So, I probably fucked up.

I got my '02 grand at 30k and I had a slight vibration when braking. By 70k it got annoying enough that I put new rotors on along with new pads and it went away until about 120k. This time, I only replaced the rotors and the vibration is still there. Should I have replaced the pads or could there be some other issue there this time around?

11/7/2010 12:42:12 PM

grand marquis aren't very well made. maybe that is the issue?

11/7/2010 4:22:52 PM

sorry, Grand Cherokee.

11/7/2010 4:52:39 PM

New rotors don't require pads, but it helps especially if they haven't worn perfectly flat.

Also, why did you replace the rotors at 120k? Were they worn to below minimum specifications? Usually your pads wear out faster than rotors. Though I'll admit I haven't done any work on domestics.

11/7/2010 5:00:33 PM

^

but in your case...new rotors require new calipers

<3

11/7/2010 6:23:20 PM

I have the same problem. 04 grand cherokee. initially replaced rotors/pads with advanced auto midgrade rotors/pads and they lasted maybe 6-8 months before the shuddering was back. next time went with slotted cryo rotors and higher quality hawk pads from tirerack.com. this lasted a little over a year before the shuddering is now once again almost unbearable. I am wondering if I should replace the calipers this time too, since the problem doesnt seem to be just the pads/rotors.

[Edited on November 7, 2010 at 6:31 PM. Reason : s]

11/7/2010 6:31:01 PM

50k miles before warping on new rotors for a midsize SUV isn't all that bad. Drive it fairly hard or have oversized tires on there?

11/7/2010 7:46:24 PM

why would you replace the rotors and not replace the pads.

that just sounds fucking stupid.

^ agreed

[Edited on November 7, 2010 at 7:52 PM. Reason : .]

11/7/2010 7:51:41 PM

are you torquing the lug nuts everytime a wheel is removed? jeeps are NOTORIOUS for doing this. I used to have this problem on my tj, and once I started using a torque wrench haven't had a warping problem at all.

I have wj (grand cherokee) brakes/knuckles on my tj so I have the same rotors/pads.

11/7/2010 11:22:38 PM

99-04 grand cherokees have issues with the brakes not being right. rotors warping, vibrations, and a pulsing pedal. there is tons of info about this on various jeep sites. i'd look there. and yes, you can replace pads/rotors individually.

[Edited on November 7, 2010 at 11:29 PM. Reason : dt]

11/7/2010 11:28:48 PM

JMSJ

11/8/2010 11:17:42 AM

Quote :

"Also, why did you replace the rotors at 120k? Were they worn to below minimum specifications? Usually your pads wear out faster than rotors. Though I'll admit I haven't done any work on domestics."

As pointed out here:

Quote :

"99-04 grand cherokees have issues with the brakes not being right. rotors warping, vibrations, and a pulsing pedal. there is tons of info about this on various jeep sites"

And mine is no different. The main TSB that was supposed to cover this problem required changing the calipers from Teeves to Akebono (might have that swapped) and the first time I encountered this issue I had hoped this is what it was but mine had apparently already been updated. I don't tow anything and I generally don't stomp on my brakes to stop, I'm kind of wondering if light pressure on the pedal to come to stops slowly is somehow worse for my Jeep than quick firm stops.

Quote :

"Drive it fairly hard or have oversized tires on there?"

Not at all. I pretty much baby it because I'm a cheap ass and want to make it last as long as possible.

Quote :

"why would you replace the rotors and not replace the pads. "

Because the pads had a ton of meat left on them, no grooves or anything noticeable that would have made me think to replace them.

Quote :

"are you torquing the lug nuts everytime a wheel is removed? jeeps are NOTORIOUS for doing this. I used to have this problem on my tj, and once I started using a torque wrench haven't had a warping problem at all."

Nope, and I assume I'm not putting the hammerlock on the nuts but not having commanded a torque wrench in a very long time I honestly have no concept of how much pressure is equal to how much torque.



Anyway, so at this point the vibration is there with the new rotors old pads. I suppose I should just put some new pads on there and see if that fixes it, but I can't imagine why it would?

11/8/2010 7:39:01 PM

Depends how much your rotors cost (no idea for jeep) and if you've got enough thickness left on there to turn them down flat again. Might be cheaper to buy another set outright, taking them to a good local shop already off the car would be roughly $10-20 per rotor. Don't forget if a set warps once, though, after turning them they'll warp again but faster under the same conditions. Tried looking at different manufacturers to see if any of them produce a fatter rotor?

Torquing would help rule out any overtightening issues. If you like to do your own work it's definitely a good investment to get a torque wrench. Stop by a pawn shop, usually they've got good deals on stolen tools.

11/8/2010 9:30:59 PM

you can pick up a torque wrench from harbor freight for under 20 bucks. That's what I've used for years. Did a side by side test with a craftsman wrench and they were the exact same. might not be the same quality, but producing the same torque value is good enough for me.

I have the teves calipers on my tj so that I can clear 15" wheels; I haven't had a problem with warping. I'm just a big believer in torquing lug nuts. i've had friends have their own wheel/tire combos pass them because they failed to properly torque them.

11/8/2010 9:37:32 PM