Hi Everyone,

My '89 740 16 V with ABS has developed a problem in which it doesn't stop very well when I apply the brakes. The master cylinder is new. I also bench bled it first and used ATE Dot 4 fluid. There's plenty of pedal pressure, but the car just doesn't stop like it should. There's also a noticable pulsation at lower speeds in the brake pedal. I'm thinking it could be a problem with the ABS pump. The rotors/ pads are good. Any ideas would be appreciated.

Thanks!
Dave

When the ABS pump turns on, you should notice it immediately: a loud buzz and rapid vibration. Is the vibration you are feeling related to wheel rpms? Does the pedal move toward the floor as you keep pressure on? Did this begin immediately after the m/c was installed?

More data points needed...

Hi,

This problem was occuring before I installed the new MC. Yesterday I went through the bleeding sequence and that seemed to help it. I was able to flush out the old fluid. Yes, the pulsation occurs at lower wheel rpms. It still seems like something is off with the brakes. I don't hear the sound from the ABS pump that you described.

Thanks,
Dave

ABS is not active during normal braking. Is the power assist working OK, got vacume to it?
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David Hunter

Hi David,

I haven't checked the power assist yet. Maybe I have a vacuum leak? What is the best way to check that?

Thanks,
Dave