Buick Regal Brake System Trouble:Poor Brake Effect & Brake Light On

A owner of Buick Regal (equipped LB8 V6.2 2.5 L with 136 thousads miles made 2005) driven this car to my garage,and conversated to our technicians his car trouble:poor brak effect and brake light on the dash.This article talk about how to solve Buick Regal Brake System Trouble By the real case.


Our technicians tested on the car and found below trouble symptoms:

1. Try several times to pressed and released the brake pedal,but the brake light was still on.

2. The brake effect was poor when pressing the brake pedal.


Buick Regal Brake System Analysis:

The rear and front wheels of Buick Regal equipped with disc brakes system,and rear wheels work as parking brake.The brake sytem consist of brake pedal,vacuum booster,brake master pump,brake hydraulic pipes,brake sub-pump and ABS,show as below diagram:

Buick Regal Brake System Trouble 1

Trouble Analysis:

Firstly,our technicians checked the brake fluid of brake tank and found the fluid level was under the scale line.Asked the owner for car maintance status recently,the owner described that replced the 3 filters and brake fluid several days ago.Considering some bad irresponsible repair workshop in order to save their cost,and lacking brake fluid and flow the air into the brake sub pump.So technicians bleeded air for 4 sub pump(ABS Bleeding) and added brake fluid up to scale line.


Secondly,technicians tested the Buick Regal again and found the brake effect had restored.Then we need to test brake effect at a high speed,driven the car up to 45 mile/h and pressed the brake pedal,found that in the process of braking, the right direction deviation.


It is most likely that:

1. Right rod joint or bushing have worn and loosen result in the right direction deviation.

2. Lacking brake force of right sub pump result in brake deviation.


Lifted the car and checked the revelant parts mentioned above:

1. Suspension components (work normally)

2. Brake system pipes (work normal,no worn and damaged)

3. Brake master pump (keep press brake pedal and there was no leak,work correctly)

4. Checked the bleed bolts of each sub pumps,and technicians found there was leak on the bleed bolt of the right front sub pump.Disassemble the right front bleed bolt and found the hole have been worn as below.

Buick Regal Brake System Trouble 2


Replace the right front brake calipers, troubleshooting.


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