i igeorge, The first thing that comes to mind is a possible booster failure on your car. If the pedal feels like you almost need to use both feet to make the car stop, that is a pretty good indication that either the booster has gone bad or the vacuum supply to the booster is not doing it's job. I am going to post some test procedures below for you to look at. If you determine that the booster is in fact the problem (probable) let me know and I can send you instructions for replacing it. At that time I will need to know which model Buick you have as well as the motor size. Thanks, Bob
The hydraulic and mechanical problems that apply to conventional brake systems also apply to power brakes and should be checked if the following tests do not reveal the problem.
Test for a system vacuum leak as described below:
Operate the engine at idle with the transaxle in Neutral without touching the brake pedal for at least one minute.
Turn off the engine and wait one minute.
Test for the presence of assist vacuum by depressing the brake pedal and releasing it several times. Light application will produce less and less pedal travel, if vacuum was present. If there is no vacuum air is leaking into the system.
Test for system operation as follows:
Pump the brake pedal (with engine off) until the supply vacuum is entirely gone.
Put a light, steady pressure on the pedal.
Start the engine and operate it at idle with the transaxle in Neutral. If the system is operating, the brake pedal should fall toward the floor if constant pressure is maintained on the pedal. Power brake systems may be tested for hydraulic leaks just as ordinary systems are tested, except that the engine should be idling with the transaxle in neutral throughout the test.
Auto Service Technician
40 year GM Tech. +30 Certified. ASE Master Tech.(expired, retired) Medium Duty, Heavy Line, Retired