Here are the most likely culprits and why you shouldn't attempt DIY fixes:
* Brake Caliper: The most probable cause is a seized or frozen right rear brake caliper. This means the caliper piston is stuck, preventing the brake pad from releasing. Trying to fix this yourself requires specialized tools and knowledge of brake systems; incorrect repair could lead to serious injury.
* Brake Line: A restricted or damaged brake line to the rear wheel could restrict fluid flow, leading to inconsistent braking. Again, this requires professional diagnosis and repair.
* Wheel Cylinder (drum brakes – less likely on a '97 Grand Am): If your Grand Am has rear drum brakes (though less likely on a Sport Edition), a seized wheel cylinder could be the issue. This is another job best left to professionals.
* Parking Brake: While less likely to cause an *instant* lockup upon pressing the brake pedal, a partially engaged parking brake could contribute. Make sure it's fully released.
* ABS Issues (less likely for instant lockup): Although less likely to cause an *instant* lock-up, a problem within the Anti-lock Braking System (ABS) could contribute. Diagnosis requires specialized equipment.
What to do:
1. Do not drive the car. This is crucial for safety.
2. Have it towed to a qualified mechanic or repair shop. Describe the problem clearly.
3. Do not attempt to fix it yourself unless you are a trained mechanic with the appropriate tools and safety equipment. Brake systems are complex and require expertise to avoid creating further problems or causing injury.
The cost of repair will depend on the specific problem, but ignoring it is far more expensive and dangerous in the long run. A seized caliper is a relatively common and relatively inexpensive repair, but other issues could be more costly. Get it checked out ASAP.
