The power brake pedal pushes back against my foot when I apply the brakes.
Mercury Sable, 1993, front wheel drive, six-cylinder engine.
There is no issue of safety; the car is completely controllable during these events. It’s just that the pedal, while being pressed, pushes back against my foot. Feels like a live animal is in there. Slight pulsation while this is going on, never for more than a few seconds, and the car is completely under control all the time.
The initial force of my foot on the pedal does not seem to be any greater than at any other time, so it seems to me that the power brake system is operating properly right from the start.
Doesn’t lose braking, doesn’t jerk to a sudden stop. No strange noises.
Started over a year ago, happens only when
cold, only on first application of the brakes (of the day), never again (until the next day or a following day) but is so intermittent that my mechanic cannot analyze it. He advised me to wait until it happens every time, all the time. The car is not cooperating. I sometimes go a week before it occurs again.
Any suggestions?
[b]“happens only when cold, only on first application of the brakes (of the day), never again (until the next day or a following day)”
“Slight pulsation while this is going on, never for more than a few seconds”[/b]
What you are experiencing is the ABS system’s “self-test”, which is supposed to occur when the car is first started. As to why you did not notice this prior to a year ago, I can’t say, but what you are currently experiencing is normal. For confirmation of this information (and also for a wealth of other vital information about your car) consult your Owner’s Manual.
Incidentally, since your mechanic is not aware of this information, I am not especially impressed with his expertise!
There is an brake pedal position sensor that the ABS uses. If it is out of adjustment, then exactly what you describe is the result. It is near the brake light switch. The factory service manual has a simple procedure for adjustment of this. I had this problem once, and this is what fixed it.