[mikenigro]

I'm getting ready to replace the front brakes on my 2007 Santa Fe that just turned over 40,000 miles. My question: does anyone have a recommendation or can you provide comments on your own experience with replacing pads and/or rotors? Specifically, what kind, manufacturer, etc. do you recommend? The Hyundai dealership quoted me $87.00 for front brake pads and $165 each for front rotors if I need them. Any thoughts or input would be appreciated.

 

[Don67]

It is unlikely that you need new front rotors on an '07, especially one driven where there is no road salt. Usually they can be machined and used for another 2-3 years after the first brake job.

The best way to keep the dealership honest is to ask for their recommendations in writing, and let them know that you would like any worn-out parts returned to you at the end of the job.

 

[looney]

i went with rockauto.com when i did my rears, i got raybestos pads and rotors for half of what the dealer wanted.

 

[canderson]

If you want to keep your dealer honest ... per Hyundai spec you're allowed 1.6mm of wear.

Hyundai builds the 07 with 28mm front rotors (vented) and specifies replacement at below 26.4mm with a max 0.03mm runout.
They use 11mm rear rotors (solid) with replacement spec'd at less than 9.4mm with a max 0.03mm runout.

 

[Nittany Lioness]

Remind me again what "runout" is, and where you measure it?

 

[canderson]

QUOTE (Nittany Lioness @ Jun 28 2010, 07:47 AM) index.php?act=findpost&pid=336732

Remind me again what "runout" is, and where you measure it?

Picture a bent bicycle tire rim. While the thickness of the rim (rotor) might be identical at all points, if you spin it, the extreme of the travel as you look at the width of the tire while it's spinning is taking up a bunch more space. The amount of side-side travel is ideally zero. The run-out is the amount that the tire is wandering left and right as it spins.

In practical terms, you mount the rotor on a bench fixture that spins it in place and you take a device that measures distance and run it up against the rotor and watch it while you rotate the rotor. Whatever right/left displacement the rotor causes to the measuring device is indicated on a dial (or digital) indicator.

Too much run-out means that as the rotor rotates, it's going to be banging back and forth against the brake pads when you apply the brakes. That will come across as a "thumping" with each rotation. It reduces braking power and increases wear.

 

[Nittany Lioness]

Thanks for the excellent explanation.
Since we installed two entirely new rotors and pads in the rear,
our occasional "whoosh-whoosh-whoosh" sound coming from those wheels wouldn't be a run-out issue, I gather.

But if the "bench fixture" is possibly bent or not parallel with the resting part of the rotor,
I wonder if that could be enough to have the rotor and pads still making contact.

We *ahem* did whack on that one rear rotor behind it by jamming a big screwdriver between the rotor and the housing,
and slammed on it for a day and a half (thinking rust had cemented it) until we realized the emergency brake release wasn't ... released.
Then it came right off. Yes, we were idiots.
Things looked fine, except for the thin ... what do you call it vertical round thin pan that the rotor is housed in,
that was a bit bent in spots. Now that I think of it, there was a fresh wear spot on the inside of that when we initially pulled the rotor off. So even before the whacking we did, it was rubbing in there.

So the original problem caused that, and new rotors didn't solve it.

Could the entire rear axle maybe be slightly bent or misaligned?
Wonder if alignments are covered under warranty.

I do ride it on my mile long rough mountain road daily.