Novice brake question: It's about rotars.
 

Whenever I do my front brakes I'll take my front rotars to a mechanic who will examine and machine them if necessary (for $25.) He'll tell me when it's time for them to be replaced if need be.

Talking with a gal at work about this I realized I'm not totally sure what it means for the mechanic to 'turn' the rotar, what he's doing, and why exactly it's so important. :o

My questions:

* Why is it so important for the rotars to be turned when they need to be? I know it has something to do with the amount of wear on the surface. What happens if you don't have them machined?

* What exactly are they machining when they turn them? Are the smoothing them out or what?

To turn/machine a rotor is to grind down the surface so it is smooth and even around the entire surface, free of grouts and warps. This isn't necessarily required at any mile interval. If you have deep gouges in the surface, it's recommended that you have them turned to maintain surface area. If they're warped, it's really more a matter of comfort since surface area is not diminished.

If you search this forum for "rotors AND turn" you'll come up with many threads regarding this issue. Some people think you shouldn't turn them since they'll soon warp. I can't confirm or deny this since I've never had mine turned. Mine warped about 14,000 miles ago and I've been driving on them since. No reduced confidence in the braking ability, just a good level of discomfort with the resulting "hop" or "shimmy."

I'm soon going to replace my rotors entirely. I'll be buying PowerSlots (mainly for the look, not for the overrated performance increase). If it comes down to that decision for you, turning is a cheap option to at least buy yourself 15,000 miles before having to replace them. If you do replace, I know PowerSlot uses Brembo blanks (which you can get from TireRack.com), and I've also heard good things about NAPA's rotors.

This is probably way more information than you wanted or needed, but I'm thorough if nothing else. Good luck and happy trucking.

Thanks for the info Jeff.

>you have them turned to maintain surface area

Okay, that makes sense. If there are numerous pits in the surface that could weaken the gripping power of the brakes.

>they're warped, it's really more a matter of comfort since surface area is not diminished.

Yah, I like you drove around for quite awhile with my rotars warped. I finally changed the front pads/rotars because I couldn't stand that shutter when coming to a stop. It felt like a train rumbling down a track!

>I've also heard good things about NAPA's rotors

Yes, that's what I replaced my rotars with the last time. I have no problems with them but I will recommend not buying their pads. I used their pads and after awhile of driving they would begin to squeel and shriek very loud.

I finally replaced them with a pads purchased from the Ford dealership.

That's too bad. The NAPA pads had a lifetime warranty on them too.

In fact I have a set of front pads, barerly used (after doing a brake job I finally got fed up with the squeeling and bought the Ford) if you're interested. I'll sell them for 1/3 the cost. :)

I'm actually planning on using Hawk HPS pads (already purchased them). Not only because that's what PowerSlot recommends, but also because I've only heard good reviews on them. You might try them next time you change your pads.

I generally try not to buy any expendable items from Ford/Motorcraft, because I'm sure they charge a premium. If something equivalent (or better) is out there, I'd rather use it. The only exceptions to this rule is actual engine accessories (excluding performance upgrades). If I needed to replace the A/C or the water pump, etc., I'd rather use Ford parts for that. But for oil & filters, pads & rotors, etc. I'd just assume buy aftermarket.

-Jeff

>on using Hawk HPS pads (already purchased them).

I'll check those out. You're the 3rd person outside of this board to mention them.

>Ford/Motorcraft, because I'm sure they charge a premium

When I purchased my replacement pads from Ford the last brake-change interval I was surprised! I only paid $60 for them whereas the lifetime squeakers from NAPA were $75.00

>But for oil & filters

I agree fully on ya there. No since spending $1.25 more for the same filters.