Originally Posted By: LeakySeals
They are not warped, thats pretty much a myth. Rotors get slick spots from the pads. Some time over the summer you had to slam on the brakes and come to a stop from high speed. The pads sat and fried on the surface of the red hot rotor, creating a slick spot. After that its grip, slip, grip, slip, thats the vibration you're feeling. No need to machine or replace. Just remove, clean, put back. Buy better pads maybe. Machining the brakes simply removes the slick surface. It also thins the metal, making the surface hotter, less dissipation for heat. So this pad glazing problem becomes worse.
That is certainly a possibility.
But I have seen Discs that have been warped, which was confirmed by checking the runout. Again this was mainly before asbestos was removed from pad material. It was also only one or two vehicles.
I had a problem with pad material build up on my 04 Legacy, but also had an issue with one front calliper which caused one disc to warp, the top few mm of the disc was getting hotter than the rest of the disc, notnsure what the issue was with the Caliper as the car was bought brand new and had under 5000 miles on it at the time and was rarely driven hard.
The only reason they figured out what was going on was because the Mechanic at the 2bd Subaru Dealer I went into was ex Prodrive and actually knew what he wasn’t talking about rather than the parts fitters tab the previous Dealer.
They are not warped, thats pretty much a myth. Rotors get slick spots from the pads. Some time over the summer you had to slam on the brakes and come to a stop from high speed. The pads sat and fried on the surface of the red hot rotor, creating a slick spot. After that its grip, slip, grip, slip, thats the vibration you're feeling. No need to machine or replace. Just remove, clean, put back. Buy better pads maybe. Machining the brakes simply removes the slick surface. It also thins the metal, making the surface hotter, less dissipation for heat. So this pad glazing problem becomes worse.
That is certainly a possibility.
But I have seen Discs that have been warped, which was confirmed by checking the runout. Again this was mainly before asbestos was removed from pad material. It was also only one or two vehicles.
I had a problem with pad material build up on my 04 Legacy, but also had an issue with one front calliper which caused one disc to warp, the top few mm of the disc was getting hotter than the rest of the disc, notnsure what the issue was with the Caliper as the car was bought brand new and had under 5000 miles on it at the time and was rarely driven hard.
The only reason they figured out what was going on was because the Mechanic at the 2bd Subaru Dealer I went into was ex Prodrive and actually knew what he wasn’t talking about rather than the parts fitters tab the previous Dealer.
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