# Pulsation when stopping **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** mercury\ **Created:** [October 25, 2010, 11:48pm UTC](https://community.cartalk.com/t/pulsation-when-stopping/56838 "2010-10-25T23:48:23Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![bsaucer](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bsaucer](https://community.cartalk.com/u/bsaucer)\ **Post date:** [October 25, 2010, 11:48pm UTC](https://community.cartalk.com/t/pulsation-when-stopping/56838/1 "2010-10-25T23:48:23Z")
Sometimes, when I slow down to a stop, I notice the car has a slight forward/backward jerking, as if the brakes are pulsating. I don’t hear a sound or feel anything in the pedal. Would it mosty likely be a warped rotor, and if so, which one? Or could it be an ABS problem? I have 2002 Grand Marquis ---
**Author:** ![waterboy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/waterboy/32/764_2.png) [@waterboy](https://community.cartalk.com/u/waterboy)\ **Post date:** [October 25, 2010, 11:50pm UTC](https://community.cartalk.com/t/pulsation-when-stopping/56838/2 "2010-10-25T23:50:44Z")
Warped rotors is the first thing to check. ---
**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\ **Post date:** [October 26, 2010, 1:14am UTC](https://community.cartalk.com/t/pulsation-when-stopping/56838/3 "2010-10-26T01:14:09Z")
As waterboy suggested, warped rotors is a good bet. Have you had the brakes replaced recently? If so did you replace the rotors, or did you try to get away without re-cutting them or replacing them? ---
**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\ **Post date:** [October 26, 2010, 1:25am UTC](https://community.cartalk.com/t/pulsation-when-stopping/56838/4 "2010-10-26T01:25:46Z")
Yes it sounds like a warped rotor. How could we possibly tell which one? ---
**Author:** ![lion9car](https://avatars.discourse-cdn.com/v4/letter/l/59ef9b/32.png) [@lion9car](https://community.cartalk.com/u/lion9car)\ **Post date:** [October 26, 2010, 1:50am UTC](https://community.cartalk.com/t/pulsation-when-stopping/56838/5 "2010-10-26T01:50:43Z")
It’s probably a warped rotor. If you feel it in the steering wheel, it’s probably a front rotor. If you feel it in the seat, it’s probably a rear rotor. ---
**Author:** ![bsaucer](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bsaucer](https://community.cartalk.com/u/bsaucer)\ **Post date:** [October 26, 2010, 1:32pm UTC](https://community.cartalk.com/t/pulsation-when-stopping/56838/6 "2010-10-26T13:32:09Z")
A couple of years ago, I had brake work done. The pads were OK, but I had the front rotors turned, and thewn one was replaced. The current pulsation problem has developed since then. I do not feel anything in the steering wheel or the pedal. Only the whole car is affected, but not every time I stop. ---
**Author:** ![tardis](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@tardis](https://community.cartalk.com/u/tardis)\ **Post date:** [October 26, 2010, 2:50pm UTC](https://community.cartalk.com/t/pulsation-when-stopping/56838/7 "2010-10-26T14:50:31Z")
Do not have the rotors turned. They are too thin to begin with. Replace them. The cost to replace vs. turn is almost the same anyway. ---
**Author:** ![waterboy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/waterboy/32/764_2.png) [@waterboy](https://community.cartalk.com/u/waterboy)\ **Post date:** [October 26, 2010, 11:08pm UTC](https://community.cartalk.com/t/pulsation-when-stopping/56838/8 "2010-10-26T23:08:06Z")
Make sure you have a place that does tire rotations tighten lug nuts properly. Improperly torqued lug nuts can cause rotor warp.