mic_crispy

when i brake kinda hard over a bump or something i hear like a spring? sound and i can feel it in my pedal and i kinda loose braking until i take my foot off the brake and put it back on... any idea? i did a brake pad change not too long ago... did i not bolt something down? thanks

mic_crispy

its like a boingggg with a tapping sound that i can feel in my brake pedal..

xviper

It's your ABS working.

mic_crispy

really??? its VERY audible throughout the cabin... i had abs in my last car and BEARLY felt it.. but never heard it at all.. people sitting in my pass seat can hear it.

xviper

I get this sort of noise and feel whenever I apply the brakes moderately to hard going over uneven road surfaces (corrugated, washboard roads) or hitting the brakes at the right moment when going over a speed bump. Understand that when you go off the trailing side of a bump, you reduce the weight of the tires on the road and with the same brake force you started with before you hit the speed bump, the reduced weight can lock up the front brakes easily. The ABS will kick in to unlock them since your rear wheels are still turning under the same grip (hasn't hit the speed bump yet).
Corrugated roads are particular good for making the ABS go nuts (even if the road is perfectly clean and dry). Test this for yourself. Go find such a road and approach it relatively slowly (maybe around 15 mph), then hit the brakes lightly to moderately. You should get a similar reaction. At least in this way, you can compare it to what inspired you to post this thread. Not only are you getting the ABS cycling but you are also getting an aggravated suspension bounce due to the road imperfection and ABS.

mic_crispy

ah okay... makes sense... my first thought was the abs but i figured it was way too loud for it to be this.. but i guess i learn something new everyday! thanks for the info... much appreciated..

RACER

ding, ding, ding, ding, ding, ding, ding, ding.....we have a winner.



Whats up Dave

RACER

I don't think the front and rear wheel speed sensors work in unison with one another. If all four tires broke adhesion simultaniously, ABS would not kick in. Correct me if I'm wrong, I think the wheel speed sensors work in unison with the pinion shaft inside the transmission, where the speedo is connected to.



Approaching a stop sign at 30 mph on cold, worn out tires even with minimal pedal pressure will engage ABS big time. (dry road)

Wisconsin S2k

there is an independent speed sensor on each wheel. just because all 4 tires might lock up simultaneously doesn't mean they won't work. If you're driving along at 30mph and suddenly you hit the brakes, and all 4 speed sensors go from 30 to 0, the ABS kicks in because of the sudden drop.

xviper

Hey T. Haven't seen ya here in a while. Don't be such a stranger.