Q: I'm feeling a shudder in the front of the car when I'm braking, more so near the bottom of a long hill. It seems to be getting worse. How serious a problem could this be? - Kelly
A. It sounds like your brakes, likely the fronts, are suffering from distorted brake rotors.
Brake rotors are like very thick dinner plates, typically constructed of cast iron.
Brake calipers clamp the disc pads, which are faced with friction material, against the rotor, converting kinetic energy into heat.
Brake rotors need to have a uniform and smooth surface in order to function smoothly and without noise.
Over time, especially with hard use, thickness variations and surface flaws can develop, causing symptoms like you mentioned.
Assuming adequate rotor thickness remains, they can be machined to a fresh/true surface. If surface cleanup will reduce thickness below the minimum standard, they'll need to be replaced (as a pair).
Perhaps at some or various times your brakes were worked hard, causing excessive heat, and rotor damage.
In a nutshell, you need to have a brake inspection performed, and likely new brake pads along with machined or replaced rotors. This is a fairly standard process.
Should new rotors be needed, ask for options, as cheap ones are not the way to go.
Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif.