Topic: Brake won't stay bled

[gregimotis]

So, my rear brake stiffens up nicely after a bleeding - for about four miles and then it's completely gone.  When I go to re-bleed, sure enough it's full of gas again.

Things I've tried:

replace bleed nipple.
flush system by bleeding through several ounces of brake fluid
bleed (lots)


I guess it's leaking somewhere (hose?), but wanted to ask in case there is something else I don't know.

[clarkjh]

Could it be sucking back past the brake piston and seal?  Old fluid, (as in long on the self)?

Just thinking with the fingers.

James