[sgboulay]

I need some help/advice from those of us that opted to use Buick GN electric boost power brakes.
I've finished the installation and bled the system. The pedal feels high and hard as a rock with the key off(no voltage to the system). When I put voltage to the brake system, the pedal is semi firm and fades away under foot to the bottom of the throw, and the pump can be heard cycling on and off. Does anyone recognize this symptom? What's up with this? Have I bled the system incorrectly? I bled it with the no voltage applied. Is that wrong? Can someone shed some light on my problem, or point me toward someone or something who can?
Any help will be appreciated...... regards to all,
HHssss

 

[oldguy668]

You have to bleed the pressure circuit independently. If you bought a rebuilt unit, you should have received a big plastic syringe and instructions how to use it. You simply force fluid into the correct port on the MC and it pushes the air out of the pump circuit. Email me if you need a copy of the bleed instructions.

 

[cobramd]

Along with what Joe said it sounds like you still have some air in the braking system as well the pedal should soften but not have any fade at with the booster pressurized. As far as the booster system the check valve that keeps the boost pressurized may take weeks to start working properly. I was just getting ready to take mine out when the system finally started working the way it should.(the motor will not cycle even if the car sits for days at a time.)

 

[n559br]

Also make sure you have bled the MC front and rear. I had no front brakes until I used the syringe to pull fluid through the port for the front brakes. Even bench bleeding would not get fluid to start flowing. My power circuit worked great within a few times of cycling power after correctly forcing fluid into the pressure side of the master.

Ben