Aaron68

Has anyone resurfaced/turned front rotors on our cars before? I replaced my front rotors not to long ago maybe around 20K miles or so but Im pretty sure they have warped somehow.

Im not exactly sure why they went bad so soon but I do suspect a couple of things.

1. I did notice that my bearing needed adjustment which may have contributed to warping. I just adjusted the front bearings but it made no difference as the damage is already done.

2. When I had my control arm bushings replaced I noticed that they used an impact gun to tighten my wheels.

Either way, whats done is done but I really do not want to pay $500 +$$$ for new rotors.

I always heard and have read on different treads that you're not supposed to resurface Mercedes rotors but the question is why? I have done it many times on other cars that I've owned with no problems. What makes this car so special?

The rotors are nice and thick with hardly any wear so Im thinking I should be OK. I am also running EBC Red pads.

Any ideas?

MarcusF

If someone can turn them and not go below 31mm, you'll be fine. The problem is, new W208 CLK55 rotors are only 32mm. At 30.4, they're ready for the trash. Too bad Willwood doesn't carry MB hats.

dlbehrns

No luck finding the specs for a 320 rotor. Do you have those Marcus or point me to where I can find them please? Or, where on the rotor is the minimum or max thickness stamped? TIA!
Also: Can anyone recommend a good micrometer? I see them online for anywhere from 5.99 for a digital readout to over $700 at Sears. thx!

MarcusF

Rotor specs for a W208? I think I've seen those.

The 430 and the 320 use the same rotors. The 55 uses $$$$another size$$$

dlbehrns

Interesting. I thought the 430 rotors were different/bigger than the 320. The price is the same at autohausaz.com. And the specs please and thank you? U dah Man!

MarcusF

For some reason, the first link failed. Here it is again, this time using Chrome rather than IE. Of course, it could have been that flaky chair-keyboard interface. I've been looking for a new one, but my wife is somewhat attached to the old.

Those are all the specs I can think of, rotor diameter, thickness when new, service limit thickness (when it's trash time), minimum thickness when installing new pads. Plus all the OE pad specs.

dannymk2

from what im told from most places that turn rotors is that new rotors are made alot cheaper then they used to be, with crappier metal, and cannot be turned as hot spots develop on the rotor. rotors now a days are usually cheap enough that they are just replaced rather then turned. i didnt believe this until i watched the guy try and turn a set of rotors for me and went through 4 bits and the rotor surface was screwed up. i replaced all the rotors on my clk with ones from autozone. they were fairly cheap and work great for me. ive used them on a bunch of different vehicles with zero issues.

AMG_BENZ

So, are you saying that the CLK55 rotors are better durability than the 430's? I wonder if the expensive CLK55 rotors would last longer than 430 rotors, which means it could be worth the cost.

By the way, why did you say too bad about Willwood? There are better brakes than Willwood, such as Brembos.

dlbehrns

55 rotors and their calipers are bigger than 430s. check Marcus's link above(thank U-M and the numbers are in millimeters) and you can see they are larger. I don't think you can trade the rotors straight across without changing the brake calipers as well but then Marcus duh Man would know.

Again, anybody recommend a good but not too expensive dial caliper? TIA.

MarcusF

Better is a relative term. I like Wilwood because the factory is about an hour from my house, and if they made the hats The replacement rotor costs would be fairly inexpensive. Although some like Brembo. It's relative to what someone wants. AMG rotors last about the same amount of time non-AMG CLK OE rotors; on the second brake job the rotors are typically beyond spec. Like DL said, CLK55 rotors are larger and cool better.

One of the reasons CLK55 rotors cost a fortune is they have directional cooling vanes. That means the left front only fits the left front. So, set up costs are double and the number of units sold would be half IF they fit every CLK out there, but they don't. They only fit AMGs, which were produced in smaller numbers. Very small numbers plus tooling that costs twice as much equals expensive. A picture is worth a thousand words, so you can read about radial and directional vanes here.

I got this one for about $25 at a home imptovement store. OSH? Home Depot? Lowes? One of 'em. Sears has them for about the same price.

AMG_BENZ

Yup, I already your article about cooling vanes. I have to admit, I really like the way AMG brakes perform. However, the scarcity and price are the big drawbacks. What do you mean the tooling is also expensive? It sounds like it requires expensive tools to replace the rotors, but I hope I am wrong.

MarcusF

By "tooling" I mean when the brakes are made, manufacturers use hardware to make them. Since radial vanes can be used on either side, the manufacturer can use a single mold to stamp out thousands of those with no hardware changes. Directional vanes can only be used on one side (half of the front rotors), so a different mold has to be used for the other half. Two molds versus one mold, twice the cost. The labor involved on a CLK55 brake job is the same as a CLK430/320. Same tools are required. The difference is in the price of the parts.