Several things could be wrong with your vehicle if the pedal is vibrating when you apply the brakes. It could be alignment issues, problems with the disc brakes or brake pads, or suspension components could be worn out. It will probably take a diagnostic check to ensure which problem is creating havoc on your vehicle.
Check for Rusting
It is possible to have a rusty rotor issue and not need a replacement. Under the pad could be clean and the rest of the area could have a small layer of rust. As a result, there is an uneven surface that could cause a vibration when you apply the brakes. All that might be necessary is using a grinder with a pad to remove the rust. It should resolve the issue if the rotor looks okay and doesn't have any visible grooves.
Check the Brake Drums, Rotors, and Pads
The drums and rotors are part of the wheel assembly. When you apply pressure to the pedal, the vehicle slows down. With wear and tear, especially with excessive heat, they can become warped, which creates a vibration. If the parking brake is used when the brakes are hot, the drum can become warped. However, it is a common occurrence if the lug nuts are over-torqued when the wheel was changed. Also, with time, the pads can gather rust dirt or other debris which can cause a shaky stop.
Check the Hardware
If the caliper areas and brake pad braces have any corrosion or old lubricant on them, they will cause vibration and noise. Check these components and clean them if necessary
Check the Wheel Stud
Lug nuts hold the tire on the wheel of the car. Damaged threads on the wheel stud means the nut cannot hold the wheel as it should. This could result in an imbalanced distribution when you apply the brakes. Also, if the wheel stud is bent, it could cause other studs to sheer as well.
Check for Bad Alignment
The first sign of poor alignment with the car is the shaking when it is traveling down the road. Vibrations can be caused because the wheels are basically pulling against each other. You can test your vehicle when it reaches 50 to 60 mph (if there isn't any traffic). Try releasing the steering wheel briefly, if it pulls to the left or right; it needs an alignment.
It is always better to be safe than sorry. You depend on the brakes to work when you apply them. A vibrating brake pad could cause the car not to have the braking ability to keep you safe in an emergency situation. Contact a shop, like Belmont Husky Service, for more help.