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I have a neighbour's Pontiac Torrent that regardless how many high speed emergency stops I tried to do to scrub off the pad deposit, it didn't make a difference. One of the front rotors are causing a vibration when the brakes are applied at highway speeds. I'm starting to think the rotor (6months old) is actually warped.
Stage 1 is uneven pad deposits on the rotors from overheated rotors and/or wussy pads that can't take the heat. This causes brake judder, chatter, vibration, whatever you want to call it.
Stage 2 is uneven wear of the rotor caused by the aforementioned uneven pad deposits. This makes the judder/chatter/virbation permanent. Mic the rotor and you will see 1-2 thou difference in rotor thickness around the circumference.
Stage 3 is toss the rotors and start over. BTDT.
(One trick I read on the interwebs is to do some hard stops with Hawk blue racing pads, terribly abrasive to the rotors but will clean up uneven pad deposits and maybe even some uneven thickness. I haven't tried it, no affiliation, etc).
Better pads is a good start and worked for us. But sometimes you just gotta go bigger in order to dissipate the heat.
Yep, I'm aware of that and that has been the issue as the van is severely under braked. I'm just so pre-programmed to call it warping (my bad). But with the drilled and slotted rotors my brake temps are down now with one year on them. The longest I have gotten out of any rotor.
Now back to Porsche related content. I think they look cool, and for the amount I drive the car it works fine. But I do agree with others on the flat rotors lasting longer. Especially if you are driving daily, or in the winter.
Warping does happen, usually if the lugs are tightened unevenly and there is extreme heat!
My 928 4.5L has standard rear disc brakes and S version front disc setup. I am now at the point of buying the discs. I can buy EBC discs for a good price now. Full set front & rear with pads: EUR 745 or just the fronts: EUR 425. These are called "sport brakes"for whatever reason. I think they are cross drilled.
Alternatively I am offered EBC discs (I think standard, not cross drilled) without pads, front and rear for EUR 485 or EUR 319 just the fronts.
Are the cross drilled rotors worth the extra money? And should I buy the pads as well? I already have a new set of Pagid for the rears and Guttmann for the fronts on the shelf.
Now it appears that EBC discs are no longer available. Alternatively, I will get Textar discs (all 4). Any experience on these discs? Seem to bemostly sold for German cars like BMW and Mercedes
Autocrossed my 90GT and my braking style got the rotors VERY hot. Results were boiled brake fluid AND warped rotors with stock rotors and pads. Fronts only and that was with increased rear bias valve. Replaced the rotors with cryotempered slotted rotors and higher temp pads. Painted the rotors with that temperature reactive paint an it revealed the rotors were getting up to 800°F. With the higher temp pads and slotted cryotempered rotors the high temps solved the boiling and warping problems.
When I bought my 2001 Boxster S it came with drilled rotors. The Porsche materials said the holes were for better water egress, NOT better braking or cooling.
I've autocrossed my 94 GTS quite often and the only brake overheating problems I've had with it is melting the pad wear sensors. Just disconnected and jumpered them and no more problem.
Now it appears that EBC discs are no longer available. Alternatively, I will get Textar discs (all 4). Any experience on these discs? Seem to bemostly sold for German cars like BMW and Mercedes
The "S" fronts aren't available from many manufacturers. My suggestion is to go with Zimmerman and be content with the best, albeit most costly, rotors.
To search for rotors, I use an '84 928 as the target vehicle as all 928s, worldwide, had the "S" setup and there's no confusion about which rotors...unless the vendor has it wrong and I've gotten the wrong rotors at least twice for P-cars.
The "S" fronts aren't available from many manufacturers. My suggestion is to go with Zimmerman and be content with the best, albeit most costly, rotors.
To search for rotors, I use an '84 928 as the target vehicle as all 928s, worldwide, had the "S" setup and there's no confusion about which rotors...unless the vendor has it wrong and I've gotten the wrong rotors at least twice for P-cars.
the zimmermans are good stuff. raced on them for over 15 years. they are not too pricey either. however, if you want to go lower cost and improve the braking capabilities, you could go to the Cayanne rotors (13") but you need to some mods to make it work, like using a special adapter that i had made.. I have a couple left if you are interested.
otherwise, as glen says, be happy with the slottled, stock zimmermans. good stuff.
the zimmermans are good stuff. raced on them for over 15 years. they are not too pricey either. however, if you want to go lower cost and improve the braking capabilities, you could go to the Cayanne rotors (13") but you need to some mods to make it work, like using a special adapter that i had made.. I have a couple left if you are interested.
otherwise, as glen says, be happy with the slottled, stock zimmermans. good stuff.
EBC - nla
Textar - nla
Zimmerman is the only supplier left and that's what I get for the agreed upon price of EUR 485 fronts and rears
I just paid Roger $364 for all 4 Zimmemann Zinc coated rotors for my 80 S.
Plus $163 for Hawk HPS pads.
Hello Anders,
I just received the discs. They come with a leaflet that says not to remove the protective coating. The box also says the discs are coated. Just how good is this coating? I always like to see the centers and the airvents without rust, but nice grey paint. Does this coating stay or should I paint the centers and the airvents myself to keep that newish look?
10-27-2015, 01:21 AM
