I guess I need rotors.

[Audi Junkie]

At 48k, the pads are down on my 07 Accord. I planned on reusing rotors because I generally have good luck with that. However, it seems I have a decent shimmy under moderate braking, much of the time....not always

The rotors look great, I'm not a whimp about doing and re-doing the brakes if needed, but is it worth trying to re-use the rotors for the $25 each (front only). If they don't work out I'll have to re-do with new ones.

Ideas?

 

[mechanicx]

I'd just replace the rotors too if you have a shimmy. Some people say rotors are rotors but I like to pay a few dollars more and get good ones like Raybestos advance technology. They've seemed to work good for me.

 

[Kestas]

First, measure the thickness of your existing rotors. Compare that with the specified discard thickness (sometimes stamped on the rotor). Some say you must use a micrometer, but a ruler is good enough for me.

In my experience, I find that rotors often start to shimmy once they're at minimum thickness.

 

[crazyoildude]

What brand are you replacing them with?

 

[beast3300]

If it is 4 wheel disc than you need to determine if it's the front rotors or the back. If it's rear drum then it's safe to say the rotors are warped before the drums (most of the time.)

At any rate, I would replace the rotors.

 

[oilboy123]

I sometimes replace and sometimes turn. I usually only turn when they are very meaty, and or they are not cheap for new ones.

If I feel after turning they are going to be less than half way to discard I won't turn them. If they are halfway there odds are I will be running on close to minimum thickness for awhile, and I don't want to do that if I can avoid it.

 

[willix]

Rotors are cheap. I bought a couple + grade at Napa for $35 each. They are definitely warped I can get them turned for half that price but will end up with true & straight but lop-sided rotors that probably will be a balance & thermal problem.

 

[ARCOgraphite]

I would only resurface for pad bedding, not to (try in vain to)correct a runout issue. My Toyota rotors are warped bad - I did a quick slow down on the interstate from 80 to 50 to hit an exit and the dealer hadent torqued the wheels evenly. I'm so glad I recently got my 30K service done at the toyota dealer - NOT!

 

[UNC017]

Originally Posted By: willix
Rotors are cheap. I bought a couple + grade at Napa for $35 each. They are definitely warped I can get them turned for half that price but will end up with true & straight but lop-sided rotors that probably will be a balance & thermal problem.


Shouldn't happen. Most rotors aren't truly warped to a large extent, but have developed an uneven surface texture that makes the pads grip one area better than the rest which induces the shimmy feel. Resurfacing fixes that, trues up any actual warp that there might be, AND you're left with "seasoned" (stress-relieved due to many heat cycles) rotors instead of virgin rotors that have to start the heat cycling (and possible surface anomaly formation) all over again. I'm a big fan of turning rotors rather than replacing them, so long as there's enough meat left.

 

[Audi Junkie]

They barely have any wear. I did get some pulsing, grabbing more and less as the wheels rotated. The braking situation is much different where I live now, nothing but red lights as far as you can see verses inter-town crusing. The system is undersized for the weight of the car as well.

The difference being that If I don't want to save the rotors, I can run the existing pads down farther. I priced Advance rotors at $20 w/coupon.

Wearever

 

[tig1]

If you replace don't use the cheap China stuff.

 

[oilboy123]

Originally Posted By: tig1
If you replace don't use the cheap China stuff.

As opposed to the Expensive China stuff...?

I wish it was as easy as it once was.....

Really hard to do.

 

[Herz]

Originally Posted By: oilboy123
Originally Posted By: tig1
If you replace don't use the cheap China stuff.

As opposed to the Expensive China stuff...?

I wish it was as easy as it once was.....

Really hard to do.


NAPAs premium line is US made.

 

[ET16]

Brembo rotors are good, too. The ones I've gotten haven't been made in China.

 

[UNC017]

Originally Posted By: Audi Junkie

The difference being that If I don't want to save the rotors, I can run the existing pads down farther. I priced Advance rotors at $20 w/coupon.

Wearever


If I understand you right, you're considering NEW rotors and continuing to use the old pads??? I wouldn't. IMO that's a really good way to get a screwy surface finish started on the new rotors, resulting in them having the same "grabby" feel before the end of your old pads' life, and not working well with new pads thereafter.

If it were my car, I'd resurface the old rotors and get new pads now. In fact I did that just two weeks ago when I picked up the 01 Cherokee from a cow-orker. It had horrible pulsation/shimmy under moderate braking with no apparent/visible wear oddities on the pads or rotors. Re-surfaced the rotors, put on new ceramic pads, and now it stops silk smooth, just like the '99 has done for the 3 years since I gave it exactly the same treatment.

 

[Audi Junkie]

No, I'm due for a brake job. I have some Wagner TQs, just wondering about re-using rotors.

 

[SteveSRT8]

Originally Posted By: 440Magnum
Originally Posted By: willix
Rotors are cheap. I bought a couple + grade at Napa for $35 each. They are definitely warped I can get them turned for half that price but will end up with true & straight but lop-sided rotors that probably will be a balance & thermal problem.


Shouldn't happen. Most rotors aren't truly warped to a large extent, but have developed an uneven surface texture that makes the pads grip one area better than the rest which induces the shimmy feel. Resurfacing fixes that, trues up any actual warp that there might be, AND you're left with "seasoned" (stress-relieved due to many heat cycles) rotors instead of virgin rotors that have to start the heat cycling (and possible surface anomaly formation) all over again. I'm a big fan of turning rotors rather than replacing them, so long as there's enough meat left.


Oh No! This can't be true?

I posted this info and was bally hooed to death over it.

But it remains a fact. Many times the cure is as simple as learning not to sit with your foot on the brake after a hard stop.

But mostly this reflects a pad issue that harmed the rotors. Get the right pad (I use NAPA Adaptive 1) and all your brake problems go away!

At 25 bucks I'd buy new ones. Many times the whole lathing operation introduces runout issues due to poorly trained techs or bad equipment.

 

[mechtech2]

$25 each for cutting?
Get new ones, for sure.
Shimmy may be out of true, or uneven pad material deposits that caused metalurgical changes in the face of the rotor. Internal rust on the vents can cause pressure that makes a rotor bulge and warp.

 

[Audi Junkie]

I take care not to sit with the brakes applied after a hard long stop. I actually let the car creep forward a bit.

 

[Mr_Incredible]

Before buying new rotors, if the old ones look good, clean behind the wheel with a wire brush to take off any dirt/corrosion that may have built up. Likewise with the rotor where the wheel meets it. It could easily be buildup causing the rotors to pulse. The price is right and it could fix the issue.