HOW CAN I TELL THE DIFFERENCE BETWEEN BAD CALIPERS OR BAD ABS
More detail, please. This is very vague.
When stoping, the car seem’s to viberate like the ABS has kicked in or the Roters are warped from heat or hard spots or what ever. This happens at all types of braking slow or agressive but seems to be not as bad if I press slowly.
Does the rate of vibration decrease with the speed of the car? That would be rotors. If the vibration is the same when frequency when driving slow or fast it would be the ABS. My money is one or more rotors.
Loose wheel bearings, worn suspension parts, even a bad tire can cause a brake shudder.
It always helps a bit if any info on the vehicle in question is provided; make, model, mileage, etc.
If you feel the brake pedal going up and down, you could have a groove worn into the rotor. Those grooves are often of uneven depth. This is the easiest thing to check.