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Rotor Whoa's... Need some advice


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Ok, In late Feb I purchased a Front & Rear set of Zimmerman Cross-Drilled & Slotted rotors from ebay. About 3 weeks ago I noticed a tad bit of wobble under braking and 1 week ago it had gotten alot worse and more obvious that the rotors were the cause of the wobble.

Now they wobble like a mofo when braking at speeds higher than 60mph. Emailed the Seller and told him if they can replace them, since i see a similar auction on ebay for the same rotors but with a 6 month warranty.

They replied with "rotors come with 30 day warranty". So that avenue is no good for me. Rather than Replace the rotors all over again, Is there anyway I can have them cut/straightened?

I heard that not all Rotor cutting machines can do Cross-Drilled/Slotted rotors but some can... Is this true? if so, where might I find a shop with this type of machine in the Los Angeles area?

Any advise or ideas welcome.

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You might try calling a shop that specializes in brakes to see if they can cut the rotors. If they can, have them cut, then make sure you reinstall the wheels with the proper torque on the lugs so they don't warp again. Also, after periods of hard braking make sure you drive around a bit to cool the brakes. Lastly, after an autocross run or hard braking session, don't apply the emergency brake when you park the car. Just leave it in gear.

Be forewarned: brake rotors that have warped are likely to warp again due to decreased overall mass.

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Generally speaking there will be enough meat on Zimmrman rotors to do a skim cut, at the least, and that might true them up. I've seen cross drilled rotors cut before and don't believe it requires much more than a skilled lathe operator with a sharp tool.

The basic problem, however, is that you are dealing with one-piece rotors that do not disapate the heat well without warping. The solution is a two-piece rotor that has some level of float between the outer rotor and center section. Two-piece rotors are a lot more expensive, but they rarely warp. I installed Boxster claipers on the front of my VW GTi a couple of yeasrs ago and eventually had to go to 13" two-piece AWE rotors to stop the warping because the Zimmerman rotors turned to potato chips in very few miles.

Lyn

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Make sure they are truly warped. In my travels this is an over used term for standard road cars. The rotors may cause uneven pad wear or the calipers may not be preforming well but it sure takes a lot of heat or poor quality to warp a rotor from standard road use. Racers need not argue!

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Make sure they are truly warped. In my travels this is an over used term for standard road cars. The rotors may cause uneven pad wear or the calipers may not be preforming well but it sure takes a lot of heat or poor quality to warp a rotor from standard road use. Racers need not argue!

I heard something....I'm not sure if it true, so maybe someone can verify.

US shops are buying (in quantity) Zimmerman's that have no drilling. They are just cast rotors. Then the local US shop drills them and slots them and finally some dip them. In tune they sell them on ebay for big bucks.

I found a few articles about the process of dipping them especially when it comes ti Cadmium, Zinc-Nickle and other coatings.

Anyway, maybe someone has some info to back this up.

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Zimmerman's are very prone to rusting on the inside face. This will cause judder at high speed and yet remain unnoticed at lower traffic-type speeds.

This emphasis the old routine of padding brakes after washing etc - do some hard braking if you haven't used the car for a while etc.

You should be able to skim them back into life at an independent porsche specialist.

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