Tips for removing stuck brake lines from the MC?

Bmachine

Bmachine

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My MC was pretty sad looking with lots of corrosion. So I ordered a new one and started removing the brake lines with an 11mm flared nut wrench. It worked great for 3 out of the 5 lines but two are really stuck. I am nervous about applying too much pressure and risk destroying the nut.

I've applied penetrating oil overnight bu that did not help. I will see if I can find a SnapOn truck and get a higher quality wrench bc the one I have feels a little loose around the nut.

Any other suggestions? Tapping with a hammer? Propane torch heat?

Thank you.
 
I would do heat before hammer, that could get ugly quick. Maybe a round of heat, more oil, then heat and give it a go.
 
You need good quality flare nut wrenches to avoid messing up the fitting. I use Vise Grips as a last resort. Really messes things up, but always seems to work.
 
According you to google u heat the flare red hot and melt the candle or beeswax at the connection

I usually end up with the vice grips very scientifically tightening them to just the right grip.

If you can squeeze an inch out of the line somehow it's easy to cut and reflare the line with a new nut.

Or...maybe go downstream the line to the next connection? It's easier to bend lines than one thinks.

Ymmv
A
 
its been a while since i have done this - but what i did was heat up the line, then put a flare nut wrench on it - then hit the top of the wrench with the palm of my hand in sharp blows.
 
I bought a propane torch from Home Depot for 15 bucks. You need not get things red hot. This thing has not yet failed me. Also flare nut wrenches are a must. You will use them once every 3 years but boy, they are a savior.
 
A thought

As I have learned from this forum most brake fluid will attract moisture and can cause corrosion and almost weld those flare nuts to the lines! One of the first things I would do is inspect the lines, if there is any corrosion on the outside they should probably be replaced- nothing worse than going through the motions and then finding the line is bad- Hmm, how do I know this?? :-) Anyway, the brake lines are long and do have some tough bends, and replacing them means the removal of many other things so you can make a successful joint/splice if necessary (it's safer than the multiple transitions between steel and rubber that already exist). So what I'm trying to say is that with a line stuck that bad on the master you may want to find a safe and easy spot to create a joint and proceed. Maybe you can find a spot that is hidden and requires minimal bends.
 
Not sure what you are using for penetrating oil but I would use PB Blaster...I have had really good luck with that stuff. After an overnight soak, I would do alternating cycles of nearly red hot heating and then cooling off by spraying more PB Blaster on the nuts...then do it again, and again, several times. Makes a bit of a toxic cloud so if you have a paint respirator or can do it outside that is highly recommended. Several cycles of heat and spray cool down should do the trick...with a good wrench. Also, I sometimes slightly tighten the nut as well, so that you can get some movement going in the threads. Don't try to turn the nut until it is really hot. Also, make sure you are soaking the area where the brake line passes through the nut as well so that you don't end up twisting the brake line and wrecking it...cause you could have just cut it and saved all the trouble.
 
Thank you very much all for the great replies. I got a torch from a neighbor tonight and after reapplying penetrating oil I will try the torch tomorrow.

I do not have PB blaster but I use Aero Kroil. Would PB blaster make mcu of a difference?

Once thing I noticed is that the two flare nut wrenches I tested both felt a little loose around the nuts. I would think they should be really snug. Anyone else noticed that?
 
Last edited:
Bmachine said:
Once thing I noticed is that the two flare nut wrenches I tested both felt a little loose around the nuts. I would think they should be really snug. Anyone else noticed that?
Click to expand...

Exactly, then they tend to round the nut corners a bit more, which makes it looser and you're in a vicious destructive cycle. If you have the room, clamp the jaws of the flare wrench totally closed with a long nose Vise Grip. If the nut is already slightly rounded I would try the long nose/flat jaws VG very tightly on the nut itself.

I really like ATF/acetone 50/50 (roughly) as a penetrating oil. Has worked very well for me and I never run out of it.
 
FWIW there are a number of forums that quote this informal test of force required to turn a nut:


Penetrating oil ..... Average load
None ..................... 516 pounds
WD-40 .................. 238 pounds
PB Blaster ............. 214 pounds
Liquid Wrench .... 127 pounds
Kano Kroil ............ 106 pounds
ATF-Acetone mix....53 pounds

The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone.


I've had good luck with Liquid Wrench as it appears to be quite effective and easy to get in spray form. I've been curious to try the acetone mix but have never gotten around to it.
 
i use a flare nut wrench

but when really stuck after all those attempts to loosen the nut one thing that Works is go and "do" the nut a bit, by doing this you just loose the threads a bit and BTW you are using the fresh side of the hexagonal faces once you have made the opposite faces a bit round and just about to lose the nut
 
One would think the ATF acetone mix would preclude using a torch. I do know that PB Blaster smokes like hell, stinks but does not catch fire.
 
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