corolla 01 air in the brake line

[shehzad1]

Corolla S 01 80,000 mile. For a couples months, I feel like, I have air in the brake line. I replaced the brake fluid. Put new brakes on front and rear. Replaced both the rear wheel cylinders.Bleed the system too many times, The problem is still the same. Please help me find my brake problem.
Today I tested master cylinder on my other corolla 97 and it work fine on that. Put the corolla 97 Master cylinder in Corolla 01, Still the same problem (Taking long to stop)??????????

[CJCride]

Sometimes a bad hose can be the problem. Have someone push the pedal while you examine each hose.

[rgurleyjr]

You could have a internal seal leaking in the master cylinder itself but I'm not quite sure how you can test it. Air in the brake system can be a pain to find and correct.