1972 FLH. My front brake was always pretty soft from the day I bought the bike. While bleeding it, my dsd accidentally mixed DOT 3 with the DOT 5... So I had to clean everything and replace the rubber pieces. So I rebuilt the master cylinder, rebuilt the caliper, and replaced the oem brake line with a stainless steel line. And still, no matter how many times I try to bleed the system, nothing improves. Still very soft. I can pump it up and get a little pressure. But then it's gone again. I even tried the trick tying the lever back overnight. Nothing. Any suggestions?

 

we use a syringe filled with dot 5 from the bleeder to the master and have it level the master even if you have to tie it to the bars that way

than take a 7/16 wrench about 6 inches long and tap ( tap tap tap kind of thing ) the line starting from the caliper all the way to the master than LIGHTLY tap the master not to damage the chrome or paint

Tapping the line / master for some reason makes the small air bubbles move up ward and than poping the lever to make a bang helps it purge air completly

 

Try the above fix first. If that doesn't do it, try this:

take the caliper off the bike and put something inbetween the brake pads about the same thickness as the rotor. Rotate the caliper so that the brake line is pointing straight up.

Double check that all the fittings on your master cylinder and caliper are tight.

With the cover off the master, gently work the brake lever open and closed and look for bubbles. You may get nothing for awhile, then a whole bunch of little tiny ones. When you think it's clear of bubbles, let it sit overnight then try again in the morning, just to be sure.

Put the caliper back on; should take care of the problem.


carl