master cylinder; that was one of the first things replaced on my 320i. Just don't get one from Advance auto parts. Their hydro rebuilds suck. Make sure your shoes in the rear are properly adjusted also. Thanks for the info gents. I should have thought of my old Chevy with non-power brakes, my right leg got very strong pushing down on that pedal as it took all the pressure I had to stop it. Would the bad check valve leak brake fluid, or just allow air into the system? If there's brake fluid floating around somewhere I want to know where it would be so I can clean it up. Oh, and if anyone knows the proper procedure for bench-bleeding the master cyl. I could use some how-to. I'll let everyone know how it turns out, thanks again! -alan 83 320i 79 320i