troubles removing front brake lines
 

I'm replacing my flexible brake lines. I've removed them from the calipers but am having trouble removing them from the hard lines. I've soaked them several times in PB Blaster and have an 11mm flare wrench, but even with that the hard line nut is starting to round off.

What's the best approach to breaking this free? Should I use the 11mm flare wrench to hold the top nut in place while turning the 17mm soft line, or vice-versa?

Any other tips on getting this done without ruining anything? Thanks.

I do not have experience, and it sounds like you are on the right track
with PB blaster. Somebody here is going to have a better answer.

But is heat possible on the outer nut ? Without burning the rubber ?

Heat would expand the outer nut and help the PB get in.
You asked about which to turn and yes I would probably try to keep the 11mm
hard line steady and work at getting the rubber line free.

My thinking here is that the rubber line is being sacrificed and going to be replaced so if damaged does not matter.

In my experience you need to do the best you can. The chances are that you'll have to replace the hard line(s) as well as the flexible ones... to be honest I finding arsing about with things like this extremely irritating so you'll see me reaching for the mole grips faster than most!

When you fit the new ones put a smidge of vaseline / grease over the joint when fitted in place to try and stop it from corroding.

Get a Vise Grips 4LW Locking Wrench. This particular Vise Grips tool will hold the hex-head fitting on the hard line securely WITHOUT damaging it. The LW series is unlike any other Vise Grips product. I have all three, but the only one I ever use is the little one.

Using the 4LW, clamp it down on the hard line fitting so you can hold it fast. Cut the hose at the connection to the hard line so you can get a deep 6-point 10mm socket on the hose fitting.

Hold the locked-on 4LW steady while turning counterclockwise on the socket wrench (I like to use a long-handled 3/8-drive ratchet). You do NOT want to apply rotational torque to the hard line fitting. Hold it fast or you run the risk of kinking the tubing.

I have removed 40-year-old brake hoses using this method. Haven't lost a hard line yet.

That's an excellent tool. I'm definitely getting one for this specific purpose. There is always a danger of rounding the nut when using the flare wrench or the standard vice-grip............even when heat is applied.

I bought a set of Craftsman flare wrenches years ago and to my chagrin found that the set lacked an 11mm wrench, which is what most German cars need for brake line fittings. Then there's the issue of corrosion, which can eat away at the flats on the fitting and make the wrench a loose fit.

Sometimes you've really got to crank on that hose fitting to make it let go... the job is a challenging combination of force and delicate care. The right tool can make all the difference. :D

Classic Sears strategy: sell a "set" that is not really complete, then you have to buy the missing pieces at much higher "individual" prices.

Man what a tool!

Just think how many brake lines I could have saved...

I've ordered the vise grips. If that fails, what is involved in replacing the hard lines? Can they be bought pre-bent?

thanks for all the advice.

Heat the fitting with a propane torch for about 30 seconds.

Use the vice-grips.

They will not fail.

Some ideas:

If you're replacing the soft lines anyway, just cut them so you can use a 6-point socket on that side.

PB Blaster is decent, but there are better 'industrial-grade' lubes out there. If you can track down AeroKroil, that will help. You can also try a 50:50 mixture of ATF and acetone.

As others have said, a torch will also help.

The chain autoparts retailers carry generic steel brake lines for "European" cars. It's the same size as the MB OEM. I bought mine from Advance Auto Parts for under $10. Just be careful and patient when bending them yourself, so you avoid kinking the lines.

Cunifer Copper Alloy Brake Tubeing
 

This is some pretty good tubeing, bends w/o kinking and will not rust.

Federal Hill Trading Company

may be pricy for some of you, and the tool they show in the video is a good chunk of money, but sure is a slick way to flair the ends,

Charlie

Vice Grips 7LW FTW! What a great tool, thanks for the suggestion. The passenger side bolt was pretty well rounded and it still worked.

I also cut the flexible line and used a half inch drive six point deep socket with a breaker bar on the flexible line fittings.

On the passenger side the metal bracket that surrounds the top of the flexible line was slightly bent and was preventing me from getting a good grip on the entire hard line nut. I ended up snipping that piece off with some tin snips to make more room.

Other than holding down the plastic bracket for the break-wear wires, is this piece necessary to replace?