[1]Soft Brake Pedal
A soft brake pedal is a MAJOR brake issue. If your brake pedal feels squishy, "like stepping on a plum," and won't stop on the way down unless you pump it, or the brake pedal sinks to the floor with little or no resistance, you have a dangerous situation and should NOT drive any further! If you do, it could be a matter of minutes until you smash into something.

When the brake pedal gets soft or sinks to the floor, it's generally due to a leak in the braking system, most commonly the master cylinder leaking internally or externally and sometimes it likely from the rear wheel or from the front carlipers.

A master cylinder may fail in two ways: internally or externally. If the brake fluid reservoir is full and there are no signs of leaks, the problem is usually an internal problem that you can’t identify just by looking at the master cylinder. Don't drive the car in any case; there is something wrong with your brakes if the pedal is soft.

[2]Car Pulls to One Side When Braking
A car that pulls to one side can be annoying and also dangerous. This braking problem can be caused by several different things, even the tires (see below), but the most common cause is a frozen caliper. Over time, a caliper can freeze up gradually, a process that can go unnoticed for a long period of time.

One way a caliper can freeze up is by the piston on the caliper being stuck in its bore. If the dust boot that protects the piston from the elements gets torn, water and debris will penetrate the metal in the caliper and cause rust and corrosion. If the piston is stuck, and the fluid pressure can't push it back into the bore easily, the pressure on the pads will be uneven and the car will pull. To fix this problem you will need to replace the caliper.

Another possibility is that the pistons got bent, during a brake job or a car accident, and can't move freely anymore, causing the caliper to bind and limiting the amount of pressure to the pads.

The caliper can also freeze up if the caliper slide pins have lost lubrication because they have not been maintained properly. If the slide pins are your problem, they need to be cleaned and lubricated or replaced

[3]Steering Wheel Shakes When Brakes Are Applied
This is a very common brake issue on all makes and models: when you’re driving at highway speeds and you apply your brakes, the steering wheel shakes.

There are many possible causes of this shaking, including the front rotors being warped, hot spots (slight irregularities) on your rotors caused by excessive heat, or pad impressions. If your car sits for long periods without moving, moisture from rain or high humidity causes your rotors to rust, except for the patch of rotor surface where the pads rest. This patch of uneven rotor surface is called a pad impression and will cause the brakes to pulsate.

[4] Brake Pedal Pulses Up and Down When Applying Brakes
If every time you apply your brakes, your brake pedal pulses up and down, the problem is usually caused by the rotors being warped or out of true. As rotors age, they go through the heating and cooling process thousands of times, so it's inevitable for them to lose their shape or trueness. If you do a lot of highway driving and you happen to be hard on your brakes, you will probably run into this problem many times in the life of your car.

[5] Whole Car Shakes When Brakes Are Applied
If your whole car shakes when your brakes are applied, it could be just your rear brakes. As a rule of thumb, shaking caused by a problem in the front end of the car will be felt in the steering wheel, while shaking in the rear will seem to affect the whole car.
To determine if your rear brakes are the problem, you need to test them in isolation.