I noticed ever (EVER!) so slightly that my car vibrates a little when braking from high speeds, but this ONLY happens in one type of situation, braking on a freeway downhill off-ramp. The steering wheel doesn't shake, but I can feel the vibration coming from the undercarriage area. My parents' Kia Sedona has this same problem (vibration coming from undercarriage area, steering wheel barely shaking), but magnified probably ten fold, and it happens during any kind of high speed braking and not just downhill.

Is this problem still caused by alignment? My car has 48600 miles.

 

can be allignment it also could be tires. it could be worn suspension components.

 

check your lug nut torque, way over torqued can cause issues.

 

The problem is likely brake chatter, and is typically the result of improper bedding of the brake pads. In my experience, it can also be caused by getting the breaks very hot and keeping them pressed down in one spot when stopped at a light. This results in an uneven deposit of pad material on the rotor.

You can read more about it here:

http://www.stoptech.com/tech_info/wp...rakedisk.shtml

 

Even though the steering wheel doesn't shake it could still possibly be your rotors.

 

If two different cars have it in the same spot I would suspect the road surface.

 

Can't be road surface, because the Sedona does it anytime during high speed braking. And if I tried braking on the same road with my dad's pickup, I wouldn't notice it.

For that brake chatter thing, would all I need to do to is change the brake pads and properly break them in, granted my rotors are still okay (since it's still very hard to feel the vibration)?

 

COuld be the brake rotors which such (IMHO). If its the rotors you'll really notice it when stopping above, say 80-90

My car does the same thing and I've been pretty gentle to the brakes....

 

If you just change the pads, you will still have the problem (assuming this is the problem). That's because the "chatter" is caused by an uneven deposit of pad material on the rotor.

The best way to get rid of the problem would be to get your rotors turned. You might be able to get rid of the problem by evenly roughing up the rotor surfaces with sandpaper.

 

It's not the alignment. Vibration under braking is 1 thing, the brakes. You've got either front or rear rotors that are "warped". if you can pull up on the e-brake and get the vibration it's from the rear. If no vibration it's in the front brakes. Resurfacing the rotors is the fix.