Well I know next time I'll feel for blisters around the back side of the hoses where I cant see

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

"Warped rotors" come from many sources, the most common being bad castings.

A casting that isn't properly stress-relieved, is machined in an un-natural state. When heated enough, some of that stress is relieved and the casting changes shape, causing a warped pulsation. This is the result of our auto-parts lowest bidder mentality, you don't need to know much about metallurgy to run a casting business in China.

Extreme heat can cause this also, but in racing back when rotors were all cast iron, a glowing red rotor didn't necessarily mean "warping", because they were manufactured properly and cooled mostly when running at high speeds which allowed them to cool slowly and evenly. Stopping when overheated is completely different, if you make a panic stop try to slowly roll forward for as long as possible.

Fast cooling as in water quenching will cause problems, can even crack a casting.

My rotors get rust on them some times, when I wash the car before putting it in the garage and don't drive it for a few days. Usually I try to drive it "around the block" (which is difficult when you live on an island) before garaging it to dry the brakes. If they sit and rust, I'll feel a pulsation sometimes for hundreds of miles.

My quattro had a re-occurring "warped rotor" issue when new in '85. Several sets of rotors/pads/shims, new tires, 2 new sets of BBS wheels later it was still occurring every couple thousand miles and audi would warranty it. Eventually I went to a different dealer and explained the issue/problem, we dial-indicated the wheels and everything, finally (at over 60,000miles) they replaced all four hubs along with the brakes, problem solved. Somehow a bad hub was causing the rotors to develop a lateral run-out issue which showed up as brake pulsation like a "warped rotor".

Our Ford vans typically need at least 3 sets of rotors every time brakes are done before a good set is found, I believe that Ford rotors are crap castings from some third-world country and they seem to stress-relieve/warp in the first thousand or so miles. I have gone to Autozone rotors on Fords because even those seem to be better quality than OE, and they have a good warranty. I have been told that Ford brakes are sensitive to improper lug-nut torque, but since I have always done these myself using the proper pattern and proper calibrated torque-wrench & torque, it's not why mine are problematic.

So there are at least a few reasons, pick your favorite.

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Gone to the dark side

- Jeff

My front left caliper has begun to drag, and I want to replace it. Called our favorite parts supplier to order one only to learn that the front calipers must match. Not wanting to replace both (and not knowing how to identify what I currently have....) I wonder if anyone can help?
1982 300SD.

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