# Car stutters/jerks forward when pressing the brakes **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [January 31, 2019, 8:49pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702 "2019-01-31T20:49:25Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![bbroderick85](https://avatars.discourse-cdn.com/v4/letter/b/b782af/32.png) [@bbroderick85](https://community.cartalk.com/u/bbroderick85)\ **Post date:** [January 31, 2019, 8:49pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/1 "2019-01-31T20:49:25Z")
When I press the brakes to slow down, my car jerks or stutters forward. Not sure if it’s the brakes or something else. It’s kind of like when you ride a bike and keep pressing and releasing the brakes and it jerks you. Any ideas? ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [January 31, 2019, 8:50pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/2 "2019-01-31T20:50:20Z")
Warped brake rotors. Tester ---
**Author:** ![bbroderick85](https://avatars.discourse-cdn.com/v4/letter/b/b782af/32.png) [@bbroderick85](https://community.cartalk.com/u/bbroderick85)\ **Post date:** [January 31, 2019, 8:51pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/3 "2019-01-31T20:51:52Z")
That won’t show up on a diagnostic scanner will it? ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [January 31, 2019, 8:53pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/4 "2019-01-31T20:53:52Z")
No. Tester ---
**Author:** ![bbroderick85](https://avatars.discourse-cdn.com/v4/letter/b/b782af/32.png) [@bbroderick85](https://community.cartalk.com/u/bbroderick85)\ **Post date:** [January 31, 2019, 8:55pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/5 "2019-01-31T20:55:33Z")
Ok, last question, how do I know if it’s the front or back rotors? Thanks for your help ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [January 31, 2019, 8:57pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/6 "2019-01-31T20:57:22Z")
What kind of vehicle? Tester ---
**Author:** ![bbroderick85](https://avatars.discourse-cdn.com/v4/letter/b/b782af/32.png) [@bbroderick85](https://community.cartalk.com/u/bbroderick85)\ **Post date:** [January 31, 2019, 8:57pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/7 "2019-01-31T20:57:53Z")
2001 Porsche boxster s ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [January 31, 2019, 9:03pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/8 "2019-01-31T21:03:02Z")
Nine times out of ten the front rotors cause this problem. But to find out for sure, a dial indicator is used to check the run-out of the rotors. Tester ---
**Author:** ![bbroderick85](https://avatars.discourse-cdn.com/v4/letter/b/b782af/32.png) [@bbroderick85](https://community.cartalk.com/u/bbroderick85)\ **Post date:** [January 31, 2019, 9:04pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/9 "2019-01-31T21:04:12Z")
I’ll just buy new rotors and replace them, Thank you for all your help ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [January 31, 2019, 10:37pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/10 "2019-01-31T22:37:56Z")
Buy new brake pads, too. ---
**Author:** ![shanonia](https://avatars.discourse-cdn.com/v4/letter/s/9de053/32.png) [@shanonia](https://community.cartalk.com/u/shanonia)\ **Post date:** [January 31, 2019, 11:39pm UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/11 "2019-01-31T23:39:04Z")
> [@bbroderick85](#): > > how do I know if it’s the front or back rotors? If you have a parking brake that you can apply and release with one hand - like the between the seats lever with a release button on its end - that works only the rear brakes. You can apply/release it while driving and see if the rear brakes are working smoothly or not. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [February 1, 2019, 12:00am UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/12 "2019-02-01T00:00:10Z")
> [@shanonia](#): > > If you have a parking brake that you can apply and release with one hand - like the between the seats lever with a release button on its end - that works only the rear brakes. You can apply/release it while driving and see if the rear brakes are working smoothly or It is typical with modern cars that they have disc brakes all around, but that they have a tiny set of brake shoes (i.e. drum brakes) inside a hat-shaped mechanism attached to the rear rotor. If this Porsche has rear discs with a separate drum brake mechanism inside a “hat”, your suggestion will not produce any valuable results. Does the OP know whether his Porsche uses the disc brake mechanism for the parking brake function, or if it uses a separate set of brake shoes for the parking/e-brake function? ---
**Author:** ![shanonia](https://avatars.discourse-cdn.com/v4/letter/s/9de053/32.png) [@shanonia](https://community.cartalk.com/u/shanonia)\ **Post date:** [February 1, 2019, 12:10am UTC](https://community.cartalk.com/t/car-stutters-jerks-forward-when-pressing-the-brakes/133702/13 "2019-02-01T00:10:20Z")
Yeah, you’re right. I was thinking of the rear drum brakes on my Honda and even older cars.