Brake pedal noticeably stiffer; brakes kick in quicker -- what could it be?

Factual Questions
1

What does it mean when a car’s brakes “stiffen” and become more responsive on their own? No recent brake maintenance to speak of.

We’ve got a 1998 Ford Crown Victoria, which AFAIK has 4-wheel disc brakes and anti-lock braking (ABS on all 4 wheels, I’m assuming?). Until today, the brakes had a nice, medium feel – you wouldn’t get whiplash from brushing the brake pedal, but neither did you have to stand up on the brake pedal to slow the car. To me, the brakes seemed just right.

Today, the brakes seem noticeably stiffer. Less pressure is now needed to stop the car – indeed, using the same foot pressure as yesterday causes a mildly “bucking” stop. It’s possible to depress the brake pedal to the floor once stopped, if that matters – so it’s not like something is blocking the pedal.

I am checking the brake fluid level in a little while just to make sure nothing obvious is amiss. But what I’m wondering is what would cause the change from smooth, even braking to a decidedly sharper, stiffer braking. It’s not been hard to adjust to the stiffness, and the car stops just fine. It’s still possible to brake gradually, back out of a parking spot with a foot on the brake, etc. – it just takes less foot pressure than it did yesterday.

The one thing that’s occured to me so far is that maybe the anti-lock braking system (ABS) is shot or somehow compromised. Only thing about that is I’d have expected the Brake console light to come on if the ABS was having problems … and that light has not come on.

So, in sum, what could cause such a hopefully inoccuous symptom? Can old brake fluid thicken over time or something? Can’t think of much which could logically cause stiffening brakes.

Thanks in advance for any advice.

2

New brakes?

::d&r::

3

It’s an unusual symptom. My first thought is something gone wrong with the booster (vacuum operated device which makes for power brakes – it amplifies the pedal pressure to operate the master cylinder).

4

I had a similar problem once that turned out to be caused by a pebble that had gotten under the brake pedal and fallen into the tube that contains the rod that connects the brake pedal to the brakes. (I’m obviously not a mechanic.)

5

have you had reason to brake hard recently? some brakes will self adjust when you hit them hard…I cant really give exact details cause I dont know them but that might be your culprit.

6

Leakage from the axle bearings, especially in the rear, can cause brake grab.

7

Have the master cylinder checked out.

8

Perhaps the cable of your emegency brake is binding (not fully releasing). Does it feel ‘looser’ to apply the e-brake then it did?

9

Thanks for all the advice, everyone. My problem was similar to laina’s, except it was a chunk of floormat instead of a pebble. Brakes are back to normal now.