Brake line bubble trouble

[Nanonevol]

Trying to replace the hard brake lines to the rear brakes. Tracked down the right 10 x 1.25 fittings but confused on the flare making. I remember hearing somewhere I need to make a bubble flare. Bought a tool at O'reillys which I was told would make these but now that I have it I see it makes a folded over flare which I fear will not seal inside my new soft brake lines and other fittings. How to make a bubble flare? Do I have the wrong tool. I also bought copper lines on O'reillys recommendation (won't rust) but recall reading about problems with copper as well.

[DRUMMOND]

Its called a Double bubble fitting



this is how I made mine and the tool with a slight alteration







I then just snipped the soft washer of with snips and it fitted perfectly

[Nanonevol]

Wow! I never would have come up with that idea! Is that your own invention?

[Nanonevol]

The instructions on my tool show a two step process and it looks like you simply skipped the second step which folds the bubble in on itself. I'm not sure what the washers function is.

[So Cal Mark]

I wouldn't use copper, the brake lines should be steel. Remember, the O'reilly guy sells parts because he can't make a living repairing cars

[Nanonevol]

That's funny and I'm sure it's true. In fact a lot of auto parts guys I've seen don't know auto parts either. So why not for the copper? Is it too weak?
My problem of the moment is bleeding the system. All four calipers are rebuilt so I would expect a lot of air but the rears seem to bubble forever. My fear is that my "T" connection fittings on the rear axle are leaking air. Could this be the problem or should I just expect to have to bleed a lot of air?

[DRUMMOND]

When i did it without the washer it did not fit that well. I am not sure if you are using the same tool? without the washer the bubble was flatter than the original and I was not happy with the fit. With the washer it is exactly the same profile as the original in the photos and seals completely

[Nanonevol]

Yes, I have basically the same tool but couldn't quite get your results with or without the washer. I was a least able to make the fitting a bit convex but I think it's leaking at the "T" connection on the axle. I'm trying to bleed the rears but I think that leak is letting in air. Not sure what to try now. I may look for the adapters that Edelmans makes.

[So Cal Mark]

besides copper being too soft, it's made for compression fittings

[Nanonevol]

Crap! Damn those O'reillys guys!

[DRUMMOND]

From what I remember when doing the flares. I would get an uneven neck crimp from the basic tool, the washer helps keep it square when shaping the bubble at the neck, so when you tighten it up it applies equal pressure all-round in the caliper (no leaking)

[Nanonevol]

Thank you Drummond for all your help. I see what you mean about the washers. In fact I've viewed a lot of You-Tube videos on this and one persons tool had a side that was flat rather than concave so he could make the bubble flare without the washer.
Frankly I'm losing confidence in my ability to make a hard brake line joint that doesn't leak. I think I'll look around for a garage that can make the flares for me.

[klweimer]

I've never been cool enough to do reliable bubble flares either. What I've done instead is purchase small adapter fittings that you screw into all your brake components (calipers, master cylinder, etc) and they adapt everything to standard US brake lines. The fittings looks like so:
http://www.oreillyauto.com/site/c/detai ... &ppt=C0248
That way, you can screw up brake lines to your hearts content, and just keep going back to the parts store for more.
Kirk

[Nanonevol]

Ha! I think that may be the answer for me too.

[Nanonevol]

Another work-around might be to buy the line with bubble flare - but with the m10 x 1 fittings or whatever's available - and cut it, put on the correct m10 x 1.25 fittings and splice it back together.