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Hawk HP+ destroyed my rotors (need advice)

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  • Hawk HP+ destroyed my rotors (need advice)

    The car is a 2001 Honda Prelude only used for AutoX (10 or so a year) and Track Days (maybe 2 year).

    The rotors are Stoptech Slotteds (Cryogenically Frozen model) that were purchased from Tire Rack a few years ago.

    Since purchased, I've used the same rotors with Stock OEM pads, Brembo Street/AutoX pads, Stoptech Street/AutoX pads and now finally Hawk HP+s.

    I follow the brake bedding procedure each time but have never "turned the rotors" as I've read you cant do that with slotted rotors.

    Once I had the HP+s on, I did an autoX and noticed afterwards that my rotors now had grooves all around them. However there was no pulsing in the pedal and the brakes worked AMAZINGLY despite this (seemed simply cosmetic).

    Just did a Track Day at Mid-Ohio and while the rotors still look the same visually there is now all kinds of pulsing and grinding and other fun stuff when braking. Didn't notice it at all during the track day, just on the drive home.

    I took the pads and rotors off (pics attached). I clearly need new rotors (going to just get Brembo Blanks this time) but my question is, is there anything I can do to salvage the pads???
    They have just one autoX and one track day on them and plenty of life left in them. However as you can see in the pics, they look "chunky" or maybe "pitted" is a better word. I dont want to ruin a brand new set of brembo blanks but if i can at all avoid paying $115 for another set of pads at all. That'd be awesome.

    Please Advice :-)

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  • #2
    Are you also doing a lot of street driving with these pads on the car?

    Did you replace these pads just before your day at Mid-O?
    To the right of The Sheriff. Isn't everyone?


    • #3
      The pads were put on a month or so prior to the Mid-Ohio track day then used for one autoX, then the track day. The only street driving the car gets is to and from autoXs and track days.


      • #4
        It is hard to know for sure from the pictures, but it is possible you have excessive build up of pad material on the rotors. Rotors rarely warp, but it would be worth checking the run-out on them to make sure they are in fact all straight.

        I have heard that on occassion when changing from one compound type to another that excessive pad material can be deposited causing the symptoms you describe. The same can happen from driving with race grade pads, but not getting them hot enough while street driving. The HP+ is not that agressive so I would not expect that.

        After a day at Mid-O I would expect your rotors to look trashed, especially if you are driving to the limit.
        To the right of The Sheriff. Isn't everyone?


        • #5
          Is there a way to "smooth" out the HP+s and use them with the new rotors or should I just get new rotors and new pads?
          The HP+s were a Night and Day difference from the Brembo and Stoptech pads I had on previously, I went from needing a ton of braking to slow down to it feeling like I hit a wall every time I tapped the pedal.


          • #6
            You can resurface slotted rotors. I had the 2-piece stoptechs on my street car done to address a judder which would never go away. It worked perfectly.

            With those pads I'd just stick them in on the resurfaced rotors and go for it. They'll flatten themselves soon enough.

            What I don't understand is what caused that pitting and the high rotor wear rate in the first place. If resurfacing doesn't fix that underlying issue then the grooving and pitting will reoccur. But at least you're only out $30.


            • #7
              Thanks. I'm going to try to find a place to resurface the stop tech slotteds and see if that works. I'll post whether it works or not.


              • #8
                This sounds like uneven deposits. The rotor deposits can be invisible to the eye and may not even catch on a finger nail. This can generate pulsing under braking that's intolerable. This used to be more common with older street pad compositions, and even some pads marketed as street/track are a compromise (race pads rarely will do this). Years ago I had a set of brembo street pads get overheated and the shuddering under braking was as violent as a bad front tire flat spot. When the brakes are over worked and heated past their design parameters they'll do this (remember that the compromise with street pads is a lower operating temperature range and low wear rates inside that range -- outside that range = bad wear/performance). Driver, car, tires, weather, and brake components are all a variable. The HP+ are a good pad (I run them in my street car), but Hawk has much better pads exclusive for track duty (e.g. DTC).

                Your pads are likely fine. Those rotors look out of spec and it's time for new ones; >1.5mm?, growing surface fractures, and likely some cementite precipitating and contributing to the braking sensation you experienced. If you want to try salvage the rotors (or experiment), take them off and aggressively sand the rotor surfaces by hand. You can do by hand or with a electric hand sander. Grit isn't too important, 100-400 is sufficient. You won't hurt the rotors. It will be difficult to get any bite on the hardened rotor surface, but it will do a good job on the deposit. Another trick is to do a bed-in procedure with some aggressive metallic race pads (if you have them) that will clean up the rotors. These procedures don't always eliminate the problem, but they can be a substantial improvement. You can also lightly sand/file the pads on a block.

                I would not resurface the rotors beyond this. If you need to resurface it means you need new rotors. Also, I'm not sure cryo is worth it. More important to longevity and heavy usage is ductile iron (as opposed to low quality gray iron often with imports).

                Stop Tech used to have some excellent articles on this subject.


                • #9
                  Think I'm going to just get new Brembo blanks and put the pads as is on those. I'm not having any luck finding someone to turn the slotted rotors without
                  charging more than its worth to do as an experiment. The HP+s held up really well at mid-Ohio my biggest adjustment was trying to get used to having such
                  grippy brakes after using Street (HPS level) pads for so long. Hopefully the pads don't ruin my new Brembo blanks.


                  • #10
                    Resurface the rotors just past the imperfections. Sand down the pads just past the pitted part. Reinstall and bed-in per Hawk instructions. That should get you back to square one.


                    • #11
                      I hated my hawk pads, not much grip..... then they locked hard. switched over to Carbotechs and Never looked back, they eat rotors like crazy, their opinion(Carbotech) is that pads should eat rotors, but to basically skip buying any kind fancy rotors, and just replace them more often, there pads are like $200+ but well worth it! and there rotors seemed fairly cheap.

                      And I've turned slotted/cross drilled rotors.


                      • #12
                        I've found that the HPS and HP+ eat rotors at high temps and the Blues, 60s and 70s eat rotors at low temps. I run HPS on the street and switch to blues (I now use 60s for better grip) and now switch rotors as well, to match the pad. It makes a big difference in longevity.

                        But yes, any time you have high grip, something has to give. Metal or friction material. Oh and BTW turning slotted or drilled rotors is a common practice. Just watch the thickness.
                        Last edited by Gian; 09-14-2014, 05:21 PM.
                        That's not a Typo, I just can't spell no so well.


                        • #13
                          Originally posted by Gian View Post
                          I've found that the HPS and HP+ eat rotors at high temps and the Blues, 60s and 70s eat rotors at low temps. I run HPS on the street and switch to blues (I now use 60s for better grip) and now switch rotors as well, to match the pad. It makes a big difference in longevity.

                          But yes, any time you have high grip, something has to give. Metal or friction material.
                          I have been doing some testing with Hawk on a "DTC-80" The idea behind that pad is a lay down more pad material onto the rotor so there is more pad to pad friction in concept. It is to help save the rotor, but still have high grip an a long lasting high performance pad. I am not sure if it will be released or not.
                          To the right of The Sheriff. Isn't everyone?


                          • #14
                            So I put new brembo blanks on and just sanded the pads. Vibration went away at least during the bedding process. Won't know until next year if it all holds up during a track day. I saved the old rotors they seem to have plenty of "meat" left in them. Now I just have to find a place that will turn them in Columbus.


                            • #15
                              Any brake shop can machine the rotors. Some old-school parts stores, do it, too.