Brake line fittings stuck/frozen
 

While inspecting my 72 Trans Am, I noticed my front brake hoses appear original and not in good condition. While trying to replace the hoses, I could not get the line fittings loose. Even using the proper line wrench, the fittings just rounded off to the point they are useless.
I bought new lines from Inline Tube, but I can't get any of the fittings loose on the proportioning valve.

Any tips or tricks to get these fitting loose?

I have had luck "lightly" heating the fittings with a propane torch...slightly tightening them, then loosening, rinse and repeat. A few cycles and they come loose. Avoid twisting the tube once it breaks loose if you plan on reusing the tube/fitting.

george

I'm guessing by "proper line wrench" you mean a flare nut wrench. If that rounded the nut that nut must really be stuck in there. Been there, done that. In that situation I was able to use a vise grip tightly gripped to the nut to bust it loose.

Two methods that work very well if your replacing the steel lines anyway. Method 1: cut the steel lines near the nut. With a combo valve, cut all the lines. Remove combo valve and put in a soft jaw vise. Use a good 6 point socket and long 3/8" ratchet. Flare nuts will come right out. I have a mini-air saw. I can have all the lines cut off in 1 minute. A hack saw will work as well. Method 2: There are 2 places that lock the line to the fitting. 1. Rust between the line and flare nut ID, and 2 compression from flare nut to the valve. Use a pair of high quality vise grips and get them on what's left of the nut as tight as you can. The squeezing of the vise grips will break the seal between the line and nut. They will then turn out. Both methods kill the lines of course, but your throwing them out anyway. Before I begin, I suck out all the brake fluid with a vacuum bleeder. Then the entire repair is no mess, no fuss. If I was trying to save the steel lines and the nuts, then I would use heat. But not in this situation where I am throwing them away. Good luck.

I had a 74 TA rusted bad. I did what Mike suggested for proportion valve. Used some liquid wrench. Good luck. Take your time.

I was not planning on replacing the hard line to the rear brakes, If I could get that fitting loose, I would be ok with cutting the rest off. Good idea on sucking all the fluid out of the system first, that was a mess I was not looking forward to cleaning up!

The line going to the rear is usually a 1/4" line, rather that 3/16" I would be very cautious using heat unless you plan to replace the proportioning valve. It has several rubber seals in it. Heat over 350-400 degrees will likely damage it. You could try a micro-torch right at the flare nut. I would tend to try the vise grips first, before heat. Also, you need a premium flare nut wrench to get really tight fittings loose. Craftsman, Easco, Husky, Kobalt, and the like, probably won't get a really tight line loose. Snap-On is the best flare nut wrench I have ever used, period. Possibly you could borrow one if you don't have one. The others just spread and round the nut when you really apply the torque. Good luck with it.

The first course of action now is PB blaster rust spray , a bit of time and vise grip with good fresh teeth.

If these are original lines probably best to replace them all with stainless lines.

Can't agree more, I have new lines ready to install.

Prebent plated steel lines are what I use for fuel & brake lines. Am beginning to bend & flare ends on all small diam (brake) lines myself as local friend at his NAPA has a large layout table with adjustable pegs & clamps & it makes it quite easy. Also have a bunch of tagged original brake lines from own partscars. Learned my lesson years ago on stainless brake lines, never again, PITA to seat the fittings, doesn't look correct in a serious restoration, & w stainless, just don't need the extra expense. If I was rebuilding a snow plow truck or a Jeep up North, would be a different story, might actually need the stainless construction.

One thing I've done for a long time w integral disc brake proportioning valves, is carefully remove them from firm pedal parts or project cars, then plug the ports with discarded fittings with crimped lines. In my bench vice, next carefully hit them with Forney wire wheel/angle grinder to knock off any dirt & light surface rust. Have to be careful & stay away from the little rubber boot. Next, I store them in sealed large plastic pickle jugs filled with clean DOT3 brake fluid. At one time I had several of these large sealed jugs full of tagged original cast iron integral prop valves. '71-72's, 2nd Gens, & 4 wheel disc T/A-Seville. Hardest part is carefully removing the brake fluid from the full jug, before carefully dropping another valve into the jug. Always keep the jug filled to the lid & sealed tight. Have yet to have a problem reusing such fresh removed integral prop valves.

I had a line stuck not too long ago. I was worried about the open flame/torch and someone told me to use canned air. It's the cans of compressed air for cleaning computers and other electronics. I bought a can at the local office store. Turn the can upside down and spray the nut making sure to use the little plastic tube that comes with it to direct the air...the can puts out some really cold air and will even frost things up. I was very surprised...came right out.

I only use Nicopp for lines anymore, I just got done replacing the OEM lines on my new to me 97 K3500 dually as they popped on the trip from the previous owners house to my house. Of course I had a tow dolly on the back with my GP that I drove up to pickup the truck. I was coming down a hill to a red light that had just changed, an oh s%#t moment. Thank God the tow dolly has surge disc brakes, and I got the rig stopped before the intersection.

I cut the lines and use a good 6 point socket, and heat if your not going to hurt the part you're working on.

Not replacing all the lines now may come back to bite ya in the butt down the road and you'll be kicking yourself for not doing it when you were right there. Too many times I've only replaced the line that was leaking, and have to revisit it again when I left another rusty line on the vehicle, and it failed soon thereafter, not to mention the jeopardy you put yourself in when another line fails.

One other trick on keeping a line wrench from slipping, I put the wrench on and then clamp a pair of vise grips on the outside of the wrench to keep the jaws from spreading, works most of the time if not too much of the outside of the nut has been removed from corrosion.

just did this exact PITA thing last month on my Bird.
PB blaster and vice grips are your friends here. FWIW i ordered my front line kit from https://www.getdiscbrakes.com/
While they are pre-bent I had to do some "above average" TWEEKING to get things lined up to the proportioning valve. NOT BAD but would have been nice to have been a COPY of the original.....THEY ARE NOT. They "coil" portion is way different than original design but still works, just looks cluttered.

I have used a line wrench with vice grips clamping the jaws down so they don't spread. Gives you two handles if you got the room.

I am very leery to use a flame any where near highly flammable brake fluid, so I used punkin's suggestion above and tried a can of compressed air. Put in a longer straw off a can of brake cleaner and flipped it upside down, giving it two blasts. Gave it a couple good tugs with a line wrench and it popped loose! Man what a relief! I will be using this method again!

I've had luck using the smallest pipe wrench you can find, unlike vice grips the harder you pull the tighter it grips.

THIS ^^^^^^^^^^^

I used to use a 5 inch pipe wrench, but somewhere along the line I lost it, and never have replaced it. It was by far the best wrench to get a hold of inverted flare fittings. It didn't matter if it was completely round, the teeth would still get a hold of it and walk it right out. I really need to buy another one of those.

In 50 years of wrenching I never caught any brake fluid on fire, it's not like gasoline, and it can't burn without oxygen inside a sealed system, non issue. As matter of fact in the tech school Midas puts on for training their techs, they show you how to heat brake lines up, and quench them with water to break the rust seal. If a corporate school uses that method, it's probably never going to burn any cars, else they wouldn't be teaching that method.

Quote from the net:

If you get a flex hose fitting too hot, it will blow the line out of the crimp if the system is still sealed due to pressure buildup, it startles you, and it makes a big pop, that's about it though, no fire. Then you have another piece to replace in the system. If the system is open you won't blow the flex hose out of the crimp, only when it's closed, and can build pressure.

I find that the coating on those lines plug up the dies on my hydraulic flare tool after a roll or 2 of it. Yep, I also have a short Rigid pipe wrench. Comes in handy if I remember I have it.

This kicks ass! the fitting will be red hot in seconds, and no flame. https://www.amazon.com/Induction-Fla...NsaWNrPXRydWU=