This is not much information, but I'll give it a try. If the front brake rotors have too much run-out, "wider in some spots than others" then the rotors need refaced or replaced. If the problem is in the rear brakes, the brake drums are out-of-round and need resurfaced. If you feel the tremble in the brake pedal when you brake, then the problem is certainly in the brake system.
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He is correct...the rotors are probably warped. Replace the rotors if they are warped that bad. You can get them turned but they are going to be thinner than new rotors and whatever caused them to warp last time will happen faster. (heavy braking and riding your foot on the brake can cause the rotors to warp)
The braking system makes a car stop.
A car may tremble when pressing the brake due to several factors, primarily related to the braking system. Common causes include warped brake rotors, which can create uneven contact with the brake pads, or worn brake pads that may not grip evenly. Additionally, issues with the suspension or alignment can contribute to vibrations during braking. It's important to have the braking system and related components inspected to ensure safe operation.
change brakes or check drums
Fear Being Cold Earthquake Storms Death Spiders/Bugs Car Accident
Drum & Disc are the two types of braking systems on a car.
Braking
braking
Assuming you mean "braking", aggressive braking.
Hydraulics.
ABS??
The M3 BMW is a good car because of the features it has. It can be sold in 3 different models, and has upgrades. The M3 BMW has better handling, braking and suspension systems. The upgrades also makes the engine powerful and responsive.
If it is when you brake then there could be some loose hardware, if so tighten all the bolts that you can and if not when braking then it may be a ball joint.