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Hi everybody,

I really hope this is ok... this is about another Japanese car - but I think this is a universal problem, I would have liked to know about this when I was doing brakes on my Civic, and I've never found a DIY auto repair community that comes close to this one! I went from knowing almost nothing about maintaining my own car to doing ball joints, the oil pan, input shaft bearing, brakes, electrical, all sorts of stuff on my Civic thanks to this community!

I was doing disc brakes at my rear wheels and decided to replace the flex hose, because the fitting at the brake line has really significant corrosion that's caused the rubber boot to expand and puff up. I figured the flex hose fitting is likely weakened, so I'd take 20 minutes and replace the hose. Hah!

The flare nut on the hard line seems to be frozen both to the hard line and to the hose fitting. I started with lots of PB and a flare nut wrench, it rounded the nut. I moved on to flare nut locking pliers (Irwin 4LW, it locks onto the flats and is not supposed to damage the nut), the nut slipped again and rounded some more. I've also taken a propane torch to it, and a few taps from a hammer. Hasn't budged, and now I have a partially rounded flare nut.

I can't think of anything else I can do to free up the nut, so that's question 1 - is there any way to salvage this hard line and fitting? (Someone suggested an air hammer to try to free it up, for example?)

Question 2 is, if I've messed it up completely, can I splice a new line in? The line is coated in some kind of rigid plastic. I only have the little bit you can see in the picture accessible, maybe I can cut it and splice something new in?

OR, am I better to buy OEM bent and coated lines and replace the whole thing up to the engine bay. This would be difficult because the whole thing is routed above heat shielding, above exhaust, etc. I really don't want to have to mess with the exhaust...

Any thoughts, I'd appreciate greatly! Again, I imagine that a seized flare nut is a very Civic-relevant question, so I hope it's ok that I'm asking here.

Thanks!

 
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A difficult question

 
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Very helpful 👍 /end sarcasm

OP your best bet would be to splice in a new section of brake line, you should be able to strip that plastic off like wire insulation. You can buy line, fittings and a flare tool for under $100.
If you're not comfortable with making brake lines a shop would probably charge like $150 a side to fix.

 
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Thanks! I ended up doing just that. I had to cut back the line after the second bend to have enough room for the flaring tool and flare nut, and I had to sand off all of the rubberized coating just to get the nut on. Managed to get a good flare on the OE line on the second attempt, and spliced in a section of flared NiCopp line with a brass union. Tried tightening to about 10 ft. lb with a crowsfoot, but it felt like too much, so I just snugged it down tight with the flare nut wrench (this is the only part I'm not sure about). Did some tests with the car up to simulate panic stops and sustained pressure on the pedal and haven't seen any signs of leaks. Next step is a road test. I'll probably spray some rust-proofing on the steel lines where I sanded off the rubberized coating. I'll put it up again in a day or two to check once more for leaks, but I think it's likely fixed! Thanks for the advice!

 
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Good stuff 👍
I have never heard of anyone torquing a brake line, you should be fine

 
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Sure looks like a good repair. Nice work.