Breaking Brake Line Fittings

[Harry]

In a previous post, I noted that I was having to replace the brake shoes on my 230SL.  In the process, it became clear that I should also take that opportunity to replace the Slave cylinders on each wheel.  That went well on the driver's side and poorly on the passenger side, where the fitting could not be rotated separately from the line and the line failed.  When I moved back to the junction with the rubber hose, that fitting was like it was welded and I cannot break the now boogered up fitting free from the rubber line.  I expect that I may have to now proceed to the joint at the other end of the rubber line.

I am looking for the "home remedies" that have been used to successfully free these fittings?  What are some methodologies that have been employed?

Thanks,
Harry

[mrfatboy]

When this happened to me I heated the fitting with a torch and it immediately freed itself.

I protected everything around it with “heat shields” the best I could. I’m not a big fan of having an open flame  around the car but I took as many precautions as I could. It only took about 10 seconds of heat in my case.

Be very careful if you take this approach.

[Harry]

I tried that using a heat gun but I was worried on that particular fitting whether I would damage the rubber flex hose on the other side.  I'm going to have to sacrifice that and add the heat I need - more than a heat gun probably.  Thanks.

[Benz Dr.]

A few words of caution:

If the hard brake line won't undo from a brake hose your best bet is to use heat. Heating the fitting near the brake hose will make it pop off with shotgun force so your best bet is to cut the brake hose before you start and then clamp the hose with vise grips to stop any fluid leaking out. Brake fluid will burn and can easily burn you too. 

[ejboyd5]

Cut the hose close to the fitting allowing you to slip a socket over the fitting for a better grip.

[Harry]

Thanks all - good advice.

[ja17]

"Vice Grip" makes a special tool with short, strong jaws that have a hex opening in the jaws instead of the normal toothed jaws. It has worked 100 % of the time for me on damaged brake line fittings. It is available from most hardware stores. I'll post pictures if I get a chance later.

[ja17]

Here is a picture of the "Vice Grip" tool I use to break loose stuck brake line fittings.  It will work even on a damaged bolt or fitting. The jaws are shaped to grab on three sides and it will not damage the fitting or bolt any further than it already is. I use a standard 14mm line wrench along with the Vice Grip tool to hold the rubber brake hose.

[Harry]

Thanks Joe.

I cut the hose to get it clear of the fitting, then heated the joint with a propane torch, let it cool, heated it again and it finally came free using a 14mm 6-sided socket and a small pipe wrench on the 11mm fitting.  Brakes have to be the simplest thing in concept but they are a super pain in the elbow to actually work with.

BTW - this lines are double flared - right?

Harry

[ja17]

The lines are a metric "bubble flare" I believe. A double flare has a concave double layer end whereas the bubble flare end remains convex.

[Harry]

Thanks again Joe!

[Shvegel]

20 years ago I needed to replace some lines on my car.  Being a line mechanic in a foreign car dealership and very fussy about lines being just so I figured I would just Buy the tool and custom make the lines.  I figured I would get use out of it anyway.  I was wrong.  I never used it again.  Not once.  Well, 20 years later I dusted the box off and replaced all the lines on my car as part of my restoration so now I am down to $50 per use.  They do look sweet though.