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When do you need rotors? (running bigger tires)

Old 09-25-2011, 01:18 PM
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Default When do you need rotors? (running bigger tires)

Hey guys, i have been having an on going issue with the Jeep. It is now officially out of it's warranty and when i slow down to a stop the Jeep itself pulses. The brake pedal is smooth, but the whole vehicle pulses forward when stopping. It's not too bad, but it is noticeable. I have nearly 72,000 miles on the Jeep with 63,000 or so running 35's. I think my rotors are warped, because sometimes when i hit the brakes the steering wheel shakes a little, and i have no steering wheel wobble at any speed otherwise.

So i bought rotors at advanced auto, front and rear because i've had both rear calipers lock up on me, and the pulsing feels like it's from the front, but occasionally the Jeep will not only pulse forward and backward, but i'll get some side pulse in there too like a rocking motion with the forward/backward pulse.

So i have new rotors front and rear, but i have not installed them yet. I figured i would doulble check and see what you guys have done and when you knew you needed rotors. After i mount these, the $116.85 isn't coming back. The brake pads themselves are good though.

Thanks
Old 09-25-2011, 01:23 PM
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If they have never been machined, then machine them. Depending on how bad the runout is, you should be able to cut them once or twice before replacement.
Old 09-25-2011, 02:54 PM
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New rotors cost as much as getting them turned on a lathe.

Definitely sounds like your rotors are out of spec or warped.

Make sure you put new pads on it while you are at it.
Old 09-25-2011, 03:13 PM
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The $30 China rotors from Autozone or Adanced are NOT the same as the ones that came new. The $30 ones will definately warp more easily than the factory ones.
Old 09-25-2011, 04:00 PM
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With 72,000 miles on the clock, I would not machine the old rotors. Definitely get new rotors, and I would also replace the pads at the same time.

Mabar
Old 09-25-2011, 06:00 PM
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Well since i already have them i might as well toss them on especially with the mileage i have and the issues they have gone through. I am alright as far as pads go, i recently replaced them. (always go with the lifetime pads, you never know when a caliper is going to lock up on you!)
Old 09-25-2011, 06:52 PM
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You can't actually "warp" rotors.

h tt p://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

If it were me, I'd first inspect the tires. If there's no "cupping" or uneven/funny looking wear, it's probably not them. You can go and have them balanced even if you choose, but if it's not all the time, it's likely not the tires. You could also try rotating them for the heck of it.

When was the last time you had any brake work done? (pads etc..) Sounds to me like it's time for a good brake job. If you haven't done the rotors or pads in the last 50k miles, I'd definately replace both and bleed the lines (replacing the fluid as well if it's pretty dark looking).

Edit: you can/should also check your brake lines as well.

Last edited by Steelgrave; 09-25-2011 at 06:56 PM.
Old 09-26-2011, 06:53 PM
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Originally Posted by Steelgrave
You can't actually "warp" rotors.

h tt p://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

If it were me, I'd first inspect the tires. If there's no "cupping" or uneven/funny looking wear, it's probably not them. You can go and have them balanced even if you choose, but if it's not all the time, it's likely not the tires. You could also try rotating them for the heck of it.

When was the last time you had any brake work done? (pads etc..) Sounds to me like it's time for a good brake job. If you haven't done the rotors or pads in the last 50k miles, I'd definately replace both and bleed the lines (replacing the fluid as well if it's pretty dark looking).

Edit: you can/should also check your brake lines as well.

Thanks for the post,
the tires don't have any un even wear pattern, and are actually due to be rotated, which i'll do sometime this week. I have had all of my pads done (rear was done three times due to locking calipers) so the pads are all good to go. Break lines themselves are intact, no seeping or leaking. And when we cleaned out the rear calipers we lost and added enough brake fluid sufficient for a replacement, so all aspects have been covered other than rotors themselves. I do believe the rears were grooved a bit after each caliper locked up. I hate the smell of burning pads away..
Old 09-27-2011, 06:42 AM
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Make sure you put on new pads with the new rotors. That way they will wear evenly together. New rotors and used pads might feel even worse at first, because the pads were wearing with the old rotors.

As far as when you should go with bigger rotors and pads, I'm not sure. But I'm planning on it when I finally make the switch to large tires.


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