I installed a new set of rear Girling wheel cylinders for my '66 122s, as well as a new MC. I noticed while bleeding that it leaks fluid from the brakeline-wheel cylinder connection even though they are quite tight. I'm using all original brake lines and the cylinders are from Swedish Treasures.

Any suggestions to stop this irritating problem?

Success! I think...
I bought some pre-flared brake lines, 1 30 inch, 1 50 inch and bent them to the approximate configuration as the old ones, using zip-ties to temporarily attach them to the rear axle. I'm going to go to the parts store and see if they have any of the nice metal ties like the original.

Installed them, didn't run into too much trouble...power bled, then had a friend step on the peddle hard while I went around with a drop light checking the backing plates and connections. No drips after about 1 minute of hard pressure, so I think it's done.

All right, I've replaced the left rear wheel's brake line. On Friday I'll do the right. I hope this works.

I took a look at my old wheel cylinder - it's double flare, not bubble. Some of you said it was bubble, I wonder if they had different line types in different years.

I had to replace lines in my 67 and you have to make sure that you use the right flare. The lines use the 'bubble' flare as stated in a previous response. They require and extra step in the flaring process.

Good luck and keep us posted!

No, none of them are crossthreaded or messed up. I only extra-tightened the connection when I noticed it was leaking. I checked it and it held up for about an hour, but a day later it was all covered in brake fluid.

I tightened it again and waited a few hours more, and still it doesn't seal. I suspect the new wheel cylinders more than anything, the old ones fit fine. I only bought the new wheel cylinders because they were about the same cost as the rebuild kit.

Moloko;

While the fitting might be "quite tight" it is obviously not quite sealed...there is very little rocket science here, and if you installed the replacement wheel cylinders then you are in a unique position to check out cause of the leak...crossthreaded?...bunged up line or flare/flareseat?...only YOU can tell!

Good Hunting!

While I'm no expert, it sounds like you may have cracked or deformed one of the flares on the brake line where it meets the cylinder. If that turns out to be the problem, making new brake lines is not that hard or costly to do, and you can reuse all your old fittings. It seemed a bit intimidating to me at first, but once I got a hang of using the flaring tool and making the cuts in the tubing square and burr free, it was fairly straightforward.

Tyler

If it isn't the wheel cylinders, then it is probably the flares, like you said. Do you know what kind of flares the brake lines have? I've heard bubble, but I'm not able to take mine off and look right now.

Usually just tight is adequate, more and you chance distorting the very close tolerances on relatively soft components. Fist time I changed my 122 MC a hard-to-trace slow leak drove me nuts, until backing off very slightly on the main line out of the MC sealed it up.

Not that that's necessarily your problem. Unfortunately you may have to do it all again to check.
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1966 122s, 1970 142s, 1974 142e... Blue is beautiful