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-   -   Wk pulsing while braking (http://www.jeepgarage.org/f181/wk-pulsing-while-braking-63029.html)

dascenc 07-19-2013 10:58 AM

Wk pulsing while braking
 
Hello Everyone,

WK noob here. I recently purchased my first Wk, 09 3.7L V6 Brilliant Black with 69k miles almost a month ago. Ive only put just over 1k miles on it when it started pulsing during braking, it kinda feels like the brakes are gripping then letting go but ever so slightly and its only felt at slow speeds. Its not a vibrating feeling. I dont feel it in the pedal, its the whole vehicle (I can feel myself lurch forward just a bit) so I believe it might be warped rotor. Ill be ordering a clamping dial indicator to test the rotors for runout but I was looking for any other ideas of what it might be. Any input is greatly appreciated.

Thank You

SvenskaJeepGuy 07-19-2013 02:17 PM

Re: Wk pulsing while braking
 
warped rotor or air in the brake fluid would be my guesses

2005JGC 07-19-2013 02:44 PM

Re: Wk pulsing while braking
 
thickness variation in the rotor... the repair would be new rotors or have your current ones machined.

jeepgcoman 07-19-2013 04:40 PM

Re: Wk pulsing while braking
 
This is more than likely caused by "hot spots" on the rotors, and is really quite common. They can also happen for the reasons ID'ed above too, or excessive grooving/irregular wear patterns. Hot spots happen predominantly on the front rotors, as they take the brunt of the braking load and generate much more heat than the rears. If there are spots on both front rotors, the "pulsing" can come and go or it may even move the steering wheel back and forth (shimmy) when braking, depending if the rotor rotation is in sync or out of sync with each other. You'll also probably notice it more at higher speeds (may even get a good shutter/vibration) than lower speeds (mostly surging/pulsing). You should also be able to see these "hot spots" on the rotors, by looking between the spokes in the wheels. They will appear as bluish colored spots, some round, some elongated. They can be machined out, but usually return in short order, because the spots had been "hardened" previously and, unless you can completely machine them out, you'll be back where you started. I've got a small amount on mine, and I'll just drive it until it irritates me too much, or I wear the brakes out, whichever comes first. When you replace rotors, make sure you get good OEM quality (or better), and not the Chinese (low cost) ones. Some of those, new, are worse than what you take off. Been there, done that.

ChrisWk 07-19-2013 05:13 PM

Re: Wk pulsing while braking
 
I had this problem I hope I fixed it I just replaced my front rotors looks like hot spots I will take a picture of my rotors let you see this. I have not tested them to tired from replacing rotors , was a easy job with the right tools back soon

ChrisWk 07-19-2013 05:18 PM

2 Attachment(s)
Here picture of my rotors I changed today

Attachment 26737



Attachment 26738

jeepgcoman 07-19-2013 05:34 PM

Re: Wk pulsing while braking
 
Chris, can you get a closer pix of some of those hot spots? Looks like you have some long ones there. Also, what kind of rotors did you put on? Where were they made? What kind of pad did you use?

ChrisWk 07-19-2013 05:39 PM

Re: Wk pulsing while braking
 
Quote:

Originally Posted by jeepgcoman (Post 861310)
Chris, can you get a closer pix of some of those hot spots? Looks like you have some long ones there.

Will do heading to dinner, my brake pedal pulsed like crazy lite braking and hard braking.

dascenc 07-19-2013 10:04 PM

Re: Wk pulsing while braking
 
Thanks for the info everyone. Ill probably wait till it gets real annoying before I tackle it with a complete rotor swap.

dmsfun 07-20-2013 09:09 AM

Re: Wk pulsing while braking
 
Mine did that too before installing new rotors and pads. I went with Centric solid rotors from Tirerack, not costly and very high quality..Centric is a division of Stoptech.

ChrisWk 07-20-2013 09:15 AM

Re: Wk pulsing while braking
 
I installed Centric rotors and Wagner Thermo pads, my front pads factory had cracks in them the back did not look that bad. So your front rotors looked like my set? I got about 45k out of the rotors.

jeeper_57 07-20-2013 09:16 AM

Re: Wk pulsing while braking
 
rotor problem , i've seen it on WJ we machined the rotors and since then no problem


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