about the brake lines. If you all could build (or have built) an all new brake line set-up what would you use, and what wouldnt you use?

Ive done a little reading, and it appears the aluminum AN fittings are questionable because of pressure. I would prefer AN fittings, as I am very familiar with them being in aviation. Im afraid that limits me to stainless lines and stainless fittings. The stainless lines are hard to flair properly, and might gaul when assembled. I like the new NiCopp lines, but cant seem to find any information on what fittings to use with them. Everyone says to use "steel" but Im only aware of aluminum and stainless AN fittings. Do they make standard steel? I would think it would rust as well.

What do you all think? Can I use the NiCopp with stainless AN fittings, and be ok? Should I just suck it up, and install the stainless lines and AN fittings?

[Wildergarten]

The big question is whether you care or not about DOT approval. It may matter to your insurer.

The copper-nickel double flare is preferable for anti-corrosion purposes.
The stock steel double flare expands less under pressure.
Stainless braid with stainless AN fittings is an indestructible setup and will be very stiff on the pedal, but unless the lines are coated they don't meet DOT spec. Some local hydraulic system suppliers understand all of those rules and can fab what you need in vinyl coated stainless, but at one hell of a price.

I currently plan to go with the copper-nickel with new steel nuts and the existing brass fittings except at the hose terminations where I'll go to an inverted flare-AN adaptor of some sort. I'll purchase the brake hoses from said outrageous supplier. No matter what the system, the real hassle is bulkhead fittings. The Earl's parts have the correct adaptors in galvanized steel, but they are designed for thinner steel than one finds on these trucks.

[PwrWgnDrvr]

Just get out your angle grinder and make the steel thinner til it fits.....

[Wildergarten]

Just get out your angle grinder and make the steel thinner til it fits.....

I have a parting tool and I know how to use it.

[Kaegi]

I'm with wildergarten. hard to beat double flare and it is also illegal to run anything else on the highway. I don't live in a salty area so always use the US made steel lines. harder to bend but I have a nice tubing bender.
the Balkamp lines at napa that are NOT coated in green are the thick US made steel lines. the green coated Chinese lines they also sell are garbage thin wall and crinkle easy when trying to bend

[Kaegi]

I'm with wildergarten. hard to beat double flare and it is also illegal to run anything else on the highway. I don't live in a salty area so always use the US made steel lines. harder to bend but I have a nice tubing bender.
the Balkamp lines at napa that are NOT coated in green are the thick US made steel lines. the green coated Chinese lines they also sell are garbage thin wall and crinkle easy when trying to bend

edit. the steel lines dont rust really because they are galvanized and the copper nickel don't rust. steel will eventually rust in the east if you drive in winter.
the Steel inverted flare nuts are zinc plated. like was said before. DOT requirement

[Drummerdad]

Thanks for the information guys. I have tried looking for T-DOT (Tennessee dot) restrictions, and I cant find anything for passenger non-commercial vehicles. I have also read a lot of comments about the aluminum AN fittings not being rated high enough, but the information I found on them says the -3 and -4 are rated to 5000 psi. I dont know any more. I hate the double flair/brass fitings style found in factory set ups. I dont think I have ever had one come apart without stripping, breaking or something going wrong. I have had to cut every line off of this parts truck. None of them came off. I deal with AN stuff every day and it works fine. I guess Ill keep looking into it. Maybe even call the DOT and see what they say. I want to be legal and safe, but I dont want to put something on the truck that became a standard because it was economically a better business decision. If it costs twice as much thats fine, as long as it works and I dont have to fight it in the future.

[Wildergarten]

I have tried looking for T-DOT (Tennessee dot) restrictions, and I cant find anything for passenger non-commercial vehicles.

Regulations of this type are Federal, not State.

I have also read a lot of comments about the aluminum AN fittings not being rated high enough, but the information I found on them says the -3 and -4 are rated to 5000 psi.

I've built spacecraft hardware; so I know how you feel. I don't see the problem with pressure ratings either; I do with corrosion and fatigue resistance in an automotive application. A truck is nowhere near as benign an environment as an aircraft from that perspective. Aluminum has no fatigue limit. Stainless flares do crack.

I hate the double flair/brass fitings style found in factory set ups. I dont think I have ever had one come apart without stripping, breaking or something going wrong.

Allow me to offer a trick. First, wiggle the frozen line, get it warm (not hot), use a penetrant and give it 24 hours. While it's wet with the penetrant, take a pair of ViseGrips and squeeze the fitting on each opposing pair of flats. You're not trying to remove it; you are simply flexing it and breaking rust crystals to allow the penetrant to get in there better. Then, after the 24, take a tubing wrench to it and give it a few light taps with a hammer. if it doesn't crack right away or shows any sign of slipping and rounding the nut, put the ViseGrips back on and try those. This method has seldom failed me. I then save the brass and replace the steel. I assume you know and have the tools to make a double flare. If not, Imperial Eastman used to make the best. Don't know now.

I deal with AN stuff every day and it works fine. I guess Ill keep looking into it. Maybe even call the DOT and see what they say. I want to be legal and safe, but I dont want to put something on the truck that became a standard because it was economically a better business decision. If it costs twice as much thats fine, as long as it works and I dont have to fight it in the future.

Aircraft have PM procedures to replace all that stuff. Vehicles don't. Insurance companies like things simple. Hence the choices of the regulators. The funny part is that a double flare in steel is just as tricky as an AN flare is in stainless. I actually made a setup for a lathe with an aluminum block with ball bearings in it to hold a shaft with a hardened cone for the flare and a mating aluminum collet with a countersink to hold the tube in the chuck. Worked great.

BTW, stainless Swageloks and MS flareless fittings are good too. Legal they're not.

Mark

[Drummerdad]

Thats a valid point about preventive maintenance. And thinking about it, the truck wont be in snow anymore, or rain if I can help it. I plan on driving it, but not depending on it for daily transportation. Itll be stored for winter, so maybe the lines will fair better. I guess Ill buy a double flair tool, get the Nicopp lines and steel fittings and suck it up. Thanks guys.