Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Bralke line nut - Toyota

I want to change the flexible rear brake hose on my '79 Toyota Celica. A few weeks ago, I flushed out the system and noticed some seeping at the hose. Since the hose is 15 years old, time to change.
Anyway, I started to turn the brake line nut (with a 10mm line wrench) but the nut is stubborn. I certainly don’t want to round the corners One corner is already rounded. I sprayed the nut with PB blaster.No luck.

I’ve heard of tricks such as Using a frozen (cold) line wrench for a better grip (metal contracts), using a torch to expand the nut, etc. A new hard line is NOT available, so I don’t want to damage it.

Time to give the car in? I like saving money, but I don’t want to damage anything either. I replaced the master cylinder myself seven years ago, without any problems. I can’t figure why the same type of fitting would give me problems (corrosion?)

Last person to work on this part was at a Toyota dealer. That was in the days when I thought installing an alternator was high adventure.

Since the nut is part of the hose,

I’d get on it with a pair of Vice-Grips clamped really tight.



I usually cut the hose off… it will be much easier to unfasten. Get your other hose ready because you will loose a fair amount of brake fluid.

The nut in question is on the rigid line, not the brake hose. Should I still use vice grips on it?

If a line wrench isn’t working, what else are you going to use?


Do this a few times. Tap on the fitting. Repeat. Let it soak overnight. Repeat. A vice grips on it and another on its fitting mean you can apply major torque, but some back and forth wiggling may be all that’s needed after soaking and tapping.

1 Like

No, not if there is any other way. Vice grips will distort the nut onto an out of round and you may never get it off or a new one on. I’d use a nut cracker or die grinder first being very careful not damage the inner threads. But first I’d cut the hose and use a box end wrench, a good quality one, six sided with the relief notches in it.

I’ll let the PB Blaster soak in for a day-or two.!
Shanonia" I’ll also try tapping it a few times.

What I WON’T do is to apply too much pressure with my line wrench and strip the nut. The line wrench is made by “Performance Tools”. Don’t know about the quality of this. Failing all that, I’ll just take the car to a shop (before I do any damage).

I certainly don’t want to make a mess of things, and then present the car to a shop and effectively say: “Can you clean up the poop that I made!”. My pride may get hurt (this is one of the few jobs I could not do myself on this car- a car practically made for DIY repair.)

1 Like

Good point, Tester. I’ll see what the PB Blaster can do overnight. If it doesn’t work- time to call in a pro!

1 Like


I also have gotten a few of these impossibly stuck flare nuts off with vice-grips and PB Blaster. Even nuts that my flare wrenches tried to round off.

I will ask, though, why can’t the nut be replaced if you damage it? If you totally bork the nut with the vice grips there is usually enough hard line to cut off the nut, slip a new one on and re-flare the end.

Not sure if these use invert flare or bubble flare but I’d guess the nut is metric and they are available. Tools can be rented or even purchased fairly cheaply.

I’ve never had to use a flaring tool, and would be skeptical about my ability to put things back together should I have to replace the end. Last thing I want to do is get towed to a shop, who may be reluctant to clean up my mess. But, if all things fail, a new end will have to be put on. That is one long brake tube (goes right to the proportioning valve), after several neatly formed bends.

Sounds like you may be the get in and do it kinda guy. If you were to go online and learn the different types of flares and their applications, it might serve you well in the future. Double flares are commonly used on brake lines. If you buy some brake line and a decent flaring tool kit you can take some time and practice making flares. But never brake lines unless you are completely confident in your work. Practice in this area is the best way to learn.

I’m thinking that all the OP needs is this tool shown in the video I provided.


Surprised no one has suggested a flare wrench

A quality line wrench can make a big difference, I have observed the difference between Craftsman and Snap-on line wrenches in use but I don’t expect a DIY person to buy Snap-On tools.

I have had success with using a vise grip over a line wrench to “tighten” it on the nut.

That’s what the OP was using.

“10mm line wrench” is his name for this tool (see first post.)

I know Snap-on uses the “flank drive” trademarked name to grab the sides of the fastener, not the corners, supposedly preventing the corners from being rounded off, while at the same time getting a better bite.

I kind of doubt “Performance Tools” is using that approach . . .