[nathanso]

I'm most of the way through replacing all four rotors, pads, and brake hoses on my 380SL and I'm stuck on getting the RF and LF brake line flare nuts loose from the rubber brake hoses. I've tried;

o Liquid Wrench applied 10d, 3d, 1d, and 10m prior to attempting to remove the nuts. Fail.

o Aerokroil applied 3d, 1d, and 10m prior to attempting to remove the nuts. Fail.

o Flare nut wrenches (7/16", 9/16" these fit tighter than my metrics). Fail.

o Thick, non-chamfered flare nut crows foot wrenches (also SAE). Fail.

o Vise-Grip 4LW wrench with Vise-Grip 7LW holding brake hose fitting. Promising, but fail.

o Heat gun the fittings to 200F, then ice; then 200F, then ice. Fail.


I've tried every approach I've been able to research except using a torch as I still have a path backwards at this point, i.e. I can continue to drive on the current brake hoses (despite the somewhat rounded flare nut on my RF). Flame, I fear, will change that and possibly lead me down the DIY brake line flaring path.. a place I'm trying to avoid. My ABS car's RF brake line is very short thanks to the ABS controller being located behind the right headlight, and I know I can buy that pre-terminated line from the dealer and bend it myself. The driver's side brake line is quite another matter, however, with the line running from the ABS controller down the fender, across the firewall, i.e. not easily replaced!

Does anyone have any other approaches I can try? If I resort to using a torch, can someone outline the specific technique? I've been using an IR beam thermometer to gauge how hot my heat gun was getting the fittings but that may not work with an open flame.

 

[the lurker]

nathanso,
You could try a nut splitter although I have never used one on a brake line before.
The brake lines themselves are not tolerant to torch heat, care must be taken if using a torch. Ideally an oxy with small welding tip to heat the nut hard & fast at 6 & 12 is needed. One of those hand held butane torches will take too long to heat the connection over a too broader area and the heat soak could cause distorion to the brake line flare. Of course bleed the line first ! If you have never done this before or are not confident to tackle this I suggest taking the car to a specialist brake & clutch place, I'm sure they will have done it many times before, for the sake of a few bucks you can save yourself a lot of headaches,

the lurker

 

[nathanso]

nathanso,
You could try a nut splitter although I have never used one on a brake line before.
The brake lines themselves are not tolerant to torch heat, care must be taken if using a torch. Ideally an oxy with small welding tip to heat the nut hard & fast at 6 & 12 is needed. One of those hand held butane torches will take too long to heat the connection over a too broader area and the heat soak could cause distorion to the brake line flare. Of course bleed the line first ! If you have never done this before or are not confident to tackle this I suggest taking the car to a specialist brake & clutch place, I'm sure they will have done it many times before, for the sake of a few bucks you can save yourself a lot of headaches,

the lurker

I feel kind of sheepish taking these damaged flare nuts to a brake shop after farking them up.. but that may be my best option.

 

[SHAUNE55]

Another route you can take is if you buy or rent a small hand held flaring tool, you can just cut the pipe.
You can get double female joints, then you can put a new end on your pipe, flare it.
Then make yourself a new short pipe with the correct male ends to go from the flexi to the old pipe with the double female in between.
Sounds like a lot of messing but it's actually very simple and saves running that new long pipe...Good luck.

 

[nathanso]

I'm not intimidated by pipe cutting or DIY flaring.. I'm just reluctant to spend the cash on a quality flaring kit and don't know where to rent one. Anyone have a rental source or a flaring kit to lend/rent? BW member since 2002; 100% 300+ Ebay rating, so your property is safe with me.

 

[nobby]

It's hard to believe you are having so much trouble....I mean I believe it but... well you know what I mean.


You are changing the rubber lines so they can be sacrificed. You must preserve the hard line or more work...yes?

You know they are reverse thread, eh?






Kidding.


It sounds like you have tried everything......I have never needed heat to loosen brake lines but there is a first for everything.

Is it because of rust? Or are they just on tight?

 

[hugybyr]

I have had the same problem a few times and after trying with the two vice grips that didn't work I used the vice grip on the small fitting butted up against something solid and then used a chissel on the big nut. Use a chissel that is not to small or it will pop off. Go in straight in the center of the nut to make a good grove and then go in at an angle and give it a couple of good whacks and see if it it moves. No? then make the straight grove a little deeper if its bad and try again. I work on a lot of old rusty frozen stuff and it has worked many times when nothing else will. Good luck.

 

[nathanso]

No rust, nobby; this is a 100% CA car.

hugybyr, that's an interesting approach. I have a cold chisel set and will give it a whack (or two).

 

[nathanso]

Got the LF line loose using the Vise-Grip 4LW/7LW pair in a different configuration: Instead of setting them 15* apart and then squeezing the pairs together like pliers, I set them to be approx. 150* apart and then, while holding the 7LW against the shock absorber, I started stiff-arming the 4LW like a human pile driver. It freed up after two good pops.

Unfortunately, the RF flare nut was too far rounded for this technique to work so I'm going to have to replace that short section of line.

For any would-be brake hose shadetrees out there, the Vise-Grip 4LW/7LW pair worked far better for me than actual flare nut wrenches or even flare nut crows foot sockets.

 

[Fonzi]

I don't know the 380sl, but on my car, the brake hoses are the female end of the connection. So I would think the worse case would be cutting the outer brake hose nut off with a cutting wheel on a dremel. Sure, you won't be able to get it all without damaging the inner nut, but I would think you could at least weaken the outer nut to the point it would fall apart.

Too bad the nut on the hose line is ruined. At least it sounds like you got the one you really needed to get, and if needed you can replace the whole brake line if you choose that route.

 

[peteroc99]

I had an old VW sun bug pos but I could not get line off at master cylinder used a 24 inch pipe wrench it worked. Now I use very long extension bars to use the old leverage principle. If done early before you round off the nut it works. If in doubt I use my floor jack arm or an old shovel handle. Hasn't let me down, great on fuel line to filter at tank. Be bold and have at it it will break free.. If you try to be too conservative the bolt round out.... A fast jerk will do it... Every one complained fuel tank line is a real bear breaker turned it into a bunny, and no bolt loosener needed.....