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  #1  
Old 06-06-2014, 09:38 PM
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Anyone have a foolproof method for disconnecting corroded brake flex line connections

You know how we have that ~10" section of flexible brake line to the caliper. Usually you can get the caliper end off by the usual persuasion methods after penetrating oil and possibly heat cycling. What about the other end, which usually is connected to the hard brake line at a somewhat flimsy bracket. You wind up ruining the connection to the hard line, then you probably have to replace that line, etc. And you can wind up destroying the small bracket.

Anyone have any good tricks? I can see some cracks in my flex lines and I'd like to replace them, just some plain hoses, not braided SS or anything fancy. But I don't want to get into having to replace hard lines!

Rgds,
Chris W.
'95 E300D, 420K

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  #2  
Old 06-06-2014, 10:01 PM
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Grab the crimped steel part of the rubber line with vise grips, this will take the small bracket out of the picture.
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  #3  
Old 06-06-2014, 10:32 PM
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Then lock on to the hard line nut with a set of these:

The Original
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  #4  
Old 06-07-2014, 08:26 AM
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What sometimes works for me is "tapping the wrench". Instead of rounding the nut by simply bearing down, soak it for several days in penetrating oil. Then sort of tap the wrench...a little quick pressure, release, pressure, release, etc. The wrench should "click" each time. The same way an air wrench works to loosen a nut. In the worst case, you may need a new hard line.

Vise grips make decent welding clamps. Other than that, I've never found a use for them.
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  #5  
Old 06-07-2014, 08:50 AM
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if the hose is scrap anyway, cut it off close to the fitting. that expands the menu of tools you can use to remove it if its really stubborn
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  #6  
Old 06-07-2014, 09:56 AM
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A good pair of flare wrenches and some kroil do wonders
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  #7  
Old 06-07-2014, 10:45 AM
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Quote:
Originally Posted by Mxfrank View Post

Vise grips make decent welding clamps. Other than that, I've never found a use for them.
The vise grip that tango linked looks to me like it is perfect for this job. To apply even force or even tap, a wrench that is locked to the hex head seems to me worth trying. Any wrench that is able to slip on has some clearance and will make the already rounded flats worse.

I have been trying to release one side on my car - have tried flare wrenches, crowsfoot, flat, lots of pb blaster, heat and nothing has worked. A small pipe wrench may get flare off, but it will also ruin it. Monday I will try the special vice grip.

Btw, the other side came off with the crowsfoot and an extension bar.
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Last edited by Graham; 06-07-2014 at 11:54 AM.
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  #8  
Old 06-07-2014, 10:47 AM
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Geographical location is a large determinate to what you are dealing with. If the situation is bad. Heat really is you friend as the hoses are being scrapped anyways.

I dislike the expression of walk in the park but it does apply with heat in our extreme canadian east coat rustbelt corrosive area.

Part of the underlying reason is it will also break free the nut that bonds with the corrosion hard brake line as well. Beats turning the nut and and twisting the line as well in the process.

We have a system of dealing with really stuck bleeder screws as well. You heat and quench the area around them three times. Usuallly they come right out easily then. It is hopeless to apply heavy pressure to those screws because they will break off flush on many versions of them. Penatrating oil helps with a certain amount of corrosion but you have to let it sit and work. Plus it best be a good type. My problem with recommending heat is not everyone has ox/acet. Although there are hotter burning gasses available for simple torch heads. Even propane will help but it probably may not be enough heat.
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Old 06-09-2014, 02:35 PM
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My vicegrip 4LW came in today. It's a dinky little tool, just 4" long. I used a large pair of vice grips on the cut off flex line swage.

At first, the nut still would not budge. So I did all the other things. Turned both ways a few times. Applied heat using mini butane torch. Then gave it another go (with no extensions).

Even going through those steps, I had the flare nut off in a few minutes!

You do need to get the grips on real tight.

Nut is a bit rounded from previous (unsuccessful) efforts, but I think I can file it back to shape. Then use flare wrench to tighten into new flex lines and vice grip for final tightening.

I know I went all over the map thinking (and posting) about what I would do if this didn't work. But at least it was a learning process. I had never heard of those Cunifer lines (BTW, Napa Canada had coils in stock, but it was about $40). Hope I never have to use them though
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  #10  
Old 06-09-2014, 09:30 PM
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Rear hard lines

I had a problem bleeding one rear and may have to replace the flex lines. I sprayed the connectors with PBlaster and noticed the two connections were different. Both will no doubt be tough to disconnect.

Anyone have any thoughts about the non-standard connection? No spring clip, but it is very solid.

Rear Passenger side flex hose connection (modified?)




Rear Driver side connection (appears original design)

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  #11  
Old 06-09-2014, 10:52 PM
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they both appear to be original design, but the top one is missing it's clip...
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  #12  
Old 06-09-2014, 11:31 PM
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Originally Posted by vstech View Post
they both appear to be original design, but the top one is missing it's clip...
Could be, but it is very solid. Whatever is holding it firmly in place is not apparent.

Don't see any welds. It is a tight fit in bracket. I thought originals had some clearance.
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  #13  
Old 06-10-2014, 11:05 AM
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the orange stuff (aka natural loctite) is holding it to the bracket. Such corrossion is best dealt with either kroil or acetone+atf mix.

The mix is really really good stuff, A little heat helps too (ensure you dont use heat with the mix is near)
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  #14  
Old 06-10-2014, 06:01 PM
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Quote:
Originally Posted by Zulfiqar View Post
the orange stuff (aka natural loctite) is holding it to the bracket. Such corrossion is best dealt with either kroil or acetone+atf mix.

The mix is really really good stuff, A little heat helps too (ensure you dont use heat with the mix is near)
You could be right. I broke it loose. Either the original clip fell off sometime or the shop that did the brakes last time put some JB-Weld or equivalent to hold the flex end in place.

The new flex hoses I bought from NAPA (for front) interestingly have 17mm hex on joint end vs 14mm for the originals.

Just waiting for new rear hoses. Hopefully the ViceGrip 4LW tool will help get the joints apart.

ADDED: Took short side out to separate joint: Bleed new front calipers.

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Last edited by Graham; 06-12-2014 at 10:11 AM.
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